Institut UTINAM

Abstract Rain‐on‐snow (ROS) events in the Arctic can lead to major impacts on the snow cover, cryosphere and environment. During the last decades, these events have significantly increased, mostly due to climate change. Here, we use outputs from the regional climate model MAR (version 3.14) driven by the ERA5 reanalysis at 10‐km resolution over Greenland, in the period 1940–2023. MAR is used to simulate the climatological properties of summertime ROS events over Greenland, and their long‐term changes over the period. The analyses also focused on the years after 1979, when reanalyses are more reliable. We found that both the spatial extension, the frequency, and rainfall amounts associated with ROS events all strongly increased, especially along the West and East coasts of Greenland. These changes either appeared, or strongly accelerated, during the last 40 yrs. We also analyzed the synoptic configurations conducive to major ROS events (the top 10% in terms of size and amounts). Poleward advection of moisture and heat generally prevails but shows non‐negligible variability in their location, direction and strength of associated centers of action. About 10%–20% of those major ROS events correspond to atmospheric rivers, events that occur 1%–2% of the time but increase the probability of rainfall over Greenland by a factor 10 to nearly 40 locally, with respect to the climatology.

Study presents a comparative analytical investigation into the green synthesis of monometallic and bimetallic nanoparticles using Punica granatum (pomegranate) extract, aimed at developing high-performance electrochemical sensors for the detection of ciprofloxacin (CIP) as a representative pharmaceutical pollutant. Three nanoparticle systems were successfully synthesized: monometallic Au@NPs and TiO2@NPs, as well as the bimetallic AuTiO2@NPs. Their structural and physicochemical characteristics were comprehensively analyzed using UV–Vis spectroscopy, FTIR, SEM, TEM, and XRD techniques. The obtained nanoparticles exhibited predominantly spherical morphologies with average particle sizes of approximately 40 ± 5 nm for Au@NPs, 50 ± 7 nm for TiO2@NPs, and 60 ± 6 nm for AuTiO2@NPs. These nanomaterials were subsequently employed to modify electrode surfaces for electrochemical sensing applications. Their analytical performance was evaluated using cyclic voltammetry (CV) and square-wave voltammetry (SWV). The sensors displayed excellent sensitivity, with limits of detection of 0.8 ppb for TiO2@NPs, 0.8 ppb for Au@NPs, and 0.2 ppb for the AuTiO2@NP-based sensor. The bimetallic platform demonstrated superior electrochemical behavior, enhanced signal intensity, and strong selectivity, achieving recovery rates of 98% in tap water and 103% in wastewater. Overall, the results confirm the effectiveness of green-synthesized bimetallic nanoparticles as efficient, low-cost materials for environmental monitoring of emerging pharmaceutical contaminants.

The $\mathbf{C O}_{\mathbf{2}}$ molecule, a greenhouse gas, is characterized by three vibrational modes: $i) v_{1}$, a symmetric stretching vibration, ii) $v_{2}$, a double degenerate symmetric bending mode and iii) $v_{3}$, an anti-symmetric stretching vibration, with absorption frequencies in the mid infrared range. In a recent publication, it was shown that at the harmonic level, the CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> molecule preserves its vibrational symmetry when trapped in nanocages of Clathrate or rare gas matrices with a degeneracy lifting of the bending mode. The symmetry of the molecule is preserved even for the fermi levels that originate from the interaction between fundamental $v_{1}$ and $2 v_{2}$ states when their frequency values coincide. This work, is an attempt to analyze the vibrational degrees of freedom of $\mathbf{C O}_{\mathbf{2}}$ from a numerical algorithm based on a neural network algorithm used as a tool to sample the electronic environment from the vibrational motion of the nuclei clamped to form the molecule either when it moves freely as in gas phase or under an electro-magnetic constraint when trapped in a nanocage. To achieve this goal, the molecule is characterized by its force constant as determined in the previous work rather than by its harmonic vibrational frequencies. Different recognition strategies will be shown through the application of standard neural network with back-propagation algorithm.

Several fruits and vegetables deteriorate within a few days, which poses a major challenge for their preservation and commercialization. To address this issue, this study reports on developing eco-friendly and safe films based on pectin extracted from lemon peel, enriched with essential oils, for a sustainable preservation of tomatoes. Pectin was extracted from Citrus limon peels using an innovative high-pressure treatment, achieving higher yields than conventional methods. The extracted pectin was characterized using advanced analytical techniques, FT-IR, Nuclear Magnetic Resonance (NMR), Size Exclusion Chromatography (SEC), and Gas Chromatography-Mass Spectrometry (GC-MS). Additionally, essential oils extracted from lemon and laurel were characterized by GC-MS to identify their active components. Pectin-chitosan-based films, with or without laurel and lemon essential oils, were prepared and evaluated for their mechanical properties, antimicrobial activity, moisture resistance, solubility, and biodegradability. These films were then tested for tomato preservation, demonstrating a significant extension of their shelf life beyond one month. Acting as a protective second skin, these films extend the freshness of fruits and vegetables by preventing microbial growth and reducing moisture loss. The results highlight the potential of these safe and eco-friendly films as a promising alternative to conventional plastic films. • Pectin was extracted from lemon peels ( Citrus limon ) using a high-pressure treatment. • Pectin-chitosan films were loaded with laurel and lemon essential oils. • The films demonstrated strong antibacterial activity against common bacteria. • The films are promising candidates for sustainable food packaging. • The films present active preservation properties.

