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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.
471

Stochastic Modeling of Electricity Prices and the Impact on Balancing Power Investments / Stokastisk modellering av elpriser och effekten på investeringar i balanskraft

Ruthberg, Richard, Wogenius, Sebastian January 2016 (has links)
Introducing more intermittent renewable energy sources in the energy system makes the role of balancing power more important. Furthermore, an increased infeed from intermittent renewable energy sources also has the effect of creating lower and more volatile electricity prices. Hence, investing in balancing power is prone to high risks with respect to expected profits, which is why a good representation of electricity prices is vital in order to motivate future investments. We propose a stochastic multi-factor model to be used for simulating the long-run dynamics of electricity prices as input to investment valuation of power generation assets. In particular, the proposed model is used to assess the impact of electricity price dynamics on investment decisions with respect to balancing power generation, where a combined heat and power plant is studied in detail. Since the main goal of the framework is to create a long-term representation of electricity prices so that the distributional characteristics of electricity prices are maintained, commonly cited as seasonality, mean reversion and spikes, the model is evaluated in terms of yearly duration which describes the distribution of electricity prices over time. The core aspects of the framework are derived from the mean-reverting Pilipovic model of commodity prices, but where we extend the assumptions in a multi-factor framework by adding a functional link to the supply- and demand for power as well as outdoor temperature. On average, using the proposed model as a way to represent future prices yields a maximum 9 percent overand underprediction of duration respectively, a result far better than those obtained by simpler models such as a seasonal profile or mean estimates which do not incorporate the full characteristics of electricity prices. Using the different aspects of the model, we show that variations of electricity prices have a large impact on the investment decision with respect to balancing power. The realized value of the flexibility to produce electricity in a combined heat and power plant is calculated, which yields a valuation close to historical realized values. Compared with simpler models, this is a significant improvement. Finally, we show that by including characteristics such as non-constant volatility and spiky behavior in investment decisions, the expected value of balancing power generators, such as combined heat and power plants, increases. / I takt med att fler intermittenta förnyelsebara energikällor tillför el i dagens energisystem, blir också balanskraftens roll i dessa system allt viktigare. Vidare så har en ökning av andelen intermittenta förnyelsebara energikällor även effekten att de bidrar till lägre men också mer volatila elpriser. Därmed är även investeringar i balanskraft kopplade till stora risker med avseende på förväntade vinster, vilket gör att en god representation av elpriser är central vid investeringsbeslut. Vi föreslår en stokastisk flerfaktormodell för att simulera den långsiktiga dynamiken i elpriser som bas för värdering av generatortillgångar. Mer specifikt används modellen till att utvärdera effekten av elprisers dynamik på investeringsbeslut med avseende på balanskraft, där ett kraftvärmeverk studeras i detalj. Eftersom huvudmålet med ramverket är att skapa en långsiktig representation av elpriser så att deras fördelningsmässiga karakteristika bevaras, vilket i litteraturen citeras som regression mot medelvärde, säsongsvariationer, hög volatilitet och spikar, så utvärderas modellen i termer av årlig prisvaraktighet som beskriver fördelningen av elpriser över tid. Kärnan i ramverket utgår från Pilipovic-modellen av råvarupriser, men där vi utvecklar antaganden i ett flerfaktorramverk genom att lägga till en länkfunktion till tillgång- och efterfrågan på el samt utomhustemperatur. Vid användande av modellen som ett sätt att representera framtida priser, fås en maximal över- och underprediktion av prisvaraktighet om 9 procent, ett resultat som är bättre än det som ges av enklare modellering såsom säsongsprofiler eller enkla medelvärdesestimat som inte tar hänsyn till elprisernas fulla karakteristika. Till sist visar vi med modellens olika komponenter att variationer i elpriser, och därmed antaganden som används i långsiktig modellering, har stor betydelse med avseende på investeringsbeslut i balanskraft. Det realiserade värdet av flexibiliteten att producera el för ett kraftvärmeverk beräknas, vilket ger en värdering nära faktiska realiserade värden baserade på historiska priser och som enklare modeller inte kan konkurrera med. Slutligen visar detta också att inkluderandet av icke-konstant volatilitet och spikkarakteristika i investeringsbeslut ger ett högre förväntat värde av tillgångar som kan producera balanskraft, såsom kraftvärmeverk.
472

