Search

The Arctic region is undergoing significant changes in maritime accessibility. This study investigates observed ship trajectories from 2013 to 2020 to demonstrate the recent trends of Arctic traffic. A notable surge in maritime activities has been observed, particularly during summer months, driven by economic interests and the increasing popularity of existing routes. Unique patterns in the northern Barents Sea have been observed where ships favour different routes based on seasonal ice conditions. Another contribution from this work is the validation of the Arctic Traffic Accessibility Model (ATAM) using the observed ship traffic data. Results show that the ATAM model underestimates the accessibility and vessel travel speed. This is largely due to outdated model parameters. The predefined ice multipliers and calculation of ice numerals used in the ATAM may not accurately reflect real-world conditions.

Background: Seasonal allergic rhinoconjunctivitis (SAR) is a worldwide health problem, especially in Westernized countries. Previous studies of the “Panallergens in Pediatrics” (PAN-PED) cohort found that molecular spreading (ie, the progressive increase in serum specific IgE antibody levels) of the IgE response to the grass pollen, Phleum pratense, molecules is directly associated with polysensitization to pollen in general.The research question is aimed at verifying whether this association can also be detected for non-pollen allergens, specifically Dermatophagoides pteronyssinnus (D.pt), to better understand the relationship between a perennial allergen (D.pt) and a seasonal allergen (Phleum pratense).To this end, our first objective was to analyze the biobank of the PAN-PED cohort serum by measuring the IgE levels to D.pt and its major recombinant molecules (Der p1, Der p2, Der p23); subsequently we investigated their correlation towards Phleum pratense IgE response, studying also the relationship between the molecular spreading of these 2 different allergens. Methods: Among 1120 patients positive to Phleum pratense, 638 were also sensitized to D.pt. Patients underwent skin prick tests (SPT) for inhalant extracts, and their serum was tested for total IgE (tIgE), and sIgE to pollen and perennial allergens. Considering the molecular allergen detection through the component resolved diagnosis (CRD), out of 638 patients, 146 were further investigated by performing IgE tests of the 3 major D.pt. molecules: Der p1, Der p2, and Der p23. Results: We found that a broader molecular response to Phleum pratense molecules, assessed by CRD, was associated with higher tIgE levels, polysensitization to pollens, and higher IgE levels to pollens, but also to lower IgE levels to D.pt and lower degree of sensitization to rDer p1, r Der p2, and rDer p23. In a multivariate linear model, the number of Phleum pratense molecules recognized by IgE was still inversely associated with the IgE level to D.pt extract. Conclusions: The main finding of this study was the detection of an inverse association, never described in the literature, between the molecular spreading of the IgE response to Phleum pratense and the IgE response to D.pt. This led us to speculate on the etiopathogenetic hypothesis according to which, among the majority of pollen allergic patients, a strong and molecularly diversified IgE response may be limited to pollen allergens and may be preventing or contrasting the development of an equally strong and diversified IgE sensitization to D.pt molecules. The biological mechanisms underlying this phenomenon deserve to be investigated.

ABSTRACTHurricane Ian in 2022 was a destructive category 4 Atlantic hurricane striking the state of Florida, which caused hundreds of deaths and injuries, catastrophic property damage, and an economic loss of more than $112 billion. Before the landfall of Ian in Florida, the state government issued evacuation orders in high-risk zones to reduce casualties and injuries. However, there is limited data available to monitor the actual evacuation patterns and compliance with the evacuation orders at a large geographic scale. This study utilizes human mobility data (i.e. SafeGraph Weekly Pattern) to analyse the spatial patterns of evacuation during Hurricane Ian in 2022. The objectives of the study include three key aspects: 1) proposing an analytical workflow that utilizes human mobility data to detect mobility patterns in disasters and other emergency events; 2) identifying significant evacuation patterns, and 3) revealing the spatial variations in the compliance with evacuation orders in the affected areas. Using data science and spatial analysis techniques, this study detected notable changes in population movements, both within Florida and nationwide, which are potentially linked to the hurricane-induced population evacuation. The distance decay pattern of population flows from Florida demonstrates a propensity for individuals to relocate to nearby areas during the hurricane. Furthermore, the increase in population outflows from the impacted areas suggests the effectiveness of mandatory evacuation orders. A more pronounced increase in outflows from designated mandatory evacuation areas points to the public awareness of the evacuation zone designation. This study provides large-scale, fine-resolution analysis of evacuation behaviours in natural disasters which cannot be easily detected in traditional data sources. The analytical workflows provide actionable tools for government agencies and policymakers to evaluate the effectiveness of evacuation orders and improve evacuation plans in future disasters.

