Spatio-temporal evaluation of air pollution using ground-based and satellite data during COVID-19 in Ecuador.

The concentration of gases in the atmosphere is a topic of growing concern due to its effects on health, ecosystems etc. Its monitoring is commonly carried out through ground stations which offer high precision and temporal resolution. However, in countries with few stations, such as Ecuador, these data fail to adequately describe the spatial variability of pollutant concentrations. Remote sensing data have great potential to solve this complication. This study evaluates the spatiotemporal distribution of nitrogen dioxide (NO2) and ozone (O3) concentrations in Quito and Cuenca, using data obtained from ground-based and Sentinel-5 Precursor mission sources during the years 2019 and 2020. Moreover, a Linear Regression Model (LRM) was employed to analyze the correlation between ground-based and satellite datasets, revealing positive associations for O3 (R2 = 0.83, RMSE = 0.18) and NO2 (R2 = 0.83, RMSE = 0.25) in Quito; and O3 (R2 = 0.74, RMSE = 0.23) and NO2, (R2 = 0.73, RMSE = 0.23) for Cuenca. The agreement between ground-based and satellite datasets was analyzed by employing the intra-class correlation coefficient (ICC), reflecting good agreement between them (ICC ≥0.57); and using Bland and Altman coefficients, which showed low bias and that more than 95% of the differences are within the limits of agreement. Furthermore, the study investigated the impact of COVID-19 pandemic-related restrictions, such as social distancing and isolation, on atmospheric conditions. This was categorized into three periods for 2019 and 2020: before (from January 1st to March 15th), during (from March 16th to May 17th), and after (from March 18th to December 31st). A 51% decrease in NO2 concentrations was recorded for Cuenca, while Quito experienced a 14.7% decrease. The tropospheric column decreased by 27.3% in Cuenca and 15.1% in Quito. O3 showed an increasing trend, with tropospheric concentrations rising by 0.42% and 0.11% for Cuenca and Quito respectively, while the concentration in Cuenca decreased by 14.4%. Quito experienced an increase of 10.5%. Finally, the reduction of chemical species in the atmosphere as a consequence of mobility restrictions is highlighted. This study compared satellite and ground station data for NO2 and O3 concentrations. Despite differing units preventing data validation, it verified the Sentinel-5P satellite's effectiveness in anomaly detection. Our research's value lies in its applicability to developing countries, which may lack extensive monitoring networks, demonstrating the potential use of satellite technology in urban planning.

Spatio-temporal patterns of thermal anomalies and drought over tropical forests driven by recent extreme climatic anomalies.

The recent 2015-2016 El Niño (EN) event was considered as strong as the EN in 1997-1998. Given such magnitude, it was expected to result in extreme warming and moisture anomalies in tropical areas. Here we characterize the spatial patterns of temperature anomalies and drought over tropical forests, including tropical South America (Amazonia), Africa and Asia/Indonesia during the 2015-2016 EN event. These spatial patterns of warming and drought are compared with those observed in previous strong EN events (1982-1983 and 1997-1998) and other moderate to strong EN events (e.g. 2004-2005 and 2009-2010). The link between the spatial patterns of drought and sea surface temperature anomalies in the central and eastern Pacific is also explored. We show that indeed the EN2015-2016 led to unprecedented warming compared to the other EN events over Amazonia, Africa and Indonesia, as a consequence of the background global warming trend. Anomalous accumulated extreme drought area over Amazonia was found during EN2015-2016, but this value may be closer to extreme drought area extents in the other two EN events in 1982-1983 and 1997-1998. Over Africa, datasets disagree, and it is difficult to conclude which EN event led to the highest accumulated extreme drought area. Our results show that the highest values of accumulated drought area over Africa were obtained in 2015-2016 and 1997-1998, with a long-term drying trend not observed over the other tropical regions. Over Indonesia, all datasets suggest that EN 1982-1983 and EN 1997-1998 (or even the drought of 2005) led to a higher extreme drought area than EN2015-2016. Uncertainties in precipitation datasets hinder consistent estimates of drought severity over tropical regions, and improved reanalysis products and station records are required.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Record-breaking warming and extreme drought in the Amazon rainforest during the course of El Niño 2015-2016.

