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Spectroscopic analysis of exoplanet atmospheres : Ground-based high-resolution atmospheric characterization of hot Jupiters using near infrared spectroscopyStoltz Årevik, Emelie January 2015 (has links)
This report is exploring the possibility of characterizing hot Jupiter atmospheres using ground-based high-resolution spectroscopy. The ESO CRIRES infrared spectrometer is selected as the observing tool. Simulated observations are computed for known transiting systems. The properties of observations (noise, spectral coverage, resolution) are estimated with the CRIRES Exposure Time Calculator. An inverse method is used for reconstructing the transmission spectra of exoplanetary atmospheres and identifying spectral features. The possibility of using this method for non-transiting systems is examined. Three exoplanets are deemed possible to reconstruct the spectrum of. / Den här rapporten studerar möjligheten att karaktärisera heta Jupiter atmosfärer genom att använda markbaserad högupplöst spektroskopi. ESO:s CRIRES infraröda spektrometer används som observeringsvektyg. Simulerade observationer beräknas för kända system där planeten genomgår en transit. Flera aspekter kring observationer (brus, våglängdstäckning, upplösning) uppskattas med CRIRES Exposure Time Calculator. En invers metod används för att rekonstruera exoplanetatmosfärers transmissionsspektrum och för att identifiera spektraldrag. Möjligheten att använda den här metoden för system utan transit utforskas. Tre exoplaneter antas vara möjliga att rekonstruera spektrat från.
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Paleolimnological assessment of environmental changes occurring on Pim Island, Nunavut, High Arctic CanadaROUILLARD, ALEXANDRA 23 December 2010 (has links)
Despite the documented sensitivity of polar environments, long-term monitoring data are especially sparse in these regions. Diatom-based paleolimnology has contributed significantly to understanding the response of Arctic lakes to climate change, but most studies have been conducted in regions with relatively high lakewater buffering capacity. As such, Pim Island (Nunavut, Canada) is a region of limnological interest because, due to the local geology, its surface waters are of relatively lower pH and previous research suggests that such softwater lakes may be especially responsive to climate fluctuations and therefore provide the best paleoclimate records. This thesis has two separate but related chapters, as well as an exploratory study included in appendix. First, a novel approach using visible-near-infrared spectroscopy (VNIRS) was used to infer lakewater dissolved organic carbon (DOC), from a 160-lake calibration set from the Canadian Arctic. Historically sound and similar trends were reconstructed when compared against a Canadian diatom-based DOC and Swedish VNIRS-based total organic carbon (TOC) model on Arctic Holocene sediment records. Second, a diatom and spectroscopically-based multi-proxy approach was utilized on Holocene sedimentary records from two lakes on Pim Island to assess long-term environmental change from this region. Benthic and epiphytic diatom taxa dominated the pre-19th century assemblages, although marked shifts in dominant species were recorded during the mid-Holocene. The mid-Holocene diatom assemblages underwent an abrupt ecological shift from alkaliphilous Fragilaria sensu lato to slightly acidophilous Achnanthes and Navicula. The post-19th century was characterized by an increase in the planktonic species (Cyclotella radiosa), indicating marked lakeice reductions. Third, the limnological properties and modern diatom assemblages of ponds and lakes surveyed from 1979 to 2009 on Pim Island were examined as part of an exploratory study. The ponds and lakes displayed typical characteristics observed in high Arctic lacustrine environments (i.e. oligotrophic, very dilute) but with overall relatively low alkalinity. Poorly-buffered sites had diatom assemblages that were distinct from well-buffered lakes elsewhere in the High Arctic. Our findings contribute to an improved understanding of the interactions between local environments and limnological changes, and also provide insight on the biological responses of lakes to Holocene environmental change and allow us to compare responses to those in more alkaline sites. / Thesis (Master, Biology) -- Queen's University, 2010-12-22 19:53:45.03
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INFLUENCE OF TISSUE ABSORPTION AND SCATTERING ON DIFFUSE CORRELATION SPECTROSCOPY BLOOD FLOW MEASUREMENTSIrwin, Daniel 01 January 2011 (has links)
This investigation evaluates the influences of optical property assumptions on nearinfrared diffuse correlation spectroscopy (DCS) flow index measurements. Independent variation is induced in optical properties, absorption coefficient (μa) and reduced scattering coefficient (μs’), of liquid phantoms with concurrent measurements of flow indices. A hybrid instrument is incorporated consisting of a dual-wavelength (785 and 830 nm) DCS flow device to obtain flow indices and a frequency-domain tissue-oximeter for optical properties. Flow indices are calculated with measured μa and μs’ or assumed constant μa and μs’. Inaccurate μs’ assumptions produced much larger flow index errors than inaccurate μa. Underestimated/overestimated μs’ from -35%/+175% lead to flow index errors of +110%/-80% and underestimated/overestimated μa from -40%/+150% lead to -20%/+40%, regardless of wavelength. Analysis of a clinical study involving human head and neck tumors indicates flow index errors due to inter-patient optical property variations up to +280%. Collectively, these findings suggest that studies involving significant μa and μs’ changes should measure flow index and optical properties simultaneously to accurately extract blood flow information. This study provides unique insight through the use of liquid phantoms, hybrid instrumentation, incorporation of measurement errors and a generalization into DCS flow index errors due to the influences of optical properties.