ABSTRACTThis research evaluates Laser Powder Directed Energy Deposition (LP-DED) for producing fine feature internal microchannels. This study is focused on enhancing and characterising the surfaces of microchannels produced using techniques such as abrasive flow machining, chemical milling, chemical mechanical polishing, electrochemical machining, and thermal energy method to modify internal surfaces of microchannels made from NASA HR-1 Fe-Ni-Cr alloy. Flow testing for discharge coefficient measurement is conducted on processed microchannel samples, followed by characterisation through optical microscopy, Scanning Electron Microscopy (SEM), and Computed Tomography. Findings reveal variations in surfaces due to powder adherence, melt pool undulations, and polishing mechanisms. The study emphasises the significance of removing material equivalent to the mean powder diameter to reduce surface roughness and impact the discharge coefficient. The research proposes a ratio for planarising roughness and waviness peak height and density, offering insights for tailored surface adjustments in specific applications requiring reduced flow resistance.HighlightsInternal microchannels with thin-walls were fabricated using the laser powder directed energy deposition process.Various surface enhancements and polishing processes were developed to modify the surface texture of the LP-DED channels.Flow testing was conducted to determine the discharge coefficient.Post-test characterisation was completed to obtain cross sectional area, perimeter, surface texture, and general surface condition to analyse results.Ratio of roughness and waviness peak and density (Spk/Spd and Wp/WPc) is proposed as a relevant surface characterisation parameter.Tailored surface modifications for specific end-use applications.

Background Ticagrelor is recommended over clopidogrel in acute coronary syndrome based on the results of the PLATO (Study of Platelet Inhibition and Patient Outcomes) trial. We aimed to emulate PLATO in older adults with and without frailty and with acute coronary syndrome treated with percutaneous coronary intervention. Methods and Results We created a new‐user cohort of Medicare fee‐for‐service beneficiaries aged ≥65 years hospitalized for acute coronary syndrome from 2014 to 2018 and initiated ticagrelor or clopidogrel following percutaneous coronary intervention. Frailty was defined using a validated claims‐based frailty index ≥0.25. Coprimary outcomes were major adverse cardiovascular events and major bleeding. Follow‐up began on the date of first outpatient prescription for ticagrelor or clopidogrel and ended on the earliest date for an outcome event, death, discontinuation of the index drug, or disenrollment from Medicare. The study included 42 843 older adults; 23% were frail. After propensity score matching, the rates of major adverse cardiovascular events per 100 person‐years comparing ticagrelor versus clopidogrel groups were 7.8 and 7.3 in the frail cohort (hazard ratio [HR], 1.07 [95% CI, 0.84–1.36]) and 3.7 and 4.2 in the nonfrail cohort (HR, 0.87 [95% CI, 0.75–1.02]). The corresponding rates of major bleeding were 4.3 and 3.8 in the frail cohort (HR, 1.12 95% CI, [0.80–1.56]) and 2.2 and 1.8 in the nonfrail cohort (HR, 1.22 [95% CI, 0.98–1.51]). Conclusions There was a trend toward a modest reduction in risk of major adverse cardiovascular events and a trend toward a modest increase in risk of major bleeding with ticagrelor compared with clopidogrel in the nonfrail cohort. There was insufficient evidence for the benefit of ticagrelor in frail older adults.

PEMFCs play a key role in the energy transition scenarios thanks to the zero emissions, versatility, and power density. PEMFC performances are improved optimizing water management to ensure proper ion transport: it is well known that a well-balanced water content avoids either electrodes flooding or membrane drying, causing gas starvation at the active sites or low proton conductivity, respectively. In this paper, an analytical formulation for water transport dynamics within the membrane, derived from membrane water balance, is proposed to overcome the limitations of PEM dynamics model largely adopted in the literature. The dynamics is simulated thanks to the introduction of a characteristic time with a closed analytical form, which is general and easily implementable for any application where both low computational time and high accuracy are required. Furthermore, the net water molar fluxes at the membrane boundaries can be easily computed as well for a cell’s simulation. The analytical formulation has a strong dependency on the operative conditions, as well as physical parameters of the membrane itself. From the proposed formulation, for a 200 µm membrane, the characteristic time can vary from 5 s up to 50 s; this example shows how control strategies must consider PEM dynamic behavior.

The Greenland Ice Sheet (GrIS) has been contributing directly to sea level rise, and this contribution is projected to accelerate over the next decades. A crucial tool for studying the evolution of surface mass loss (e.g., surface mass balance, SMB) consists of regional climate models (RCMs), which can provide current estimates and future projections of sea level rise associated with such losses. However, one of the main limitations of RCMs is the relatively coarse horizontal spatial resolution at which outputs are currently generated. Here, we report results concerning the statistical downscaling of the SMB modeled by the Modèle Atmosphérique Régional (MAR) RCM from the original spatial resolution of 6 km to 100 m building on the relationship between elevation and mass losses in Greenland. To this goal, we developed a geospatial framework that allows the parallelization of the downscaling process, a crucial aspect to increase the computational efficiency of the algorithm. Using the results obtained in the case of the SMB, surface and air temperature are assessed through the comparison of the modeled outputs with in situ and satellite measurement. The downscaled products show a considerable improvement in the case of the downscaled product with respect to the original coarse output, with the coefficient of determination (R2) increasing from 0.868 for the original MAR output to 0.935 for the SMB downscaled product. Moreover, the value of the slope and intercept of the linear regression fitting modeled and measured SMB values shifts from 0.865 for the original MAR to 1.015 for the downscaled product in the case of the slope and from the value −235 mm w.e. yr−1 (original) to −57 mm w.e. yr−1 (downscaled) in the case of the intercept, considerably improving upon results previously published in the literature.

