Search Results (1,677)

The present study examines the negative ionospheric response over Europe during two geomagnetic storms on 10–13 May 2024, known as the Mother’s Day geomagnetic superstorm. The first storm, with a peak SYM-H value of −436 nT, occurred in the interval 10–11 May, while the second, less intense storm (SYM-H~−103 nT), followed in the interval 12–13 May. Using data from four European locations, temporal and spatial variations in ionospheric parameters (TEC, foF2, and hmF2) were analyzed to investigate the morphology of the strong negative response. Sharp electron density (Ne) depletion is associated with the equatorward displacement of the Midlatitude Ionospheric Trough (MIT), confirmed by Swarm satellite data. A key finding was the absence of foF2 and hmF2 values over all ionosonde stations during the recovery phase of the storms, likely due to the coupling between the Equatorial Ionization Anomaly (EIA) crests and the auroral ionosphere influenced by the intense uplift of the F layer. Relevant distinct features such as Large-scale Travelling Ionospheric Disturbance (LSTID) signatures and Spread F were also noted, particularly during the initial and main phase of the first storm over high midlatitude regions. Regional effects varied, with high European midlatitudes exhibiting different features compared to lower European latitude areas. Full article

In the modern digital age, organizations face unprecedented challenges and possibilities while managing the intricacies of digital transformation. Accelerated technological developments, changing customer preferences, heightened competition, and dynamic regulatory environments necessitate companies to synchronize their business goals with technological innovations. Leadership is crucial in steering businesses through changes, requiring a deep understanding of change processes and the capacity to adjust leadership accordingly. This research addresses the central question: How does leadership effectively promote organizational digital transformation? The study examines how leaders can effectively promote the adoption of advanced technologies and the promotion of innovation, by first exploring the nature of digital transformation within organizations and then analyzing the evolving dynamics of leadership in this context. An integrative review of the Web of Science (WoS) and Scopus databases was conducted, using the search terms: “Leadership” and “Digital Transformation”. The findings emphasize that effective leadership is crucial for managing the minutiae of digital transformation, integrating technology into organizational processes to facilitate learning, collaboration, and agility, enabling companies to adapt to market shifts, reduce uncertainty, and enhance decision-making for sustainable growth. By using the right tools and with the right frequency, leaders may develop team cohesion—even at a distance. Attentive digital-age leaders will know how to leverage the right mechanisms, and herein, we hope to give some indication of how that may be achieved, so that digital transformation increases rather than decreases team motivation levels. Full article

Solar eclipses present a valuable opportunity for controlled in situ ionosphere studies. This work explores the response of the upper atmosphere’s F-layer during the total eclipse of April 8, 2024, which was primarily visible across North and South America. Employing a multi-instrument approach, we analyze the impact on the ionosphere’s Total Electron Content (TEC) and Very Low Frequency (VLF) signals over a three-day period encompassing the eclipse (April 7 to 9, 2024). Ground-based observations leverage data from ten International GNSS Service (IGS)/Global Positioning System (GPS) stations and four VLF stations situated along the eclipse path. We compute vertical TEC (VTEC) alongside temporal variations in the VLF signal amplitude and phase to elucidate the ionosphere’s response. Notably, the IGS station data reveal a decrease in VTEC during the partial and total solar eclipse phases, signifying a reduction in ionization. While VLF data also exhibit a general decrease, they display more prominent fluctuations. Space-based observations incorporate data from Swarm and COSMIC-2 satellites as they traverse the eclipse path. Additionally, a spatiotemporal analysis utilizes data from the Global Ionospheric Map (GIM) database and the DLR’s (The German Aerospace Center’s) database. All space-based observations consistently demonstrate a significant depletion in VTEC during the eclipse. We further investigate the correlation between the percentage change in VTEC and the degree of solar obscuration, revealing a positive relationship. The consistent findings obtained from this comprehensive observational campaign bolster our understanding of the physical mechanisms governing ionospheric variability during solar eclipses. The observed depletion in VTEC aligns with the established principle that reduced solar radiation leads to decreased ionization within the ionosphere. Finally, geomagnetic data analysis confirms that external disturbances do not significantly influence our observations. Full article