In human geography, observed centralities consist of more or less significant concentrations of people, activities, buildings or network nodes, which vary across space and evolve over time. Due to their spatial materiality, human settlements are relatively enduring over the span of a year, several years or even longer. This chapter presents the essential determinants of the existence of centralities, whether more permanent or occasional, in the geographic systems describing the functioning of societies in space. The concentrations and dispersions studied in human geography are the result of the functioning of societies in space, which is why the social and the spatial are fundamentally linked in the study of centralities. Social determinism asserts the primacy of society over the individual; the actions of society and its main institutions determine individual behaviors and, consequently, the resulting spatial configurations. Cities represent especially prominent forms of concentration on a global scale and are remarkably enduring over time.

Young massive clumps are relatively rare objects and are typically found at large distances. The G202.02+2.85 (hereafter, G202) massive clump was identified in the Monoceros OB 1 molecular complex at a distance of about 700 pc. It was found to be undergoing active star formation and located at the junction point between two colliding filaments. We aim to further clarify the evolutionary stage of the clump and the nature of the collision and of six dense cores in the area; specifically, we investigate whether the clump is collapsing as a whole and/or whether it shows signs of shocks. To this end, we examined the dense gas properties, notably through NH_3 and mathrm N_ H^ and their deuterated counterparts. We examined the evolutionary stages of the cores through deuterium fractionation values. We performed a mapping of the clump and deeper pointed molecular line observations towards the dense cores with the IRAM 30-m and Effelsberg 100-m telescopes in the 3-mm and centimetre ranges, respectively. The clump internal dynamics was examined using tracers of various gas densities (CO isotopologues, CS, ammonia, and diazenylium), along with a classical infall diagnosis with HCO^+ and diazenylium. Furthermore, SiO and methanol were used to characterise the shock properties. The evolutionary stages of the dense cores were evaluated from the deuterium fractionation of ammonia and diazenylium. The clump seen in dust continuum emission was detected in all dense-gas molecular tracers, including deuterated ammonia and diazenylium, contrasting with the distributions in shock tracers SiO and CH_3OH. These latter include both features compatible with protostellar outflows and a more diffuse emission in the clump, all with SiO line width corresponding to relatively low velocity shocks (lesssim 10 ). This could arise from multiple, blended outflows or be a signature of the filament collision. All the dense cores, except for the source 1446, were found to be in early evolutionary stages, the most massive one, the source 1450, being at most a Class 0 object. This is consistent with the idea that they originate in the same clump-compression event. They all present virial parameters indicating gravitational instability, while source 1450 and its surroundings show blue-shift asymmetry in HCO^+ compatible with gravitational infall, suggesting that this star formation activity came out of the collision. We find that, in contrast to NH_3 deuterium fractionation, the N_2H^+ deuterium fractionation values are likely to be correlated with the source evolutionary stage. Our results provide additional evidence that the star-forming cores in the G202 clump originate in the clump compression due to filament collision or convergence. Based on its physical parameters, we find that the source 1454 in the northern clump of G202 may represent the physical state of the region before the collision of the two filaments that make up the junction region. Determining the origin of the collision will require the examination of the large-scale motion of the gas.

We present 850 μm thermal dust polarization observations with a resolution of 14.″4 (∼0.13 pc) toward an infrared dark cloud G16.96+0.27 using James Clerk Maxwell Telescope/POL-2. The average magnetic field orientation, which roughly agrees with the larger-scale magnetic field orientation traced by the Planck 353 GHz data, is approximately perpendicular to the filament structure. The estimated plane-of-sky magnetic field strength is ∼96 μG and ∼60 μG using two variants of the Davis–Chandrasekhar–Fermi methods. We calculate the virial and magnetic critical parameters to evaluate the relative importance of gravity, the magnetic field, and turbulence. The magnetic field and turbulence are both weaker than gravity, but magnetic fields and turbulence together are equal to gravity, suggesting that G16.96+0.27 is in a quasi-equilibrium state. The alignment between the magnetic field and cloud is found to have a trend moving away from perpendicularity in the dense regions, which may serve as a tracer of potential fragmentation in such quiescent filaments.