The El Niño-Southern Oscillation (ENSO) is the main driver of interannual climate extremes in Amazonia and other tropical regions. The current 2015/2016 EN event was expected to be as strong as the EN of the century in 1997/98, with extreme heat and drought over most of Amazonian rainforests. Here we show that this protracted EN event, combined with the regional warming trend, was associated with unprecedented warming and a larger extent of extreme drought in Amazonia compared to the earlier strong EN events in 1982/83 and 1997/98. Typical EN-like drought conditions were observed only in eastern Amazonia, whilst in western Amazonia there was an unusual wetting. We attribute this wet-dry dipole to the location of the maximum sea surface warming on the Central equatorial Pacific. The impacts of this climate extreme on the rainforest ecosystems remain to be documented and are likely to be different to previous strong EN events.

A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans.

Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download.

Comment on "Ecological importance of the thermal emissivity of avian eggshells".

Eggshell emissivity must be known to determine accurately the cooling rate of avian eggs when the parent, after heating by conduction during the incubation, is temporarily absent. We estimate possible values of eggshell emissivities from in-situ measurements and spectral libraries. Emissivity is near to 1 (probably higher than 0.95) and therefore its effect on cooling rate may be negligible, with differences between the temperature of the egg assuming a value of ε=0.95 and that of a blackbody (ε=1) below 0.2 °C.

Long-term prognostic value of endothelial dysfunction in patients with chest pain and angiographically normal coronary arteries.

OBJECTIVE: To evaluate the prognostic impact of endothelial function in patients with angina and angiographically normal coronary arteries. METHODS: In 147 consecutive patients with angina and normal coronary arteries on coronary angiography, we studied endothelial function by incremental intracoronary bolus of acetylcholine (ACh). Patients were divided in two groups according to their vasomotor response to ACh: 1) ACh+ group (n = 95), those with diffuse vasoconstriction during ACh administration; and 2) ACh- group (n = 52): those showing normal endothelial function. Cardiovascular events, including hospital admissions for unstable angina, myocardial infarction, coronary revascularization, stroke and cardiac death, were studied during a mean follow-up of 7 years. RESULTS: A total of 33 patients (22%) had cardiac events, 29 in the ACh+ group and 4 in the ACh- group (p = 0.002). ACh+ group patients had less time free of cardiovascular events (p = 0.001). Cox proportional regression analysis after controlling for conventional risk factors demonstrated that endothelial dysfunction was an independent predictor of cardiovascular events. If hospital admissions for unstable angina were excluded from the analysis, only 6 patients had major cardiac events, 5 patients in the ACh+ group vs. 1 patient in the ACh- group (p = 0.2). CONCLUSION: A simple endothelial function test performed in patients with angina and normal coronary angiograms may identify a subgroup of patients with high probability of cardiovascular events on long-term follow-up, mainly hospital readmissions for worsening angina.

Soil emissivity and reflectance spectra measurements.

We present an analysis of the laboratory reflectance and emissivity spectra of 11 soil samples collected on different field campaigns carried out over a diverse suite of test sites in Europe, North Africa, and South America from 2002 to 2008. Hemispherical reflectance spectra were measured from 2.0 to 14 microm with a Fourier transform infrared spectrometer, and x-ray diffraction analysis (XRD) was used to determine the mineralogical phases of the soil samples. Emissivity spectra were obtained from the hemispherical reflectance measurements using Kirchhoff's law and compared with in situ radiance measurements obtained with a CIMEL Electronique CE312-2 thermal radiometer and converted to emissivity using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) temperature and emissivity separation algorithm. The CIMEL has five narrow bands at approximately the same positions as the ASTER. Results show a root mean square error typically below 0.015 between laboratory emissivity measurements and emissivity measurements derived from the field radiometer.

[Enoxaparin vs. non-fractionated heparin in primary angioplasty of acute myocardial infarction]. / Eficacia y seguridad de la enoxaparina en la angioplastia primaria. Análisis comparativo con la heparina no fraccionada.