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a chronic condition marked by hyperglycemia, which can affect metabolic, vascular, and hematological parameters. A low-carbohydrate, high-fat (LCHF) diet has been shown to improve glycemic control and blood pressure regulation. Exercise in hypoxia (EH) enhances insulin sensitivity, erythropoiesis, and angiogenesis. The combination of LCHF and EH may offer a promising strategy for managing T2DM and hypertension (HTN), although evidence remains limited. This study aimed to assess the effects of an eight-week normobaric EH intervention at 3000 m simulated altitude combined with an LCHF diet on hematological and lipid profiles, inflammation, and blood pressure in older patients with T2DM and HTN. Methods: Forty-two diabetic patients with HTN were randomly assigned to three groups: (1) control group (control diet + exercise in normoxia), (2) EH group (control diet + EH), and (3) intervention group (EH+LCHF) Baseline and eight-week measurements included systolic, diastolic, and mean blood pressure (SBP, DBP, MAP), hematological and lipid profiles, and inflammation biomarkers. Results: Blood pressure decreased after the intervention (p < 0.001), with no significant differences between groups (SBP: p = 0.151; DBP: p = 0.124; MAP: p = 0.18). No differences were observed in lipid profile or C-reactive protein levels (p > 0.05). Mean corpuscular hemoglobin (MCH) increased in the EH group (p = 0.027), while it decreased in the EH+LCHF group (p = 0.046). Conclusions: Adding hypoxia or restricting carbohydrates did not provide additional benefits on blood pressure in T2DM patients with HTN. Further elucidation of the mechanisms underlying hematological adaptations is imperative. Trial registration number: NCT05094505. Full article

Due to space and energy restrictions, lightweight autonomous underwater vehicles (AUVs) are usually fitted with low-power processing units, which limits the ability to run demanding applications in real time during the mission. However, several robotic perception tasks reveal a parallel nature, where the same processing routine is applied for multiple independent inputs. In such cases, leveraging parallel execution by offloading tasks to a GPU can greatly enhance processing speed. This article presents a collection of generic matrix manipulation kernels, which can be combined to develop parallelized perception applications. Taking advantage of those building blocks, we report a parallel implementation for the 3DupIC algorithm—a probabilistic scan matching method for sonar scan registration. Tests demonstrate the algorithm’s real-time performance, enabling 3D sonar scan matching to be executed in real time onboard the EVA AUV. Full article

Precision agriculture seeks to optimize crop yields while minimizing resource use. A key challenge is achieving uniform pesticide spraying to prevent crop damage and environmental contamination. Water-sensitive paper (WSP) is a common tool used for assessing spray quality, as it visually registers droplet impacts through color change. This work introduces a smartphone-based solution for capturing WSP images within vegetation, offering a tool for farmers to assess spray quality in real-world conditions. To achieve this, two approaches were explored: classical computer vision techniques and machine learning (ML) models (YOLOv8, Mask-RCNN, and Cellpose). Addressing the challenges of limited real-world data and the complexity of manual annotation, a programmatically generated synthetic dataset was employed to enable sim-to-real transfer learning. For the task of WSP segmentation within vegetation, YOLOv8 achieved an average Intersection over Union of 97.76%. In the droplet detection task, which involves identifying individual droplets on WSP, Cellpose achieved the highest precision of 96.18%, in the presence of overlapping droplets. While classical computer vision techniques provided a reliable baseline, they struggled with complex cases. Additionally, ML models, particularly Cellpose, demonstrated accurate droplet detection even without fine-tuning. Full article

Thermoelectric heat dissipation systems offer unique advantages over conventional systems, including vibration-free operation, environmental sustainability, and enhanced controllability. This study examined the benefits of incorporating a thermoelectric cooler (TEC) into conventional heat sinks and investigated strategies to improve heat dissipation efficiency. A theoretical model introducing a dimensionless evaluation index () is proposed to assess the system’s performance, which measures the ratio of the heat dissipation density of a conventional heat dissipation system to that of a thermoelectric heat dissipation system. Here, we subjectively consider 0.9 as a cutoff, and when , the thermoelectric heat dissipation system shows substantial superiority over conventional ones. In contrast, for , the advantage of the thermoelectric system weakens, making conventional systems more attractive. This analysis examined the effects of engineering leg length (), the heat transfer allocation ratio (), and temperature difference () on heat dissipation capabilities. The results indicated that under a fixed heat source temperature, heat sink temperature, and external heat transfer coefficient, an optimal engineering leg length exists, maximizing the system’s heat dissipation performance. Furthermore, a detailed analysis revealed that the thermoelectric system demonstrated exceptional performance under small temperature differences, specifically when the temperature difference was below 32 K with the current thermoelectric (TE) materials. For moderate temperature differences between 32 K and 60 K, the system achieved optimal performance when . This work establishes a theoretical foundation for applying thermoelectric heat dissipation systems and provides valuable insights into optimizing hybrid heat dissipation systems. Full article

