Exploring new approaches to understanding channel width and erosion rates in bedrock rivers, Puerto Rico, USA

Includes bibliographical references.2022 Fall.Earth system dynamics produce constant adjustments to sea level, tectonics, and climate. Bedrock rivers communicate these changes throughout mountains by driving landscape and erosional responses that facilitate topographic change. It follows that an improved understanding of bedrock rivers can help us better model and reconstruct the interplay of changes to base level, uplift, and climate from landscapes. Although bedrock channel width plays a first-order role in river stream power and stream power-based landscape evolution models, because of the physical challenges associated with acquiring these data, channel width is often estimated and introduces uncertainty. In addition, the lack of bedrock channel width data has limited our understanding of what factors control channel width. In this dissertation (Chapter 2), I leverage high-resolution topographic data, Mean Annual Precipitation information, and use the HEC-RAS river modeling software to remotely derive bedrock channel width at desired flow scenarios. The accuracy of modeling results is verified for rivers in Puerto Rico using USGS gauging station field measurements, as well as my own channel width field measurements associated with 1-year recurrence interval discharges. As a next step, (Chapter 3) I implement the bedrock width modeling method derived in Chapter 2 to obtain >4,000 channel width measurements from reaches across Puerto Rico. I then compare these bedrock river width values to various factors (e.g. rock type and rock strength, drainage area, Ecozone, and grain size) that have been identified in the literature to scale with or influence channel width. My analyses indicate that, in Puerto Rico, rock type is a dominant control of bedrock channel width in small (≤6-10 km2) drainage areas. Contrary to patterns of rock strength and bedrock width documented in the literature (e.g. Montgomery and Gran, 2001), I find that width doesn't appear to correlate with proxies for bedrock channel strength. Strong granodiorites have the widest low-order channels and the strong volcaniclastics and weak serpentinites have comparably narrow low-order channels. Analysis of limited grain size measurements shows a discernable difference in the coarse grain size distribution between the three rock types, with the volcaniclastic and serpentinite draining rivers having coarser sediment than granodiorite draining streams. These findings suggest that bedrock channel width may be influenced by unmeasured lithological parameters that impact the size of grains delivered to river channels from adjacent hillslopes (i.e. rock fracture density and spacing, as well as weathering). Lastly, (Chapter 4) I spatially analyze in-situ cosmogenic nuclide (10Be in quartz and 36Cl in magnetite) concentrations and find that bedrock erosion rates are higher in the central part of Puerto Rico than toward the east. Analysis of erosion rates compared to other parameters reveals that channel steepness, rather than precipitation or rock type, is positively associated with erosion rates. I further apply these erosion rate data to test the accuracy of four incision models of varying complexity. Model comparisons reveal that drainage area is a better predictor of incision rates in Puerto Rico than a precipitation-weighted drainage area parameter. In addition, whereas an increase in model complexity slightly improves model performance, the model only explains ~35% of the variability in erosion rates. It follows that current incision models are still missing many controlling factors of river incision rates in Puerto Rico

Microfield Fluctuations and Spectral Line Shapes in Strongly Coupled Two-Component Plasmas

The spectral line shapes for hydrogen-like heavy ion emitters embedded in strongly correlated two-component electron-ion plasmas are investigated with numerical simulations. For that purpose the microfield fluctuations are calculated by molecular dynamics simulations where short range quantum effects are taken into account by using a regularized Coulomb potential for the electron-ion interaction. The microfield fluctuations are used as input in a numerical solution of the time-dependent Schroedinger equation for the radiating electron. In distinction to the standard impact and quasistatic approximations the method presented here allows to account for the correlations between plasma ions and electrons. The shapes of the Ly-alpha line in Al are investigated in the intermediate regime. The calculations are in good agreement with experiments on the Ly-alpha line in laser generated plasmas.Comment: 5 figure

Relevance of maternal sodium level for preeclampsia-associated adverse pregnancy outcomes

