New insights into the flow dynamics of a deep freshwater aquifer in the semi-arid and saline Cuvelai-Etosha Basin, Northern Namibia: Results of a multi-environmental tracer study

Study region: A paleo-megafan system of the Cubango River in the northern parts of the semi-arid Cuvelai-Etosha Basin, shared by Angola and Namibia. It hosts a deep freshwater aquifer, the so-called Kalahari-Ohangwena 2 (KOH-2), with the potential to resolve the imminent regional water supply shortages. Study focus: Hydrogeochemical and multi-environmental tracer studies incorporating the use of age tracers ¹⁴C, ³⁶Cl, ⁸¹Kr and ⁴He to determine the age of groundwater and provide insights into the flow dynamics of the KOH-2. New hydrological insights for the region: Stable water isotopes and noble gas thermometry show that in a period with higher rainfall and recharge, temperatures were at least 3 – 4 °C lower than today. Several arguments led to the conclusion that younger groundwater, possibly of an age of 35,000 years, is mixed with ancient saline pore water. These include: 1) the correlation of measured ³⁶Cl and ⁸¹Kr ratios, as well as ⁴He concentrations, using a binary mixing model, and 2) the substantial variation in ⁸¹Kr ages, ranging from 40,000 to 170,000 years, over relatively short distances—a phenomenon challenging to explain by advective groundwater flow equations. Consequently, the ages derived from ⁸¹Kr measurements serve as indicators of the extent of freshening and therefore describe mixing ages rather than absolute travel times.ISSN:2214-581

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes

Outcomes in Newly Diagnosed Atrial Fibrillation and History of Acute Coronary Syndromes: Insights from GARFIELD-AF

BACKGROUND: Many patients with atrial fibrillation have concomitant coronary artery disease with or without acute coronary syndromes and are in need of additional antithrombotic therapy. There are few data on the long-term clinical outcome of atrial fibrillation patients with a history of acute coronary syndrome. This is a 2-year study of atrial fibrillation patients with or without a history of acute coronary syndromes