Physics and applications of conductive filaments in electronic structures: from metal whiskers to solid state memory

Niraula, Dipesh 05 September 2019 (has links)
No description available.
473

ON THE RATE-COST TRADEOFF OF GAUSSIAN LINEAR CONTROL SYSTEMS WITH RANDOM COMMUNICATION DELAY

Jia Zhang (13176651) 01 August 2022 (has links)
<p>    </p> <p>This thesis studies networked Gaussian linear control systems with random delays. Networked control systems is a popular topic these years because of their versatile applications in daily life, such as smart grid and unmanned vehicles. With the development of these systems, researchers have explored this area in two directions. The first one is to derive the inherent rate-cost relationship in the systems, that is the minimal transmission rate needed to achieve an arbitrarily given stability requirement. The other one is to design achievability schemes, which aim at using as less as transmission rate to achieve an arbitrarily given stability requirement. In this thesis, we explore both directions. We assume the sensor-to-controller channels experience independently and identically distributed random delays of bounded support. Our work separates into two parts. In the first part, we consider networked systems with only one sensor. We focus on deriving a lower bound, R_{LB}(D), of the rate-cost tradeoff with the cost function to be E{| <strong>x^</strong>T<strong>x </strong>|} ≤ D, where <strong>x </strong>refers to the state to be controlled. We also propose an achievability scheme as an upper bound, R_{UB}(D), of the optimal rate-cost tradeoff. The scheme uses lattice quantization, entropy encoder, and certainty-equivalence controller. It achieves a good performance that roughly requires 2 bits per time slot more than R_{LB}(D) to achieve the same stability level. We also generalize the cost function to be of both the state and the control actions. For the joint state-and-control cost, we propose the minimal cost a system can achieve. The second part focuses on to the covariance-based fusion scheme design for systems with multiple > 1 sensors. We notice that in the multi-sensor scenario, the outdated arrivals at the controller, which many existing fusion schemes often discard, carry additional information. Therefore, we design an implementable fusion scheme (CQE) which is the MMSE estimator using both the freshest and outdated information at the controller. Our experiment demonstrates that CQE out-performances the MMSE estimator using the freshest information (LQE) exclusively by achieving a 15% smaller average L2 norm using the same transmission rate. As a benchmark, we also derive the minimal achievable L2 norm, Dmin, for the multi-sensor systems. The simulation shows that CQE approaches Dmin significantly better than LQE. </p>
474

Exploring the feasibility of seawater flush toilets for rural, coastal areas

Conroy, Kristen M. 08 September 2022 (has links)
No description available.
475

Factors that influence pregnant women’s utilisation of anti-malaria services in the Buikwe district of Uganda

Bbosa, Richard Serunkuma 11 1900 (has links)
Text in English / Malaria is endemic throughout Uganda and the leading cause of morbidity and mortality. Malaria causes complications in 80.0% of all pregnancies in Uganda. This study attempted to identify factors that influence pregnant women’s utilisation of anti-malaria services in the Buikwe district of Uganda. These factors were contextualised within the Social Learning Theory’s major concepts. The target populations comprised pregnant women attending antenatal clinics (phase 1) and midwives providing antenatal services (phase 2) at 16 clinics in the Buikwe district of Uganda during the data collection phase of the study. Structured interviews were conducted with a sample of 400 randomly selected pregnant women and with the accessible population of 40 midwives. Pregnant women, who had progressed beyond primary school level education, were more likely to take intermittent preventive treatment (IPT) drugs and to use long lasting insecticide treated nets (LLINs) to prevent malaria. Pregnant women were more likely to implement malaria-preventive actions if they lived within five kilometres of clinics, were satisfied with available health services, were knowledgeable about the malaria preventive measures and had used IPT during previous pregnancies. Pregnant women who implemented one malaria-preventive action were likely to implement other actions as well (Pearson’s correlation coefficient was 0.65; p<0.05). Midwives’ provision of malaria-preventive services to pregnant women were influenced by the availability of IPT drugs, accessibility of safe drinking water, frequency of giving health education to pregnant women, cooperation with village health teams, malaria-related in-service training, midwives’ education level and experience. Although 97.9% of the pregnant women had taken IPT and 84.2% of those who had received LLINs, utilised these nets, malaria prevention during pregnancy could be improved. All pregnant women should attend antenatal clinics at least four times during each pregnancy, commencing during the first trimester of pregnancy to receive adequate health education and prenatal services, including IPT and LLINs. All midwives should receive malaria-related in-service training. Regular audits of midwives’ records should identify and address strengths and weaknesses related to the prevention and management of malaria during pregnancy. Such actions could enhance the prevention and management of malaria, estimated to affect 80% of pregnant women in Uganda. / Health Studies / D. Litt. et Phil. (Health Studies)
476