Die Präeklampsie (PE) zählt zu den hypertensiven Schwangerschaftserkrankungen und ist weltweit eine der Hauptursachen für kindliche und mütterliche Morbidität und Mortalität. Die frühzeitige Erkennung und engmaschige Kontrolle PE-assoziierter Komplikationen besitzt daher höchste Relevanz für den klinischen Alltag. Ein Zusammenhang zwischen der maternalen Natriumserumkonzentration und PE wurde in Fallberichten beschrieben. Diese Studie soll eine Assoziation zwischen der Natriumkonzentration und PE-assoziierten Komplikationen evaluieren. Es handelt sich um eine retrospektive Analyse einer 8-Jahres Kohorte von Frauen (07/2010 – 03/2018), die sich mit klinischen Symptomen einer PE in der geburtsmedizinischen Klinik der Charité vorstellten. Frauen, bei denen ein sFlt-1/PlGF-Quotient bestimmt wurde und deren Natriumserumkonzentration ≤ 14 Tage vor der Entbindung erhoben wurde, wurden in die Untersuchung eingeschlossen. Primärer Endpunkt der Studie war das Auftreten schwerer PE-assoziierter Komplikationen (englisch adverse outcome (AO)). Zu den maternalen AOs zählten das Auftreten eines HELLP-Syndroms, Nierenversagens, Lungenödems, einer disseminierten intravasalen Koagulopathie, Hirnblutung, Eklampsie oder des mütterlichen Todes. Fetale und neonatale Komplikationen waren definiert durch das Auftreten eines Atemnotsyndroms, einer intraventrikulären Hirnblutung, nekrotisierenden Enterokolitis, Entbindung vor der 34. SSW aufgrund einer Präeklampsie, vorzeitigen Plazentalösung oder des intrauterinen/bis 7 Tage nach der Geburt eingetretenen kindlichen Todes. Von insgesamt 198 Patientinnen entwickelten n=88 (44.4%) ein AO. Insgesamt konnte bei 2% der Patientinnen eine Hyponatriämie ≤ 130 mmol/l nachgewiesen werden und die Natriumkonzentration war in der Gruppe mit einem AO geringer als in der Gruppe ohne AO (136 mmol/l zu 137 mmol/l). Außerdem korrelierte die Natriumkonzentration negativ mit dem sFlt-1/PlGF-Quotienten (r= -0.19, 95% Konfidenzintervall (CI): -0.31 – -0.05). Unsere Analyse ergab eine signifikante Assoziation zwischen einer sinkenden Natriumkonzentration und der Entwicklung eines AOs. Ein Anstieg der Natriumkonzentration um 1 mmol/l reduzierte das Risiko ein AO zu entwickeln um 21% (Odds ratio: 0.79, 95% CI: 0.67 – 0.93, p=0.01). Zudem erwies sich ein Anstieg der Natriumkonzentration als protektiver Effekt auf die Zeit bis zur Entbindung. Unsere Studie offenbart, dass die Hyponatriämie eine seltene Komplikation der PE darstellt. Es wurde erstmals eine negative Korrelation der Natriumkonzentration zum sFlt-1/PlGF-Quotienten dargelegt. Außerdem konnte erstmalig ein Zusammenhang der Natriumkonzentration sowohl zur Entwicklung eines AOs als auch zur verbleibenden Zeit bis zur Entbindung beobachtet werden. Wir schlussfolgern, dass die Bestimmung der Natriumkonzentration und mögliche Integration in Vorhersagemodelle zur Risikostratifizierung PE-assoziierter Komplikationen sinnvoll sein kann.Preeclampsia (PE) is one of the leading causes for fetal and maternal morbidity and mortality worldwide. Therefore, early detection and close monitoring of patients with PE and PE-associated complications has an immense relevance for the clinical routine. An association of sodium concentration and PE has already been described in several case reports. This study thus investigated the impact of the sodium concentration has on the development of PE-associated complications in high-risk-patients with suspected PE. This study is a retrospective real-world analysis of an 8-year cohort of women (07/2010 – 03/2018) who presented with clinical symptoms of PE. Women with available sFlt-1/PlGF ratio and with existing sodium level ≤ 14 days prior to delivery were included in the study. The primary endpoint of the study was not the diagnosis of a PE, but the presence of severe PE-associated adverse maternal or fetal outcomes (AO). Maternal AOs comprise HELLP-syndrome, renal failure, pulmonary edema, disseminated intravascular coagulation, cerebral hemorrhage, eclampsia and maternal death. Fetal and neonatal complications were defined by the occurrence of a respiratory distress syndrome, intraventricular cerebral hemorrhage, necrotizing enterocolitis, delivery prior to 34 weeks of pregnancy due to PE, placental abruption and intrauterine death up to neonatal death 7 days postnatum. Of 198 patients in total, 88 patients (44.4%) developed an AO. Overall, 2% of patients had a hyponatremia ≤ 130 mmol/l and the median sodium concentration was lower in the group where an AO occurred than in the group without an AO (136 mmol/l vs. 137 mmol/l). Moreover, sodium concentration was negatively correlated to the sFlt-1/PlGF ratio (r= -0.19, 95% confidence interval (CI): -0.31 – -0.05). Our analysis showed a significant association between sodium concentration and the development of an AO. An increase in sodium concentration by 1 mmol/l reduced the risk of developing an AO by 21% (Odds ratio: 0.79, 95% CI: 0.67 – 0.93, p=0.01). Furthermore, we found that an increase in sodium concentration had a protective effect on time to delivery. Our study demonstrated that hyponatremia is a rare complication of PE. We were able to show a negative correlation between the sodium concentration and the sFlt-1/PlGF ratio. Secondly, we demonstrated an association between the sodium concentration and both, the development of an AO and the time remaining to delivery. We therefore recommend to integrate the measurement of sodium concentration into multimarker prediction models, which can be useful for risk stratification of PE-associated complications

Detection of virgin olive oil adulteration using low field unilateral NMR

The detection of adulteration in edible oils is a concern in the food industry, especially for the higher priced virgin olive oils. This article presents a low field unilateral nuclear magnetic resonance (NMR) method for the detection of the adulteration of virgin olive oil that can be performed through sealed bottles providing a non-destructive screening technique. Adulterations of an extra virgin olive oil with different percentages of sunflower oil and red palm oil were measured with a commercial unilateral instrument, the profile NMR-Mouse. The NMR signal was processed using a 2-dimensional Inverse Laplace transformation to analyze the transverse relaxation and self-diffusion behaviors of different oils. The obtained results demonstrated the feasibility of detecting adulterations of olive oil with percentages of at least 10% of sunflower and red palm oils