OBJECTIVE: The objective of this study is to compare the effectiveness of intravenous enoxaparin (ENX) and Non-fractionated Heparin (NFH) in primary angioplasty (PA) of acute myocardial infarction (PA-AMI). DESIGN: A prospective, observational study. PATIENTS AND METHODS: A total of 191 patients admitted at the hospital with the diagnosis of Acute Myocardial Infarction (AMI) and treated with primary angioplasty were included. ENX was used in 91 patients (47.6%) and NFH in 100 patients (52.4%). Choice of treatment was based on the operator's opinion. Patients with cardiogenic shock were excluded. The first group received an intravenous bolus of ENX (0.75-1 mg/Kg) and the second one NFH (70-100 u/Kg), depending on whether it was associated with abciximab or not. In-hospital follow-up was performed, evaluating mortality and bleeding complications of both treatments. RESULTS: In-hospital mortality was 1.1% for the ENX group and 3.3% for NFH one. No significant differences were found in the number of bleeding complications with ENX (4.4%) and NFH (9.0%). There was one subacute thrombosis of stent for the ENX group and 3 thrombosis in the NFH-treated group. No significant differences were found in size of infarction measure with troponin I level (63.1 for ENX and 54.8 for the NFH) or in the left ventricle ejection fraction on hospital discharge (51% for ENX and 49.4% for the NFH). CONCLUSIONS: Primary angioplasty can be safely sued with the intravenous administration of ENX, no significant differences being found between both treatments in mortality and bleeding complications.

Comparison Between Fractional Vegetation Cover Retrievals from Vegetation Indices and Spectral Mixture Analysis: Case Study of PROBA/CHRIS Data Over an Agricultural Area.

In this paper we compare two different methodologies for Fractional Vegetation Cover (FVC) retrieval from Compact High Resolution Imaging Spectrometer (CHRIS) data onboard the European Space Agency (ESA) Project for On-Board Autonomy (PROBA) platform. The first methodology is based on empirical approaches using Vegetation Indices (VIs), in particular the Normalized Difference Vegetation Index (NDVI) and the Variable Atmospherically Resistant Index (VARI). The second methodology is based on the Spectral Mixture Analysis (SMA) technique, in which a Linear Spectral Unmixing model has been considered in order to retrieve the abundance of the different constituent materials within pixel elements, called Endmembers (EMs). These EMs were extracted from the image using three different methods: i) manual extraction using a land cover map, ii) Pixel Purity Index (PPI) and iii) Automated Morphological Endmember Extraction (AMEE). The different methodologies for FVC retrieval were applied to one PROBA/CHRIS image acquired over an agricultural area in Spain, and they were calibrated and tested against in situ measurements of FVC estimated with hemispherical photographs. The results obtained from VIs show that VARI correlates better with FVC than NDVI does, with standard errors of estimation of less than 8% in the case of VARI and less than 13% in the case of NDVI when calibrated using the in situ measurements. The results obtained from the SMA-LSU technique show Root Mean Square Errors (RMSE) below 12% when EMs are extracted from the AMEE method and around 9% when extracted from the PPI method. A RMSE value below 9% was obtained for manual extraction of EMs using a land cover use map.

The inferior radiolucent area within the cardiac silhouette: validation as a landmark for coronary sinus catheterization.

BACKGROUND: Catheterization of the coronary sinus (CS) plays a preponderant role in device implantation and electrophysiology. Nevertheless, catheterization of this structure can be time-consuming and is related to operator experience. An inferior radiolucent area of the cardiac right anterior oblique (RAO) view has been suggested as a landmark to guide CS catheterization. However, the true relationship of this area with the CS ostium (CSO) has not been studied. METHODS: Thirty-five consecutive patients who underwent right coronary angiography were prospectively enrolled in the study. Fluoroscopic images of the heart in the right anterior oblique, both immediately before and during the venous phase of right coronary angiography, were recorded and digitally stored. Postprocedure measurements of the inferior radiolucent area within the cardiac silhouette and, subsequently, the distance of this area to the CSO, were performed by two independent observers. RESULTS: A radiolucent area of 9.5 +/- 3.0 x 11.0 +/- 3.4 mm was identified in the inferior annulus by the two evaluators in all patients. No significant differences in the dimensions of this area were found between the two observers. The CSO was 9.6 +/- 7.2 mm superior and 0.1 +/- 9.0 mm posterior to the radiolucent area and no statistically significant differences were found between the two observers. CONCLUSION: An inferior radiolucent area can be identified within the cardiac silhouette in most patients in the RAO view. This area is slightly anterior and inferior to the CSO and can be used for catheterization guidance of this latter structure.