Knowledge and use of intermittent prevention for malaria among pregnant women attending antenatal clinics in health centers in the Federal Capital Territory, Nigeria

Emenike, Obiageli Ugwumsinachi 02 1900 (has links)
Background Plasmodium falciparum malaria during pregnancy poses a substantial risk to mother and foetus. In recent years, convincing evidence has shown that preventive methods such as the use of insecticide treated bed nets (ITNs) and intermittent preventive treatment (IPT) in pregnancy with sulphadoxine-pyrimethamine (IPTp-sp) can greatly reduce the adverse effects of malaria during pregnancy. Purpose The main purpose of the study was to assess the knowledge and use of Intermittent Preventive Treatment of Malaria among pregnant women receiving Antenatal Care at the primary health centers of the Federal Capital Territory, Abuja Nigeria. Methods A quantitative, descriptive, cross-sectional study was conducted Structured questionnaires were administered to 300 pregnant women aged between 18 and 49 years. Data was analysed using Statistical Package for Social Sciences (SPSS) 22. Results The results revealed that most of the respondents had knowledge about IPT, majority of the respondents had received IPT drugs, in the clinic, but unfortunately none of them were supervised by a health worker during taking of the drug. Few of the respondents did not take the drugs at all for fear of complication, some of them did not know exactly how many tablets were given to them and there was poor adherence to the Directly Observed Therapy (DOT) scheme. Conclusion Knowledge of malaria and IPT was good and many pregnant women received the drugs and used it, but some of them had challenges and did not use the drugs. / Health Studies / M.P.H.
477

Auswirkungen religiösen Fastens auf anthropometrische Parameter, Blutfettwerte und Hämodynamik normalgewichtiger gesunder Probanden