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Raman and near infrared spectroscopic analysis of amniotic fluid : metabolomics of maternal and fetal health indicatorsPower, Kristin Marie. January 2007 (has links)
This thesis presents quantitative tools for the metabolomic analysis of amniotic fluid (AF) using vibrational spectroscopy. A total of 300 AF samples were collected for this retrospective cohort study and both Raman and near infrared (NIR) spectra were measured. Spectral data was compressed using a Haar wavelet transform and stage-wise multilinear regression (MLR). Calibration models were calculated for glucose, lactate and uric acid concentrations in AF. Birth weight, gestational diabetes mellitus (GDM) and gestational age were classified with the resulting compressed Raman and NIR spectra, using a genetic algorithm (GA) and a cross-validation approach. Results show that both Raman and NIR spectra of AF were not able to estimate the concentrations of glucose, lactate or uric acid with high precision. However, metabolomic analysis of AF Raman and NIR spectra was capable of estimating the development of GDM, abnormal birth weights as well as gestational ages with sensitivities >75% and specificities >77%. In addition, Raman and NIR metabolomic profiles showed a statistical difference in patients delivering preterm. Of the two spectroscopic analyses studied, NIR spectroscopy of AF has the potential to become a robust and non-invasive diagnostic tool for maternal and fetal health.
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Development of an Optical Brain-computer Interface Using Dynamic Topographical Pattern ClassificationSchudlo, Larissa Christina 26 November 2012 (has links)
Near-infrared spectroscopy (NIRS) in an imaging technique that has gained much attention in brain-computer interfaces (BCIs). Previous NIRS-BCI studies have primarily employed temporal features, derived from the time course of hemodynamic activity, despite potential value contained in the spatial attributes of a response. In an initial offline study, we investigated the value of using joint spatial-temporal pattern classification with dynamic NIR topograms to differentiate intentional cortical activation from rest. With the inclusion of spatiotemporal features, we demonstrated a significant increase in achievable classification accuracies from those obtained using temporal features alone (p < 10-4). In a second study, we evaluated the feasibility of implementing joint spatial-temporal pattern classification in an online system. We developed an online system-paced NIRS-BCI, and were able to differentiate two cortical states with high accuracy (77.4±10.5%). Collectively, these findings demonstrate the value of including spatiotemporal features in the classification of functional NIRS data for BCI applications.
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Sources and Fates of Dissolved Organic Carbon in Rural and Urban Watersheds in Brazos County, TexasCioce, Danielle 2012 August 1900 (has links)
The Bryan/College Station (B/CS) region has been reported to have elevated concentrations of dissolved organic carbon (DOC) in surface water. Increased DOC concentrations are worrisome as DOC has been shown to be an energy source for the recovery and regrowth of E. coli and many watersheds are impaired by high bacteria levels. To examine the sources and fates of DOC in rural and urban regions to better understand DOC movement though the environment, seven watersheds were studied. To investigate source, streams were analyzed using diffuse reflectance near infrared spectroscopy (DR-NIR) and carbon isotopes. Fate of DOC was determined through monthly streams samples, gathered between March 2011 and February 2012, which were incubated for biodegradable DOC (BDOC). Soil in the region was sampled based on land use categories. Soil was analyzed for DOC and BDOC as well as DOC adsorption, the other major fate of DOC. Above ground vegetation was sampled in conjunction with soil and analyzed for BDOC.