[Post-infarction ventricular tachycardia with a QRS complex narrower than 140 ms: characterization and catheter ablation]. / Taquicardia ventricular postinfarto de QRS inferior a 140 ms: caracterización y ablación con catéter.

Typically, sustained monomorphic ventricular tachycardia (SMVT) in patients with a previous myocardial infarction (MI) is characterized by a wide QRS complex. However, occasionally patients present with SMVT and a narrow QRS complex (N-SMVT). We studied retrospectively the incidence of N-SMVT (i.e., QRS interval <140 ms) in patients with a previous MI and inducible SMVT who underwent electrophysiological evaluation. Of the 135 consecutive patients with inducible SMVT, 8 (5.9%) presented with inducible N-SMVT. The mean QRS complex duration in patients with N-SMVT was 126 (8) ms. Radiofrequency ablation was successful in 5 out of 6 patients (83%). One of the remaining two received an implantable defibrillator, while the other was given amiodarone. Findings during radiofrequency ablation showed that the reentry circuit was located in the left septum in 4 out of the 5 patients (80%). N-SMVT is relatively uncommon, but the success rate of radiofrequency ablation is high. The reentry circuit is most often located in the septum.

[Secondary prevention program: impact on cardiovascular risk]. / Programa de prevención secundaria: influencia sobre el riesgo cardiovascular.

The aims of this study were to determine the effect of a secondary prevention program on the treatment and control of coronary risk factors and to assess whether it improves functional capacity. The study involved 401 patients with coronary heart disease (mean age 57.1 years; 89% men). Clinical and anthropometric data, including blood pressure, were recorded, and electrocardiography, laboratory analysis and exercise testing were performed before and after the program, which lasted 2-3 months. The therapeutic intervention comprised pharmacological treatment of coronary risk factors and the encouragement of life-style changes, including a recommended medically supervised physical exercise regime. By the end of the program, lipid and lipoprotein levels had improved significantly (P< .001 for all). The proportion of smokers decreased from 37.4% to 3.6% (P< .001). Functional capacity increased by 26% (P< .001). In conclusion, patients who took part in the secondary prevention program experienced improvements in cardiovascular risk profile and functional capacity.

Emissitivity spectra obtained from field and laboratory measurements using the temperature and emissivity separation algorithm.

Surface emissivities play an important role in thermal remote sensing, since knowledge of them is required to estimate land surface temperature with enough accuracy. They are also important in other environmental or geological studies. We show the results obtained for the emissivity spectra of different natural surfaces (water, green, and senescent vegetation) by applying the temperature and emissivity separation (TES) algorithm to ground-based measurements collected at the field with a multiband thermal radiometer. The results have been tested with data included in spectral libraries, and rms errors lower than 0.01 have been found, except for senescent vegetation. Two methods are also proposed to apply the TES algorithm to measurements achieved in the laboratory: (i) by heating the sample and (ii) using a box with reflective walls.

Syncope following cardioverter defibrillator implantation in patients with spontaneous syncopal monomorphic ventricular tachycardia.

