Chemicals of Emerging Arctic Concern in north-western Spitsbergen snow: Distribution and sources

Personal care products contain chemicals that are considered of emerging concern in the Arctic. In this study, a selected group of personal care products was investigated in the snowpack on north-western Spitsbergen. We report a preliminary study on the spatial and seasonal distribution of 13 ingredients commonly found in personal care products, including fragrance materials, UV filters, BHT and BPA. Possible sources and deposition processes are discussed. Experimental analyses utilizing GC–MS/MS, were complemented with outputs from the HYSPLIT transport and dispersion model. The results reveal the presence of all selected compounds in the snow, both in proximity to and distant from the research village of Ny-Ålesund. For some of these chemicals this is the first time their presence is reported in snow in Svalbard. These chemicals show different partitioning behaviours between the particulate and dissolved phases, affecting their transport and deposition processes. Additionally, concentrations of certain compounds vary across different altitudes. It is observed the relevance of long-range atmospheric transport during winter at most sites, and, regardless of the proximity to human settlements, snow concentrations can be influenced by long-distance sources. This study highlights the need for detailed information on CEACs' physical-chemical properties, considering their potential impact on fresh and marine waters during the snowmelt under climate change

Excess decay for minimizing hypercurrents mod 2Q2Q

We consider codimension $1$ area-minimizing $m$-dimensional currents $T$ mod an even integer $p=2Q$ in a $C^2$ Riemannian submanifold $\Sigma$ of the Euclidean space. We prove a suitable excess-decay estimate towards the unique tangent cone at every point $q\in \mathrm{spt} (T)\setminus \mathrm{spt}^p (\partial T)$ where at least one such tangent cone is $Q$ copies of a single plane. While an analogous decay statement was proved in arXiv:2111.11202 as a corollary of a more general theory for stable varifolds, in our statement we strive for the optimal dependence of the estimates upon the second fundamental form of $\Sigma$. This technical improvement is in fact needed in arXiv:2201.10204 to prove that the singular set of $T$ can be decomposed into a $C^{1,\alpha}$ $(m-1)$-dimensional submanifold and an additional closed remaining set of Hausdorff dimension at most $m-2$.Comment: 74 pages, 1 figure. Comments are welcome

Determination of Fe2+ and Fe3+ species by FIA-CRC-ICP-MS in Antarctic ice samples

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Distribuzione dimensionale di ioni organici e inorganici dell’aerosol Artico: sorgenti e trasporto in una serie temporale di un anno

Con questo studio è stata determinata la distribuzione dimensionale e la concentrazione di specie ioniche e composti di foto-ossidazione dell’α-pinene nell’aerosol Artico con l’obiettivo di investigare sorgenti, processi chimici in atmosfera e di trasporto considerando un anno intero di campionamento. L’aerosol atmosferico è stato prelevato dal 26 febbraio 2018 al 26 febbraio 2019 presso l’osservatorio di Gruvebadet, Ny Ålesund (78°55′03″N, 11°53′39″E, 50 m a.s.l.) con una risoluzione da 6 a 10 giorni. I composti analizzati comprendono i principali ioni inorganici (Cl-, Br-, I-, NO−, SO42−, K+, Mg2+,Na+, NH4+, Ca2+), acidi organici (acido metansolfonico e acidi carbossilici C2–C7) e composti di foto-ossidazione dell’α-pinene (acido pinico e acido cis-pinonico). A causa della vicinanza dal fiordo (Kongsfjorden) in cui si trova il sito del campionamento, l’aerosol campionato è caratterizzato principalmente da particelle derivanti da spray marino (Na+, Cl- e SO42−). Queste specie rappresentano il 74% della somma totale delle specie ioniche studiate. Di grande importanza risulta essere il non sea salt-SO42− che, rispetto al solfato totale, è circa l’85% ed è presente a causa di trasporti a lungo raggio da aree antropizzate, specialmente dall’Eurasia. Composti a concentrazione molto più bassa come acidi carbossilici e composti di foto-ossidazione dell’α-pinene hanno rilevante interesse ambientale per lo studio delle condizioni atmosferiche e dei trasporti a lungo raggio, soprattutto durante l’inverno polare

FiCoS: A fine-grained and coarse-grained GPU-powered deterministic simulator for biochemical networks.

Mathematical models of biochemical networks can largely facilitate the comprehension of the mechanisms at the basis of cellular processes, as well as the formulation of hypotheses that can be tested by means of targeted laboratory experiments. However, two issues might hamper the achievement of fruitful outcomes. On the one hand, detailed mechanistic models can involve hundreds or thousands of molecular species and their intermediate complexes, as well as hundreds or thousands of chemical reactions, a situation generally occurring in rule-based modeling. On the other hand, the computational analysis of a model typically requires the execution of a large number of simulations for its calibration, or to test the effect of perturbations. As a consequence, the computational capabilities of modern Central Processing Units can be easily overtaken, possibly making the modeling of biochemical networks a worthless or ineffective effort. To the aim of overcoming the limitations of the current state-of-the-art simulation approaches, we present in this paper FiCoS, a novel "black-box" deterministic simulator that effectively realizes both a fine-grained and a coarse-grained parallelization on Graphics Processing Units. In particular, FiCoS exploits two different integration methods, namely, the Dormand-Prince and the Radau IIA, to efficiently solve both non-stiff and stiff systems of coupled Ordinary Differential Equations. We tested the performance of FiCoS against different deterministic simulators, by considering models of increasing size and by running analyses with increasing computational demands. FiCoS was able to dramatically speedup the computations up to 855×, showing to be a promising solution for the simulation and analysis of large-scale models of complex biological processes

The rugby side-on tackle: on-field comparison between young and senior international \ue9lite athletes for technique enhancement and injury prevention.

The aim of the present study is to investigate the tackling technique in international \ue9lite young and senior athletes, to highlight differences both in technique effectiveness and ACL injury risk

A 120 000-year record of sea ice in the North Atlantic?

Although it has been demonstrated that the speed and magnitude of recent Arctic sea ice decline is unprecedented for the past 1,450 years, few records are available to provide a paleoclimate context for Arctic sea ice extent. Here we present a 120 kyr record of bromine enrichment from the RECAP ice core, coastal East Greenland, and reconstruct past sea ice conditions in the North Atlantic as far north as the entrance of the Arctic Ocean (50–85° N). Bromine enrichment has been previously employed to reconstruct first-year sea ice (FYSI) in the Canadian Arctic over the last glacial cycle. We find that during the last deglaciation, the transition from multi-year sea ice (MYSI) to FYSI started at ∼ 17.6 kyr, synchronous with sea ice reductions observed in the eastern Nordic seas (Müller and Stein, 2014; Hoff et al., 2016) and with the increase of North Atlantic ocean temperature (Dokken and Jansen, 1999). FYSI reached its maximum extent at 12.4–11.8 kyr, after which open-water conditions started to dominate, as supported by sea ice records from the eastern Nordic seas and the North Icelandic shelf. Our results show that over the last 120,000 years, sea ice extent was greatest during Marine Isotope Stage (MIS) 2 and MIS4, with decreased levels during MIS3 and the onset of the last glacial period (late-MIS5). Sea ice extent during the last 10 kyr (Holocene/MIS1) has been less than at any time in the last 120 kyr