Liebscher, Daniela 04 September 2012 (has links)
Ärzte sind in einer multikulturellen Gesellschaft gefordert, gesundheitsrelevante kulturelle Besonderheiten wie das religiös motivierte Fasten zu berücksichtigen, welches in unterschiedlicher Ausprägung in vielen Religionen eine zentrale Rolle einnimmt. Im Judentum gibt es vierundzwanzigstündige Fastenzeiten mit strikter Nahrungs- und Flüssigkeitskarenz. Im Christentum gibt es Fasten, welche eine veränderte Zusammensetzung der Nahrung während der Fastentage vorsehen, wie das Fasten der griechisch-orthodoxen Kirche oder das Daniel Fasten, während bei römisch-katholischen oder protestantischen Fastenexerzitien oft Heilfasten mit Nahrungskarenz praktiziert werden. Im muslimischen Mondmonat Ramadan wird tagsüber sowohl auf Nahrung als auch auf Trinken verzichtet. Das Hauptziel dieser Arbeit war, die bisher erforschten Auswirkungen der verschiedenen Fastenarten auf anthropometrische Parameter, Blutfettwerte und Hämodynamik bei normalgewichtigen, gesunden Fastenden zu untersuchen. Die Literaturrecherche wurde vorwiegend in pubmed und für das Heilfasten zusätzlich in zwei Spezialbibliotheken durchgeführt. Bei der Auswertung erfolgte zur Verbesserung der Vergleichbarkeit der Ergebnisse eine Einteilung der Studien in Gruppen nach definierten Qualitätskriterien. Zur Beurteilung der Ergebnisse wurde einzeln auf die untersuchten Themenkomplexe eingegangen. Anthropometrische Parameter: Während beim Jom Kippur nur eine leichte Abnahme des Körpergewichts aufgrund von Verschiebungen im Flüssigkeitshaushalt vorkamen, konnten bei einwöchigem Heilfasten und beim Daniel Fasten keine signifikanten Ergebnisse dokumentiert werden. Beim griechisch-orthodoxen und Ramadan-Fasten zeigte sich eine Abnahmetendenz für Gewicht und Body-mass-Index (BMI), welche sich mit der Länge des Fastens zu verstärken scheint. Für keine der Fastenarten konnte bisher ein Rebound- Effekt nachgewiesen werden. Blutfette: Im Fettstoffwechsel beobachtete Veränderungen während des Jom Kippur sind aufgrund der Kürze des Fastens lediglich als passager zu bewerten. Die zum griechisch-orthodoxen und Daniel Fasten vorliegenden Studien konnten bisher die Reduktion des Gesamt- und LDL-Cholesterols belegen, während beim Heilfasten die kurzfristigen Effekte widersprüchlich erscheinen und wenig Langzeitergebnisse vorhanden sind. Beim Ramadan-Fasten war die Variabilität der Ergebnisse groß, wobei sich jedoch fast durchgehend eine Erhöhung der Werte für HDL und HDL-Cholesterol zeigte. Hämodynamik: Zusammenfassend kann man bei der dürftigen Studienlage für alle Fastenarten entweder keine Veränderung oder eine Tendenz zur Verbesserung der Blutdruckwerte sehen. Der Vergleich des menschlichen Fastens mit Grundlagenstudien zur Kalorienrestriktion oder zum intermittierenden Fasten bei Tieren, welche deutlich gesundheitsfördernde Ergebnisse zeigen, scheint nicht uneingeschränkt zulässig. Aufgrund der Studienlage kann derzeit nicht beantwortet werden, ob diese positiven Effekte auch durch regelmäßiges religiöses Fasten im menschlichen Körper erzielt werden können. Die meisten Studien zum religiösen Fasten sind Beobachtungsstudien, deren verschiedene Umgebungsbedingungen den Vergleich der Ergebnisse, insbesondere beim Ramadan-Fasten, erschweren. Bis auf wenige Ausnahmen kommen die Studien aus Ländern, in denen das jeweilige Fasten traditionell praktiziert wird. Die Arbeit zeigt den Facettenreichtum der vorhandenen religiösen Fastenpraktiken und ihre Relevanz für die heutige medizinische Praxis. Lücken in der Studienlage und qualitative Mängel der bestehenden Daten konnten aufgezeigt werden. Es bleibt zu hoffen, dass die Anzahl der qualitativ hochwertigen Studien zu allen verbreiteten Arten des Fastens weiterhin wächst und dass derzeit noch nicht medizinisch untersuchte Fasten zukünftig ebenso in die Forschung einbezogen werden.:1.EINFÜHRUNG 4 1.1 Vorwort und Fragestellung 4 1.2 Hintergründe- Einführung in ausgewählte religiöse Fastenarten 4 1.2.1 Definition des Begriffes „religiöses Fasten“ 4 1.2.2 Fasten im Judentum 6 1.2.4 Fasten im Christentum 7 1.2.4.1 Fasten der östlich-orthodoxen Kirchen 7 1.2.4.2 Daniel-Fasten 8 1.2.4.3 Heilfasten 9 1.2.5 Fasten im Islam 11 2. METHODIK UND VORGEHENSWEISE 14 2.1 Literaturrecherche in PubMed 14 2.2 Literaturrecherche in ausgewählten Bibliotheken 19 2.3 Qualitätskriterien für Studien 20 3. ERGEBNISSE 23 3.1 Jom Kippur 24 3.2 Christliches Fasten 26 3.2.1 Fasten der östlich-orthodoxen Kirchen 26 3.2.2 Daniel-Fasten 29 3.2.3 Heilfasten 32 3.3 Ramadan-Fasten 38 3.4 Zusammenfassung der Ergebnisse 68 4. DISKUSSION 70 4.1 Beurteilung bestimmter Aspekte der gesundheitlichen Wirkung des religiösen Fastens 70 4.1.1 Körpergewicht und BMI 70 4.1.2 Blutfettwerte 74 4.1.3 Hämodynamik 80 4.1.4 Vergleich der gesundheitlichen Wirkung mit den Resultaten von Grundlagenstudien 84 4.2 Methoden- und Quellenkritik 88 4.2.1 Vergleichbarkeit Heilfasten- religiöses Fasten 88 4.2.2 Konsequenzen aus der vorhandenen Forschung für andere Fastenarten 91 4.2.3 Qualität und Quantität der untersuchten Studien 95 4.2.4 Methodenkritik und Diskussion der Ausschlusskriterien 97 4.2.5 Vorschläge für weitere Studien 100 5. ZUSAMMENFASSUNG