Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission

Biomass is a spaceborn polarimetric P-band (435 MHz) synthetic aperture radar (SAR) in a dawn-dusk low Earth orbit. Its principal objective is to measure biomass content and change in all the Earth’s forests. The ionosphere introduces Faraday rotation on every pulse emitted by low-frequency SAR and scintillations when the pulse traverses a region of plasma irregularities, consequently impacting the quality of the imaging. Some of these effects are due to Total Electron Content (TEC) and its gradients along the propagation path. Therefore, an accurate assessment of the ionospheric morphology and dynamics is necessary to properly understand the impact on image quality, especially in the equatorial and tropical regions. To this scope, we have conducted an in-depth investigation of the significant noise budget introduced by the two crests of the Equatorial Ionospheric Anomaly (EIA) over Brazil and South-East Asia. The work is characterized by a novel approach to conceive a SAR-oriented ionospheric assessment, aimed at detecting and identifying spatial and temporal TEC gradients, including scintillation effects and Traveling Ionospheric Disturbances, by means of Global Navigation Satellite Systems (GNSS) ground-based monitoring stations. The novelty of this approach resides in the customization of the information about the impact of the ionosphere on SAR imaging as derived by local dense networks of ground instruments operating during the passes of Biomass spacecraft. The results identify the EIA crests as the regions hosting the bulk of irregularities potentially causing degradation on SAR imaging. Interesting insights about the local characteristics of low-latitudes ionosphere are also highlighted

Implications of the presence of yeasts in tracheobronchial secretions of critically ill intubated patients

The presence of some microorganisms in the respiratory tract is a known risk factor for the infection of air passages; however, it is not clear whether this holds true for Candida spp. Thus, our objective was to determine the frequency of yeast colonization in the tracheobronchial secretions of critically ill intubated patients and to assess the presence of these yeasts in the infra-cuff region of the endotracheal tube (ET). Patients aged 18 years or older who had been using an endotracheal tube for 48 hours were recruited. Tracheal secretions were collected; after extubation, the ETs were cut into two fragments in the infra-cuff region. One of these fragments was placed in a solution containing antibiotics and sent to the lab for cultu re and identification of yeasts. The remaining fragment was fixed and subjected to scanning electron microscopy (SEM). In total, 20 patients with an average age of 73.3 years (± 13.1) participated in this study. These patients remained under endotracheal intubation and invasive mechanical ventilation for an average of 6. 4 (± 1.8) and 13.5 days (± 15), respectively. Of these patients, 45 % showed respiratory tract colonization by yeasts of the Candida genus, with C. albicans being the most frequently isolated species (66.7 %). Moreover, in almost 90 % of these patients, blastoconidia of the same yeast were found in the infra-cuff portion of the ET, as evidenced by SEM, strongly fixed on the ET surface. Yeasts isolated from both the infra-cuff region and the tracheobronchial secretions were susceptible to amphotericin B and fluconazole. In conclusion, our results show that the frequency of colonization by yeasts of the Candida genus in the tracheobronchial secretions of intubated patients within 48 hours is high, and that these species can also be found as a biofilm on the ET surface

Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission

Biomass is a spaceborn polarimetric P-band (435 MHz) synthetic aperture radar (SAR) in a dawn-dusk low Earth orbit. Its principal objective is to measure biomass content and change in all the Earth's forests. The ionosphere introduces the Faraday rotation on every pulse emitted by low-frequency SAR and scintillations when the pulse traverses a region of plasma irregularities, consequently impacting the quality of the imaging. Some of these effects are due to total electron content (TEC) and its gradients along the propagation path. Therefore, an accurate assessment of the ionospheric morphology and dynamics is necessary to properly understand the impact on image quality, especially in the equatorial and tropical regions. To this scope, we have conducted an in-depth investigation of the significant noise budget introduced by the two crests of the equatorial ionospheric anomaly (EIA) over Brazil and Southeast Asia. This paper is characterized by a novel approach to conceive a SAR-oriented ionospheric assessment, aimed at detecting and identifying spatial and temporal TEC gradients, including scintillation effects and traveling ionospheric disturbances, by means of Global Navigation Satellite Systems ground-based monitoring stations. The novelty of this approach resides in the customization of the information about the impact of the ionosphere on SAR imaging as derived by local dense networks of ground instruments operating during the passes of Biomass spacecraft. The results identify the EIA crests as the regions hosting the bulk of irregularities potentially causing degradation on SAR imaging. Interesting insights about the local characteristics of low-latitudes ionosphere are also highlighted.</p