Abstract This manuscript aims to present and evaluate the applicability of combining optical line-of-sight (LoS) navigation with crosslink radiometric navigation for deep-space cruising distributed space systems. To do so, a set of four distributed space systems architectures is presented, and for each of those, the applicability of the combination is evaluated, comparing it to the baseline solutions, which are based on only optical navigation. The comparison is done by studying the performance in a circular heliocentric orbit in seven different time intervals (ranging from 2024 to 2032) and exploiting the observation of all the pairs of planets from Mercury to Saturn. The distance between spacecraft is kept around 200 km. Later, a NEA mission test case is generated in order to explore the applicability to a more realistic case. This analysis shows that the technique can also cope with a variable inter-satellite distance, and the best performance is obtained when the spacecraft get closer to each other.

This work focuses on the well-known issue of mass conservation in the context of the finite element technique for computational fluid dynamic simulations. Specifically, non-conventional finite element families for solving Navier–Stokes equations are investigated to address the mathematical constraint of incompressible flows. Raviart–Thomas finite elements are employed for the achievement of a discrete free-divergence velocity. In particular, the proposed algorithm projects the velocity field into the discrete free-divergence space by using the lowest-order Raviart–Thomas element. This decomposition is applied in the context of the projection method, a numerical algorithm employed for solving Navier–Stokes equations. Numerical examples validate the approach’s effectiveness, considering different types of computational grids. Additionally, the presented paper considers an interface advection problem using marker approximation in the context of multiphase flow simulations. Numerical tests, equipped with an analytical velocity field for the surface advection, are presented to compare exact and non-exact divergence-free velocity interpolation.

The volume of fluid (VOF) method is a popular technique for the direct numerical simulations of flows involving immiscible fluids. A discrete volume fraction field evolving in time represents the interface, in particular, to compute its geometric properties. The height function method (HF) is based on the volume fraction field, and its estimate of the interface curvature converges with second-order accuracy with grid refinement. Data-driven methods have been recently proposed as an alternative to computing the curvature, with particular consideration for a well-balanced input data set generation and symmetry preservation. In the present work, a two-layer feed-forward neural network is trained on an input data set generated from the height function data instead of the volume fraction field. The symmetries for rotations and reflections and the anti-symmetry for phase swapping have been considered to reduce the number of input parameters. The neural network can efficiently predict the local interface curvature by establishing a correlation between curvature and height function values. We compare the trained neural network to the standard height function method to assess its performance and robustness. However, it is worth noting that while the height function method scales perfectly with a quadratic slope, the machine learning prediction does not.

Trichuris vulpis is a parasite of the large intestine of canids and has a global distribution. Despite its well-established epidemiology, the question of its pathogenicity in dogs remains debated. It has been suggested that younger age and concurrent infection with Ancylostoma caninum may be responsible for more severe clinical presentations. This retrospective study aimed to describe the clinical and diagnostic features of T. vulpis-infected dogs and to compare these findings with dogs infected with both T. vulpis and other intestinal parasites (poly-infected dogs). Forty-five dogs were included, with twenty-five being solely infected by T. vulpis and twenty poly-infected dogs. Only weight loss was more frequent (p = 0.006) in poly-infected dogs compared to T. vulpis mono-infected dogs. No significant differences were observed in laboratory abnormalities between mono-infected and poly-infected dogs. Only diarrhea was more frequent (p = 0.007) in younger dogs compared to adults. The egg shedding pattern was significantly higher (p = 0.04) among adult dogs compared to young ones, and there was a significant positive correlation between egg shedding and age (r = 0.41; p = 0.005). These findings suggest that T. vulpis might be responsible for both clinical signs and laboratory abnormalities in dogs, irrespective of the host’s age and the presence of other intestinal parasites.

This study introduces numerical advancements in an alternative design for the Super Proton Synchrotron (SPS) Beam Dump Facility (BDF) at the European Laboratory for Particle Physics (CERN). The design envisions a high-power operation target made of flowing liquid lead. The proposed BDF is a versatile facility for both beam-dump-like and fixed-target experiments. The target behavior is studied, assuming a proton beam with a momentum of 400 GeV/c, a pulse frequency of 1/7.2 Hz, and an average beam power of 355 kW. Using various Computational Fluid Dynamics (CFD) codes, we evaluate the behavior of liquid lead and predict the thermal stress on the target vessel induced by the pulsed heat source generated by the charged particle beam. The comparison increases the reliability of the results, investigating the dependencies on the CFD modeling approach. The beam is a volumetric heat source with data from the beam-lead interaction simulations provided by the European Laboratory for Particle Physics and obtained with a Monte Carlo code. Velocity field and stress profiles can enhance the design of the lead loop and verify its viability and safety when operated with a liquid metal target.