UND AUSBLICK 102 6. ANHÄNGE 106 6.1 Abkürzungen 106 6.2 Weitere verbreitete religiöse Fastenarten 106 7. QUELLENANGABEN 109 / In a multicultural society doctors are required to consider health-related cultural features such as religious fasting, which, to varying degrees, play a central role in many religions. In Judaism fasting is a strict twenty-four hour abstention from food and fluids. In Christianity there are fasts that involve a change in the variety of foods eaten, as is the case in the Greek Orthodox Church or in the Daniel Fast, while in Roman-Catholic or Protestant fasting retreats a juice fast is often observed. In the Islamic lunar month of Ramadan food and fluid intake is restricted to the night hours only. The main purpose of this study was to investigate the findings of existing research into the impact of different kinds of religious fasting on anthropometric parameters, blood lipids and haemodynamics of healthy people. The literature research has been carried out mainly through pubmed and for the juice fast two additional, specialised libraries were consulted. For the evaluation and a better comparability of the results the studies were classified into groups, defined by specific qualitative criteria. For the purpose of evaluating the results, they were analysed in groups according to the main criteria of the study. Anthropometric parameters: while during Jom Kippur only a slight reduction of body weight due to shifts in the body\\\'s fluid balance could be observed, in a one-week juice fast and in a Daniel Fast there were no significant changes. In the Greek Orthodox and Ramadan fasts a tendency to reduction of body weight and body mass index (BMI) were observed, which seemed to intensify according to the length of the fast. In none of these fasts a rebound effect was found. Blood lipids: the changes observed in lipid metabolism during Jom Kippur should be regarded as transient due to the shortness of the fast. The studies of Greek Orthodox and Daniel fasting have shown a reduction of total and LDL cholesterol, while those examining juice fasting reveal the short term effects as contradictory, with there being only few long term results available. The results pertaining to Ramadan fasting showed a high variability, though a rise in HDL and HDL cholesterol has been quite consistently reported. Haemodynamics: in summary it can be stated, considering the very sparse number of studies in this area, that in all of the above mentioned forms of religious fasting there was either no change or a slight tendency towards a reduction of blood pressure. The comparison of human fasting to experimental studies in caloric restriction or intermittent fasting in animals, which have clearly shown health enhancing effects, does not seem unconditionally valid. Based on the current state of science no definitive answer can be given on whether regular religious fasting can generate these positive results in humans. Most studies in the field of religious fasting are observational studies with differing environmental conditions, a fact that hampers the comparison of the results, especially for the Ramadan fast. Except for few exemptions the studies all originate in countries where the respective fast is traditionally held. This study revealed the great variety within the existing religious fasting practices and their relevance for today’s medical practice. Gaps in the current state of evidence and research as well as qualitative shortcomings in the existing data where revealed. It is to be hoped that the rise in high-quality studies of all common religious fasts will continue and that fasts, not medically studied to date, will in future also become the subject of research.:1.EINFÜHRUNG 4 1.1 Vorwort und Fragestellung 4 1.2 Hintergründe- Einführung in ausgewählte religiöse Fastenarten 4 1.2.1 Definition des Begriffes „religiöses Fasten“ 4 1.2.2 Fasten im Judentum 6 1.2.4 Fasten im Christentum 7 1.2.4.1 Fasten der östlich-orthodoxen Kirchen 7 1.2.4.2 Daniel-Fasten 8 1.2.4.3 Heilfasten 9 1.2.5 Fasten im Islam 11 2. METHODIK UND VORGEHENSWEISE 14 2.1 Literaturrecherche in PubMed 14 2.2 Literaturrecherche in ausgewählten Bibliotheken 19 2.3 Qualitätskriterien für Studien 20 3. ERGEBNISSE 23 3.1 Jom Kippur 24 3.2 Christliches Fasten 26 3.2.1 Fasten der östlich-orthodoxen Kirchen 26 3.2.2 Daniel-Fasten 29 3.2.3 Heilfasten 32 3.3 Ramadan-Fasten 38 3.4 Zusammenfassung der Ergebnisse 68 4. DISKUSSION 70 4.1 Beurteilung bestimmter Aspekte der gesundheitlichen Wirkung des religiösen Fastens 70 4.1.1 Körpergewicht und BMI 70 4.1.2 Blutfettwerte 74 4.1.3 Hämodynamik 80 4.1.4 Vergleich der gesundheitlichen Wirkung mit den Resultaten von Grundlagenstudien 84 4.2 Methoden- und Quellenkritik 88 4.2.1 Vergleichbarkeit Heilfasten- religiöses Fasten 88 4.2.2 Konsequenzen aus der vorhandenen Forschung für andere Fastenarten 91 4.2.3 Qualität und Quantität der untersuchten Studien 95 4.2.4 Methodenkritik und Diskussion der Ausschlusskriterien 97 4.2.5 Vorschläge für weitere Studien 100 5. ZUSAMMENFASSUNG UND AUSBLICK 102 6. ANHÄNGE 106 6.1 Abkürzungen 106 6.2 Weitere verbreitete religiöse Fastenarten 106 7. QUELLENANGABEN 109
478

