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Abstract: We propose a new application of inexpensive light‐emitting diode (LED)‐based Sun photometers, consisting of measuring the aerosol optical thickness (AOT) with high resolution within metropolitan scales. Previously, these instruments have been used at continental scales by the GLOBE program, but this extension is already covered by more expensive and higher‐precision instruments of the AERONET global network. For this we built an open source two‐channeled LED‐based Sun photometer based on previous developments, with improvements in the hardware, software, and modifications on the calibration procedure. Among these we highlight the use of MODTRAN to characterize the effect introduced by using LED sensors in the AOT retrieval, an open design available for the scientific community and a calibration procedure that takes advantage of a CIMEL Sun photometer located within the city, enables the intercomparison of several LED Sun photometers with a common reference. We estimated the root‐mean‐square error in the AOT retrieved by the prototypes as 0.006 at the 564 nm and 0.009 at the 408 nm. This error is way under the magnitude of the AOT daily cycle variability measured by us in our campaigns, even for distances closer than 15 km. In addition to inner city campaigns, we also show aerosol‐tracing applications by measuring AOT variations from the city of Santiago to the Andes glaciers. Measuring AOT at high spatial resolution in urban areas can improve our understanding of urban scale aerosol circulation, providing information for solar energy planning, health policies, and climatological studies, among others. [ABSTRACT FROM AUTHOR]

Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here we argue that some of the criticism is not warranted. In particular, the criticism related to cirrus clouds being an "end member" case of possible clouds depends heavily on models that may have an inadequate representation of cirrus clouds. Present climate observations show that thin cirrus clouds (optical depth less than 10) can produce positive cloud radiative forcing. When this forcing is represented in models, resulting cirrus clouds are not necessarily realistic. Therefore, cirrus clouds that have a radiative forcing consistent with present climate observations, can provide a solution to the faint young sun paradox, or at least ease the amount of CO2 or other greenhouse substances needed to provide temperatures above freezing during the Archean. [ABSTRACT FROM AUTHOR]

The effects of short term intravenous administration of gallopamil on coronary haemodynamic variables were studied in 10 patients with stable exertional angina and angiographically confirmed coronary artery disease that affected the proximal portion of the left anterior descending artery. Blood flow in the great cardiac vein was measured by a thermodilution technique, both at rest and during ischaemia induced by atrial pacing, before and after intravenous administration of gallopamil (0.02 mg/kg as a bolus dose given over three minutes, followed by an infusion of 0.0005 mg/kg/min). Gallopamil significantly prolonged the mean (SD) duration of pacing that was tolerated (11 (2.6) vs 14.8 (2.4] min, significantly increased the mean (SD) peak heart rate attained during pacing (142 (15) vs 158 (11) beats/min), and reduced mean (SD) arterial pressure (133 (17) vs 116 (17) mm Hg). There were no changes in mean (SD) blood flow in the great cardiac vein (134.1 (57) vs 112.9 (38) ml/min, mean (SD) anterior regional coronary resistance (1.18 (0.6) vs 1.15 (0.5) mm Hg/ml/min), and mean (SD) anterior regional myocardial oxygen consumption (16.6 (6) vs 13.7 (4) ml/min). These data confirm that gallopamil is an effective antianginal agent and suggest that a reduction of myocardial oxygen demand is the predominant mechanism by which the drug exerts its beneficial effects. [ABSTRACT FROM PUBLISHER]

Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here, we argue that: (1) climates having a lower than present mean surface temperature cannot be discarded as solutions to the faint young sun paradox, (2) the detrainment from deep convective clouds in the tropics is a well-established physical mechanism for the formation of high clouds that have a positive radiative forcing (even if the possible role of these clouds as a negative climate feedback remains controversial) and (3) even if some cloud properties are not mutually consistent with observations in radiative transfer parameterizations, the most relevant consistency (for the purpose of hypothesis testing) is with observations of the cloud radiative forcing. Therefore, we maintain that cirrus clouds, as observed in the current climate and covering a large region of the tropics, can provide a solution to the faint young sun paradox, or at least ease the amount of CO2 or other greenhouse substances needed to provide temperatures above freezing during the Archean. [ABSTRACT FROM AUTHOR]

Introduction: Anterior glenohumeral bone loss reconstruction reduces failure rates after soft tissue surgery in patients with large glenoid bone defects. Multiple bone block techniques have been described, most with metal hardware fixation. The objective of this study is to evaluate the safety, as well as the short-term functional and radiological results of an arthroscopic bone block metal-free fixation or bone block cerclage., Material and Methods: Retrospective study of patients with glenohumeral instability and>15% glenoid bone loss operated during 2019 with follow-up of at least 12 months. Radiography and computerized tomography studies were performed. Functional outcomes were evaluated before and after surgery with the Western Ontario Shoulder Instability Index and Rowe score., Results: A total of 21 patients with a median age of 30.6 (SD 7.1) were included. All showed radiographic consolidation at 3 months follow-up. A percentage of 90.4 of bone grafts presented osteolysis at peripherical areas and 95.2% revealed consolidation in the areas with contact to the glenoid. The median glenoid estimated surface went from 79.3% before surgery to 98.4% at 12 months. Functional scores were statically significant (P<.001) for Western Ontario Shoulder Instability Index (35.6-86.9) and Rowe score (25.2 to 96.4). No serious complications were reported., Conclusion: The bone block cerclage is a safe, metal-free technique that achieves total consolidation of the bone graft and favorable functional and radiological outcomes at 12 months follow-up., (Copyright © 2021 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.)