Search

The objective of this paper is to carry out a systematic investigation about the sensitivity of radar to maize crop growth and soil moisture by considering a wide range of frequencies and angles and all linear polarizations. We show the results of a correlation study carried out on the data collected on a maize field at Suberg, in the Swiss region named Central Plain, by the multifrequency RAdio ScAtteroMeter (RASAM). This agricultural field was monitored over a long period of time at a wide range of frequencies and observation angles so that the correlation between the backscattering and crop height and the biomass and soil moisture was studied under several plant and observation conditions. Moreover, we describe some recent refinements applied to the vegetation scattering model developed at Tor Vergata University, Rome, Italy, and we evaluate the accuracy of extended comparisons between model outputs and RASAM signatures. The Tor Vergata model is finally applied to give a theoretical basis to the experimental correlation findings. Index Terms--Biomass, crops, modeling, radar, soil moisture.

Objectives: Scarce data are currently available on the kinetics of antibodies after vaccination with mRNA vaccines as a whole and, with mRNA-1273, in particular. We report here an ad-interim analysis of data obtained after a 6-month follow-up in a cohort of healthcare workers (HCWs) who received the mRNA-1273 vaccine. These new data provide more insight into whether and in whom a 3rd dose could be necessary.Methods: Our study compared the anti-S antibody kinetics at 2 weeks (T1), 3 months (T3) and 6 months (T4) after the first injection, and 2 weeks after the second injection (T2). The 201 participating HCWs were stratified according to their initial serological status. The vaccine effectiveness was also assessed through a medical questionnaire.Results: We report here a marked and statistically significant antibody decrease (P < 0.05) between T3 and T4, especially in naïve vaccinees. The analysis of potential confounding factors or known risk factors for severe COVID-19 disease did not reveal any influence on the drop observed. Six-month after vaccination, only one, symptomatic, infection was reported in our cohort.Conclusions: In a supply-limited environment, our results plead for reserving the 3rd dose scheme, in the upcoming months, to seronegative individuals prior to vaccination, especially when the serological status is easily accessible. [ABSTRACT FROM AUTHOR]

• A single dose of mRNA-1273 appears to be sufficient in the vast majority of seropositive individuals prior to vaccination. • Previously infected workers experienced more frequent and severe common side effects after the first dose. • The second dose induced greater overall reaction than the first one regardless of the serological status. [ABSTRACT FROM AUTHOR]

Background: Hepatitis E virus (HEV) is widely distributed worldwide and is endemic in developing countries. Travel-related HEV infection has been reported at national levels, but global data are missing. Moreover, the global availability of HEV diagnostic testing has not been explored so far. The aim of this study is to describe the epidemiology of HEV infections in returning travellers and availability of HEV diagnostic testing in the GeoSentinel surveillance network.Methods: This was a multicentre retrospective cross-sectional study. All confirmed and probable HEV travel-related infections reported in the GeoSentinel Network between 1999 and 2018 were evaluated. GeoSentinel sites were asked to complete a survey in 2018 to assess the availability and accessibility of HEV diagnostic procedures (i.e. serology and molecular tests) throughout the study period.Results: Overall, 165 travel-related HEV infections were reported, mainly since 2010 (60%) and in tourists (50%). Travellers were exposed to hepatitis E in 27 countries; most travellers (62%) were exposed to HEV in South Asia. One patient was pregnant at the time of HEV infection and 14 had a concomitant gastrointestinal infection. No deaths were reported. In the 51% of patients with information available, there was no pre-travel consultation. Among 44 GeoSentinel sites that responded to the survey, 73% have access to HEV serology at a local level, while 55% could perform (at a local or central level) molecular diagnostics.Conclusion: Reported access to HEV diagnostic testing is suboptimal among sites that responded to the survey; this could negatively affect diagnosing HEV. Pre-travel consultations before travel to South Asia and other low-income and high-prevalence areas with a focus on food and water precautions could be helpful in preventing hepatitis E infection. Improved HEV diagnostic capacity should be implemented to prevent and correctly diagnose travel-related HEV infection. [ABSTRACT FROM AUTHOR]

As an extension of the PROBA-Vegetation (PROBA-V) user segment, the European Space Agency (ESA), de Vlaamse Instelling voor Technologisch Onderzoek (VITO), and partners TRASYS and Spacebel developed an operational Mission Exploitation Platform (MEP) to drastically improve the exploitation of the PROBA-V Earth Observation (EO) data archive, the archive from the historical SPOT-VEGETATION mission, and derived products by researchers, service providers, and thematic users. The analysis of the time series of data (petabyte range) is addressed, as well as the large scale on-demand processing of the complete archive, including near real-time data. The platform consists of a private cloud environment, a Hadoop-based processing environment and a data manager. Several applications are released to the users, e.g., a full resolution viewing service, a time series viewer, pre-defined on-demand processing chains, and virtual machines with powerful tools and access to the data. After an initial release in January 2016 a research platform was deployed gradually, allowing users to design, debug, and test applications on the platform. From the PROBA-V MEP, access to, e.g., Sentinel-2 and Sentinel-3 data will be addressed as well. [ABSTRACT FROM AUTHOR]

This paper shows a model study about the emissivity of forests. Model outputs are compared with multifrequency airborne measurements carried out over five broadleaf forests in Italy. Two flights took place, in summer 1999 and winter 2002. Available ground truth included important variables, such as biomass, tree density, and average trunk diameter. This data set, in conjunction with allometric equations and information taken from the literature, is used to give inputs to the model. A general agreement between simulated and measured data is observed L-, C-, and X-bands. The same model is used to investigate the sensitivity of forest emissivity to soil moisture, woody volume, and average diameter. As expected, a moderate effect of soil moisture is observed only at L-band and for forests with a lower woody volume. At L-band, the model predicts a general increase emissivity with woody volume but indicates that also the trunk diameter exerts an important influence, since it is a variable which controls several geometrical properties. These results allow us to single out the influence of soil moisture, woody volume, and geometrical properties at L-band. The increase of emissivity with frequency, observed in experimental data, is interpreted by means of electromagnetic considerations about branch scattering. [ABSTRACT FROM AUTHOR]