探討N-甲基-D-天門冬胺酸受體在時距相關的操作式制約行為與空間工作記憶的角色:memantine的神經心理藥理學機制 / Investigation of the role of N-methyl-D-aspartate (NMDA) receptors on temporal operant behavior and spatial working memory: the underlying neuropsychopharmacological mechanisms of memantine

陳碩甫 Unknown Date (has links)
認知功能的提升是當今神經科學領域中的研究重點之一,但其神經機制尚有待釐清。本研究利用一種用於改善阿茲海默症臨床的非競爭型N-甲基-D-天門冬胺酸受體拮抗劑memantine,檢測其對於大白鼠在不同時距相關操作式制約行為及空間工作記憶行為之影響效果。實驗一為針對時間屬性的操作式制約行為實驗,運用大白鼠的區辯性增強低頻反應作業(DRL 10秒行為)與固定時距作業(FI 30秒行為)之行為作業,並操弄連續訓練與間歇訓練的兩種不同模式,測試memantine對前述四組受試的操作式制約行為在表現、消除與自發恢復等三階段之劑量反應。實驗二利用配對性延遲T迷津作業區分出不等基準線(表現好與表現差)之受試,再加以藥理實驗,測試memantine對於前述兩組受試之劑量反應。實驗一結果顯示,受試在兩種不同訓練模式下經十五次習得訓練後,在兩種操作式壓桿行為的壓桿反應相關指標中都有明顯的差異,這證實不同的行為訓練模式會導致學習後的表現有差異之別。memantine藥理實驗結果顯示,此藥對於上述四組受試的操作式行為之三階段的影響效果,會因為不同訓練模式與不同作業而異。實驗二結果顯示,memantine提高空間工作記憶的正確率在表現不好的組別有很顯著的藥效,這證實memantine對於空間式工作記憶行為的影響,也會因學習基準線的不同水平而異。在行為實驗後所進行的蛋白質表現量檢測中,memantine(5 mg/kg)只對五個測試腦區中的背側紋狀體中ERK1磷酸化程度有明顯上升的影響,而其對ERK2及CREB的磷酸化在所有腦組織中皆沒有顯著的影響。綜合以上結果,memantine影響時間與空間屬性的相關行為之藥理效果,會依行為的不同習得歷程(或行為背景經驗)及基準線表現程度而異,而此項行為藥理效果,可能與紋狀體中ERK1的磷酸化有關。 / The neural basis of cognitive enhancement is one of the intriguing topics in neuroscience research; however, the underlying neural mechanisms remain to be elucidated. This study examined the effects of memantine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist which is used to treat Alzheimer’s disease in clinic, on operant behaviors and spatial working memory. In Experiment 1, using the differential reinforcement for low-rate-response 10 sec (DRL 10s) and the fixed-interval 30 sec (FI 30s) operant tasks, and with the manipulation of two different training regimens (continuous vs. intermittent) in the acquisition phase, the effects of memantine were evaluated in three stages of behavioral tests including the performance (right after the end of 15-day acquisition), the extinction, and the spontaneous recovery (after the extinction). In Experiment 2, memantine were tested in the subjects with different level of baseline performance (good vs. bad) on the distinctive patterns of operant responding in four different groups which received DRL 10s and FI 30s with different training regimens; indicating that behavioral task and training background are critical to the operant performance of temporal operant behaviors. Such behavioral outcomes led the dissociable effects of memantine appeared in between the four groups as tested in all three different stages. The results of Experiment 2 showed a profound improvement of the correct responses rate on spatial working memory in the low-baseline group as compared to the higher-baseline group. With a pretreatment of memantine (5 mg/kg), brain tissues in five selected areas were collected for western blot assays of ERK 1, ERK 2, and CREB. The results only revealed a significant increase of ERK 1 phosphorylation in the dorsal striatum. Together, the effects of memantine to improve cognition-associated processes in the temporal operant behaviors and the baseline of performance, and the present observation of cognition-enhancing effects of memantine may be resulted by the ERK 1 phosphorylation in the dorsal striatum.
479