AIMS: We sought to determine the incidence, mechanisms, and time to syncope recurrence in patients with spontaneous syncopal monomorphic ventricular tachycardia (SyMVT) treated with an implantable cardiac defibrillator (ICD). METHODS AND RESULTS: Incidence and causes of syncope following ICD implantation in consecutive patients (n=26) with spontaneous SyMVT were compared with those found in consecutive patients (n=50) with spontaneous non-syncopal monomorphic ventricular tachycardia (NSyMVT). Patients with SyMVT had a higher incidence of syncope (46% patients) than those with NSyMVT (2% patients) at 31+/-21 and 34+/-23 months follow-up, respectively (hazard ratio, 0.19; 95% confidence interval, 0.04-0.42; P=0.0001). Among the former, four patients (15%) had non-arrhythmic syncope and eight patients had arrhythmic syncope (31%), which was associated with either ICD proarrhythmia (seven episodes of VT acceleration or VF degeneration by ATP or low/high-energy shocks in three patients) or spontaneous VT and VF (five episodes in five patients). Median time to the first arrhythmic syncope was 376 days. Arrhythmic syncope presented after a first non-syncopal VT recurrence in six patients (75%). CONCLUSION: Syncope following ICD implantation is common in patients with SyMVT in contrast to patients with NSyMVT. Late syncope presentation supports reassessment of driving restrictions in this setting.

Superior vena cava flutter: electrophysiology and ablation.

INTRODUCTION: Reentry within a major thoracic vein has been suggested as a cause of atrial arrhythmias. However, little is known about these potential reentrant circuits. METHODS AND RESULTS: Atypical atrial flutter was induced and mapped in 67 out of 225 atrial flutter ablation procedures. Reentry around the superior vena cava (SVC) was suspected in three patients. The suspected SVC flutter was induced and terminated by pacing in all patients. Fusion was demonstrated during flutter entrainment by subeustachian isthmus pacing in all of them. The postpacing interval following entrainment by pacing from different sites of the right atrium (RA) or coronary sinus was longer than the flutter cycle length. Macroreentry within the SVC was demonstrated both by sequential activation and a postpacing interval matching the flutter cycle length when pacing from different sites around the SVC in all patients. Atrial-venous-atrial electrogram sequence was demonstrated following flutter entrainment by atrial pacing. Flutter was terminated by an electrical stimulus delivered to the SVC, which was not propagated to the trabeculated RA, in one patient, and linear radiofrequency application from the distal SVC to the posterior wall of the RA, or to the superoseptal portion of the crista terminalis, in the other two. CONCLUSION: Macroreentry within the SVC is a distinctive mechanism responsible for rapid atrial activation, which is different from other reported flutter mechanisms, such as upper loop reentry. SVC longitudinal radiofrequency application can eliminate the arrhythmia without the need for complete electrical disconnection of the vein.

[Budd-Chiari syndrome with complete occlusion of the inferior vena cava: percutaneous recanalization by angioplasty and stenting]. / Síndrome de Budd-Chiari por obstrucción completa de la vena cava inferior: recanalización percutánea mediante angioplastia e implante de stent.

A 47-year-old man was diagnosed with primary antiphospholipid syndrome and Budd-Chiari syndrome (membranous complete obstruction of the intrahepatic inferior vena cava), with edema and ascites refractory to medical treatment. The inferior vena cava membrane was punctured with a Brockenbrough needle under multidirectional fluoroscopic guidance via a transfemoral approach. The occlusion was dilated with balloons of increasing size and was subsequently stented successfully. At 1-year follow-up venography showed patency of the stent, and the patient remains asymptomatic 2 years after the procedure.

Experimental measurements for studying angular and spectral variation of thermal infrared emissivity.

One condition for precise multiangle algorithms for estimating sea and land surface temperature with the data from the Advanced Along Track Scanning Radiometer is accurate knowledge of the angular variation of surface emissivity in the thermal IR spectrum region. Today there are very few measurements of this variation. The present study is conducted to provide angular emissivity measurements for five representative samples (water, clay, sand, loam, gravel). The measurements are made in one thermal IR broadband (8-13 microm) and three narrower bands (8.2-9.2, 10.3-11.3, and 11.5-12.5 microm) at angles of 0 degrees-60 degrees (at 5 degrees increments) to the surface normal. The results show a general decrease in emissivity with increasing viewing angles, with the 8.2-9.2-microm channel the most sensitive to this dependence and sand the sample showing the greatest variation.