Active rifts release large amounts of gases from deep sources to the atmosphere by advection and diffusion processes along permeable fracture zones. The objective of this study is to develop ...geothermal exploration concepts for areas with little or no hydrothermal surface expressions suitable for fluid sampling and analyses (e.g., hot springs, geysers, and fumaroles). In such areas, soil gas surveys can complement established geophysical and geochemical exploration. We report CO2, 222Rn (radon), and 220Rn (thoron) emission data and ground temperatures from the Aluto volcanic complex in the Main Ethiopian Rift to improve understanding of tectonic and volcanic controls on the existing geothermal system. This suite of gas emission measurements allows us to identify major, deep‐rooted permeable structures with active fluid circulation and identify suitable drilling targets for geothermal production wells on Aluto. We show that significant differences in gas signatures (i.e., efflux and spatial pattern) can be used to identify predominantly volcanically and/or tectonically influenced compartments. Major gas emissions indicate significant fluid circulation at depth, which is typical for magmatic systems. Such high gas emissions have been observed in areas affected by major tectonic structures interacting with magmatic bodies at depth (tectono‐volcanic). Predominantly fault‐controlled sectors also show hydrothermal fluid circulation, but to a lower extent compared to tectono‐volcanic sectors. Within the Aluto volcanic complex, geothermal production wells mainly target such fault‐controlled domains, whereas results of the study indicate strongest fluid circulation in tectono‐volcanic sectors. This result should be considered for the future exploration and development strategy of the site.
Plain Language Summary
Active rifts release large amounts of gases from deep sources to the atmosphere along permeable fracture zones. We report CO2, 222Rn (radon), and 220Rn (thoron) emission data and ground temperatures from the Aluto volcanic complex in the Main Ethiopian Rift. Results help to improve understanding of tectonic and volcanic controls on the existing geothermal system and are useful to identify suitable drilling targets for geothermal production wells. Variations in gas emissions also allow mapping of permeable structures, even in areas where faults are not obvious. We show that significant differences in gas signatures (i.e., flow rates and spatial pattern) can be used to identify predominantly volcanically and/or tectonically influenced domains. Emissions increase toward the volcanic center implying a deep degassing magmatic body.
Key Points
First complete set of CO2‐222Rn‐220Rn gas emission data from the Main Ethiopian Rift is reported
Volatile emissions focus along volcanic and tectonic structures and allow mapping of deep gas sources across the Aluto volcano, Ethiopia
Emissions increase toward the volcanic centre, implying a degassing magmatic body
Measurement of GFR is important for the management of chronic kidney disease (CKD). Although bolus administration of radiocontrast agents is commonly used to measure GFR, the optimal duration of ...sampling to assess their plasma clearance is unknown. The purpose of this study was to evaluate whether the duration of plasma sampling influences precision and estimation of GFR.
GFR was measured by sampling plasma 12 times over 5 h in 56 patients with CKD (mean age 64 yr, 98% men, 79% Caucasian, 34% diabetics, estimated GFR 31.8 +/- 14.2 ml/min/1.73 m(2)). In a subset of 12 patients we measured GFR by sampling plasma 17 times over 10 h.
Short sampling intervals considerably overestimated GFR measured using total plasma iothalamate clearance, especially in larger patients. In the higher estimated GFR group (>30 ml/min/1.73 m(2)), the 5-h GFR was 17% higher and 2-h GFR 54% higher compared with the 10-h GFR, which averaged 40.3 ml/min/1.73 m(2). In the lower estimated GFR group (<30 ml/min/1.73 m(2)), the 5-h GFR was 36% higher and 2-h GFR 126% higher compared with the 10-h GFR, which averaged 22.2 ml/min/1.73 m(2). Short sampling duration also reduced the precision of the estimated GFR from 1.67% for 10-h GFR, to 3.48% for 5-h GFR, and to 7.07% for 2-h GFR.