Investigating the porphyrias through analysis of biochemical pathways.

Ruegg, Evonne Teresa Nicole January 2014 (has links)
ABSTRACT The porphyrias are a diverse group of metabolic disorders arising from diminished activity of enzymes in the heme biosynthetic pathway. They can present with acute neurovisceral symptoms, cutaneous symptoms, or both. The complexity of these disorders is demonstrated by the fact that some acute porphyria patients with the underlying genetic defect(s) are latent and asymptomatic while others present with severe symptoms. This indicates that there is at least one other risk factor required in addition to the genetic defect for symptom manifestation. A systematic review of the heme biosynthetic pathway highlighted the involvement of a number of micronutrient cofactors. An exhaustive review of the medical literature uncovered numerous reports of micronutrient deficiencies in the porphyrias as well as successful case reports of treatments with micronutrients. Many micronutrient deficiencies present with symptoms similar to those in porphyria, in particular vitamin B6. It is hypothesized that a vitamin B6 deficiency and related micronutrient deficiencies may play a major role in the pathogenesis of the acute porphyrias. In order to further investigate the porphyrias, a computational model of the heme biosynthetic pathway was developed based on kinetic parameters derived from a careful analysis of the literature. This model demonstrated aspects of normal heme biosynthesis and illustrated some of the disordered biochemistry of acute intermittent porphyria (AIP). The testing of this model highlighted the modifications necessary to develop a more comprehensive model with the potential to investigated hypotheses of the disordered biochemistry of the porphyrias as well as the discovery of new methods of treatment and symptom control. It is concluded that vitamin B6 deficiency might be the risk factor necessary in conjunction with the genetic defect to trigger porphyria symptoms.
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Generic design and investigation of solar cooling systems

Saulich, Sven January 2013 (has links)
This thesis presents work on a holistic approach for improving the overall design of solar cooling systems driven by solar thermal collectors. Newly developed methods for thermodynamic optimization of hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show an 81% increase of the Solar Cooling Efficiency (SCEth) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSEth) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSEth with the already established COPth of the chiller, leads to the SCEth factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. Furthermore, the definition of a coefficient of performance, including irreversibilities from energy conversion (COPcon), enables a direct comparison of compression and sorption chiller technology. This new performance metric is applicable to all low-temperature heat-supply machines for direct comparison of different types or technologies. The achieved findings of this work led to an optimized generic design for solar cooling systems, which was successfully transferred to the market.

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