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In comets and in the cold phase of the interstellar medium (ISM), ammonium salts are key molecular species due to their role in the retention of volatile compounds on cold surfaces. In the case of sulphur, the H |$_2$| S/OCS ratio observed in protostars could be explained by the presence of ammonium hydrosulphide (NH |$_4$| SH) salts. However, laboratory data on the properties of NH4SH in ISM cold relevant conditions are rather scarce, as they usually focus on the atmosphere of Jupiter. We propose to consolidate the laboratory data regarding NH |$_4$| SH on grains, by performing temperature programmed desorption experiments and Fourier transform infrared reflection spectroscopy. The salt was also exposed to H atoms to mimic the ISM conditions. NH |$_4$| SH was found to form in situ at 10 K, from a mixture of ammonia (NH |$_3$|⁠) and hydrogen sulphide (H |$_2$| S). The NH |$_4^+$| infrared feature (1485 cm |$^{-1}$|⁠) is the most prominent one at 80 K. As pure species, H |$_2$| S and NH |$_3$| desorb at 76 and 90 K, respectively, whereas they are released into the gas phase at 153 K when adsorbed in the form of salt. The presence of water delays the desorption of the salt until the very end of the water desorption, but does not affect the desorption kinetics. During H-exposure, the salt is dissociated and no new product was detected. As a comparative study, salts have been included in the Nautilus gas–grain model. The results show a good correlation with the observations of IRAS 16293−2422B, as opposed to when NH |$_4$| SH is not included in the model. [ABSTRACT FROM AUTHOR]

Context. Nitrogen-bearing molecules (such as N2H+ and NH3) are excellent tracers of high-density and low-temperature regions, such as dense cloud cores. Notably, they could help advance the understanding of snow lines in protoplanetary discs and the chemical evolution of comets. However, much remains unknown about the chemistry of N-bearing molecules on grain surfaces, which could play an important role in their formation and evolution. Aims. In this work, we experimentally study the behaviour of NH3 on surfaces that mimic grain surfaces under interstellar conditions in the presence of some other major components of interstellar ices (i.e. H2O, CO2, CO). We measure the binding energy distributions of NH3 from different H2O ice substrates and also investigate how it could affect the NH3 snow line in protoplanetary discs. Methods. We performed laboratory experiments using the ultra-high vacuum (UHV) set-up VENUS (VErs des NoUvelles Syntheses). We co-deposited NH3 along with other adsorbates (H2O, 13CO, and CO2) and performed temperature programmed desorption (TPD) and temperature programmed-during exposure desorption (TP-DED) experiments. The experiments were monitored using a quadrupole mass spectrometer and a Fourier transform reflection absorption infrared spectrometer (FT-RAIRS). We obtained the binding energy distribution of NH3 on crystalline ice (CI) and compact amorphous solid water ice by analysing the TPD profiles of NH3 obtained after depositions on these substrates. Results. In the co-deposition experiments, we observed a significant delay in the desorption and a decrease of the desorption rate of NH3 when H2O is introduced into the co-deposited mixture of NH3–13CO or NH3–CO2, which is not the case in the absence of H2O. Secondly, we noticed that H2O traps roughly 5–9% of the co-deposited NH3, which is released during the phase change of water from amorphous to crystalline. Thirdly, we obtained a distribution of binding energy values of NH3 on both ice substrates instead of an individual value, as assumed in previous works. For CI, we obtained an energy distribution between 3780 K and 4080 K, and in the case of amorphous ice, the binding energy values were distributed between 3630 K and 5280 K; in both cases we used a pre-exponential factor of A = 1.94 × 1015 s−1. Conclusions. From our experiments, we conclude that the behaviour of NH3 is significantly influenced by the presence of water, owing to the formation of hydrogen bonds with water, in line with quantum calculations. This interaction, in turn, preserves NH3 on the grain surfaces longer and up to higher temperatures, making it available closer to the central protostar in protoplanetary discs than previously thought. It explains well why the NH3 freeze-out in pre-stellar cores is efficient. When present along with H2O, CO2 also appears to impact the behaviour of NH3, retaining it at temperatures similar to those of water. This may impact the overall composition of comets, particularly the desorption of molecules from their surface as they approach the Sun. [ABSTRACT FROM AUTHOR]

A gestão de territórios fronteiriços é um desafio para os governos subnacionais por conta da descontinuidade territorial. As zonas de fronteiras são formadas por, pelo menos, duas áreas geográficas pertencentes a países distintos. Muitos dos problemas e dificuldades da gestão são compartilhados pelos vizinhos, mas não suas soluções, que esbarram nos limites jurisdicionais. Cada vez mais são observadas as necessidades de municípios fronteiriços serem protagonistas no enfrentamento de dificuldades que excedem seus limites geográficos. Este artigo discute as possibilidades de governança territorial entre territórios localizados em regiões de fronteira. Para tanto, recorreu-se a pesquisa bibliográfica e vivências em consulados brasileiros no exterior de um dos autores. Constatou-se já existir uma literatura que acena para a importância da participação dos governos subnacionais nos rumos da política internacional, em especial. Os municípios fronteiriços podem e devem estimular iniciativas de cooperação e aproveitar instrumentos já existentes, como os comitês de fronteira, para que se tornem porta-vozes dos clamores locais juntos aos governos nacionais.

Accurate and early yield estimation (from pea size) allows 1.- Make decisions at field level: green harvesting, irrigation management. 2.- Advance or organise the purchase of grapes from suppliers. 3.- Forecast the volume of wine produced in the campaign that has not yet begun. 4.- Define the quality of the vintage: regular and detailed monitoring of whether, or not, the heterogeneity of the leaf surface, photosynthetic activity or soil moisture observed in the vineyards is as expected at this time, compared with historical values. 5.- Precise control of each vine in production, knowing which vines are no longer productive or should be grubbed up. The Sentinel-2 satellite has generated a time series of images spanning more than six years, which is a great help in analysing the state of permanent crops such as vineyards, where grapes are produced every year. The weekly comparison of what is happening in the current season with what has happened in the previous six seasons is information that is in line with agricultural practices: Winegrowers make the mental exercise of comparing how the vines are developing today with how they developed in previous seasons, with the aim of repeating the years of good yields. In addition, several commercial satellites can now capture images of 50 centimetres pixel resolution or even better, making it possible to check the health of each vine every year. Since 2020, GMV and Pago de Carraovejas have been working together to develop a yield estimation service based on field information and satellite images that feed machine learning algorithms. This paper describes the path followed from the beginning and the steps taken, summarising as follows: 1. - Machine learning algorithm trained with cluster counting and satellite data. 2. - Adjustment of the number of vines in production in each vineyard using very high-resolution imagery. 3. - Machine learning algorithm trained on real production from past campaigns and historical Sentinel-2 time series. The results obtained by comparing the actual grape intake in the winery with the yield estimation range from 91% accuracy in 2020 to 95% accuracy in 2022.