Data indicated that fecal matter from cliff swallows provided considerable organic material to streams in the B/CS region as shown through DR-NIR. Carbon isotope values in streams ranged from -23.5 +/- 0.7% to -26.8 +/- 0.5%. Stream spectra may be able to predict carbon isotope values in streams (Adj. R2 = 0.88). Mean annual stream DOC concentrations ranged from 11 +/- 3 mg/L to 31 +/- 12 mg/L, which represents a significant decrease in DOC between 2007 and 2011. Concurrent increases in pH and conductivity were also recorded. The decrease in DOC and the increases in pH and conductivity may be due to impacts of high sodium irrigation tap water. Biodegradable DOC was low in streams, which is likely due to DOC being present in streams in refractory forms that are resistant to microbial breakdown. Soil chemistry, including soil adsorption, was greatly influenced by sodium. The elevated adsorption coefficients and release values seen in highly developed and urban open areas can be attributed to frequent exposure to high sodium irrigation water. The results indicate that sodium is a major driver of DOC in the system. Sound management decisions concerning irrigation water chemistry and urban development might eventually emerge to protect water quality as a result of this research.
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Monitoring muscle oxygenation and myoelectric activity after damage-inducing exerciseAhmadi, Sirous January 2007 (has links)
Doctor of Philosophy / In this thesis, three experiments were conducted to monitor: (i) muscle oxygenation and electromyographic activity of the biceps brachii after exercise-induced muscle damage (ii) muscle oxygenation after downhill walking-induced muscle damage, and, (iii) muscle oxygenation following a bout of vigorous concentric exercise. Maximal eccentric exercise (EE) of biceps brachii resulted in significantly increased mean resting oxygen saturation and decreased deoxyhaemoglobin. During isometric contractions at 50% and 80% of subjects’ maximum voluntary torque (MVT), oxygen desaturation and resaturation kinetics and volume were significantly decreased after EE, and these declines were significantly prevalent over the following 6 days. Additionally, a significant shift in median frequency intercept (measured by electromyography; EMG) towards lower frequencies was observed during isometric contractions at both 50% and 80% MVT after EE in the exercised arm. After an exhaustive session of downhill walking, another form of EE, resting total haemoglobin and oxyhaemoglobin decreased. Furthermore, during isometric contractions at 30%, 50% and 80% of MVT, prolonged and significant increases were observed in oxygen desaturation and resaturation kinetics and volumes after ambulatory EE. In contrast to the two EE experiments, concentric contractions did not evoke any prolonged changes in muscle oxygenation. Collectively, the findings of this thesis revealed significant and prolonged changes in muscle oxygenation at rest and during exercise, following sessions of strenuous eccentric exercise. Although not clear, the possible mechanism responsible for the changes in muscle oxygenation after EE could be increased resting muscle oxygen utilization due to probable muscle damage and a subsequent requirement of energy demanding repair processes. Concentric exercise resulted in fatigue, but it did not affect muscle oxygenation. Although a prolonged reduction in EMG median frequency intercept was observed after EE, this was not closely time-associated with the biochemical, anthropometric or functional markers of muscle damage.
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Spectroscopic instrumentation for process analytical chemistry /Aldridge, Paul K. January 1991 (has links)
Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [131]-137).
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Application of process analytical technology to wood a near infrared spectroscopy approach /Adedipe, Oluwatosin Emmanuel. January 2008 (has links)
Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xi, 98 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 47-52).
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Pattern recognition methods for the analysis of infrared imaging data and multivariate calibration standardization for near-infrared spectroscopyZhang, Lin. January 2002 (has links)
Thesis (Ph.D.)--Ohio University, March, 2002. / Title from PDF t.p.
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