GFR measured over a longer duration with multiple plasma samples spanning the distribution and elimination phases may improve precision and provide a better measure of renal function.
Thermal waters in the Main Ethiopian Rift Valley are characterized by high Na, bicarbonate and fluoride concentrations, and near-neutral to alkaline pH. Sodium, bicarbonate and fluoride are ...positively correlated in the waters. The principal reason for the bicarbonate in the area is the high rate of carbon dioxide outgassing. This, combined with acid volcanics, geothermal heating, low Ca and low salinity, is also one of the causes of high fluoride in this part of the active volcanic zone of the East African Rift. Evaporative concentration is responsible for the high salinity, alkalinity and fluoride in the closed-basin lakes of the region. The waters are undersaturated with respect to fluoride and anhydrite. Calcium tends to be fixed in Ca bearing minerals such as calcite and epidote, which are abundant in the system. Hence, it appears that fluoride is a mobile component in acid volcanic geothermal systems.
Les eaux thermales dans la Rift Valley principale de l'Éthiopie sont caractérisées par des teneurs élevées en Na, bicarbonate et fluorure et des pH quasi neutres à alcalins. Dans les eaux le Na, le bicarbonate et les fluorures montrent une corrélation positive. La source principale du bicarbonate dans la région est le taux élevé de dégazage en gaz carbonique. Celui-ci, combiné à la présence d'un volcanisme acide, d'un échauffement géothermique et de faibles teneurs en sels, en particulier en Ca, est également une des causes des teneurs élevées en fluorures dans cette partie de la zone volcanique active du Rift est-africain. La concentration par évaporation explique la salinité élevée, l'alcalinité et les teneurs en fluorures dans les lacs de dépressions endoréiques de la région. Les eaux sont soussaturées par rapport à la fluorine et l'anhydrite. Le Ca a tendance à se fixer dans des minéraux à Ca, tels que la calcite et l'épidote, qui abondent sous ces conditions. Ainsi, il apparaît que les fluorures sont des constituants mobiles dans les systèmes géothermiques en milieu volcanique acide.
OBJECTIVES: We aimed to assess medication related quality of life (MRQOL) among elderly patients with polypharmacy at Gondar University Hospital, Gondar, Ethiopia. METHODS: A prospective cross ...sectional study was carried out among 150 elder patients in internal medicine and ambulatory wards of Gondar University hospital from March 25 to May 15 2017 using validated scale, Medication-Related Quality of Life Scale version 1.0 (MRQoLS-vl.O ). RESULTS: A total of 150 elderly patients with poly pharmacy participated in the study with a mean age 70.06 5.12 and two third of the participants (67.3%) were female. Overall prevalence of poor quality of life due to polypharmacy in the current study was found to be 75.3% of the participants. Regarding severity of impairment in MRQoL, Univariate analysis revealed that frequency of hospital visits (COR=1.34, 95% CI, 1.02-1.77) and number of medications (COR =1.94, 95% CI, 1.33, 2.8) had statistically significant positive association with the likelihood of having sever impairment. The multivariate analysis also showed that one unit increase in the number of hospital visits (AOR =1.45,95% CI, 1.040-2.024) and medications greater than 5 (AOR =1.91,95% CI, 1.29,2.84) increases 1.45 and 1.91 times the likely hood of posing severe impairment of MRQoL, respectively. As far as poor MRQoL quality of life is concerned multivariate analysis didn't show any significant association between the poor MRQoL, and Sociodemographic and clinical data of patients. CONCLUSIONS: The overall prevalence of poor quality of life due to poly pharmacy was 75.3% that implies poly pharmacy results poor quality of life in elder patients. Frequency of hospital visit and number of medication was the independent predictors for severe impairment in MRQoL. This study needs further investigation to see the correlation between independent variables and dependent outcomes. Deprescribing aiming at minimizing inappropriate poly pharmacy should be sought by physicians in elderly patients.
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