The autonomous navigation of unmanned ground vehicles (UGVs) in unstructured environments, such as agricultural or forestry settings, has been the subject of extensive research by various investigators. The navigation capability of a UGV in unstructured environments requires considering numerous factors, including the quality of data reception that allows reliable interpretation of what the UGV perceives in a given environment, as well as the use these data to control the UGV’s navigation. This article aims to study different PID control algorithms to enable autonomous navigation on a robotic platform. The robotic platform consists of a forestry tractor, used for forest cleaning tasks, which was converted into a UGV through the integration of sensors. Using sensor data, the UGV’s position and orientation are obtained and utilized for navigation by inputting these data into a PID control algorithm. The correct choice of PID control algorithm involved the study, analysis, and implementation of different controllers, leading to the conclusion that the Vector Field control algorithm demonstrated better performance compared to the others studied and implemented in this paper. Full article

Lung cancer stands as the most prevalent and deadliest type of cancer, with adenocarcinoma being the most common subtype. Computed Tomography (CT) is widely used for detecting tumours and their phenotype characteristics, for an early and accurate diagnosis that impacts patient outcomes. Machine learning algorithms have already shown the potential to recognize patterns in CT scans to classify the cancer subtype. In this work, two distinct pipelines were employed to perform binary classification between adenocarcinoma and non-adenocarcinoma. Firstly, radiomic features were classified by Random Forest and eXtreme Gradient Boosting classifiers. Next, a deep learning approach, based on a Residual Neural Network and a Transformer-based architecture, was utilised. Both 2D and 3D CT data were initially explored, with the Lung-PET-CT-Dx dataset being employed for training and the NSCLC-Radiomics and NSCLC-Radiogenomics datasets used for external evaluation. Overall, the 3D models outperformed the 2D ones, with the best result being achieved by the Hybrid Vision Transformer, with an AUC of 0.869 and a balanced accuracy of 0.816 on the internal test set. However, a lack of generalization capability was observed across all models, with the performances decreasing on the external test sets, a limitation that should be studied and addressed in future work. Full article

The Feline Immunodeficiency Virus (FIV) is a lentivirus belonging to Retroviridae family that affects feline immune cells, causing a progressive immunosuppression by depleting CD4+ T-lymphocytes, similarly to the acquired immune deficiency syndrome (AIDS) in humans caused by human immunodeficiency virus (HIV). Diagnosis is usually performed by clinicians using rapid Enzyme-Linked Immunosorbent Assay (ELISA) or lateral flow tests that detect FIV antibodies. The aim of this work was the development of FIVCHECK Ab ELISA, a new rapid indirect assay for the detection of FIV antibodies in feline serum/plasma samples; FIVCHECK Ab ELISA was developed after a meticulous set-up and cut-off analysis through several methods, including the Youden’s index and ROC curve, to achieve the best test performance. The new kit was validated by testing 115 feline sera (38 positives and 77 negatives for FIV antibodies) against the ELISA rapid test SNAP FIV/FeLV Combo (IDEXX). Moreover, 103 sera (28 positives and 75 negatives) were also analyzed with two other rapid indirect ELISAss, INgezim FIV (Gold Standard Diagnostics) and VetLine FIV (NovaTec); FIVCHECK Ab ELISA agreed at 100% with SNAP (100% sensitivity, 95% confidence interval (CI): 88.5–100%; 100% specificity, 95% CI: 94.0–100%), 100% with INgezim FIV and 92.2% with VetLine FIV. Intra- and inter-assay accuracy and precision gave coefficients of variation lower than 10%. The new ELISA is a simple and quick test that provides reliable results for veterinary clinics and practices. Full article

Refrigeration is vital in daily life and industries, traditionally relying on single-system cooling. The two predominant kinds of single-system cooling are vapor compression refrigeration (VCR) and thermoelectric cooling (TEC). Each of these two single systems has its own disadvantages, such as higher input energy requirements and lower efficiency. However, the effect of the integration of VCR and TEC for achieving higher cooling performance with lower energy input has not been well studied and reported in the existing literature. Therefore, the aim of this study is to conduct a thorough investigation into an integrated refrigeration system that combines VCR and TEC. This integration allows switching between systems based on specific requirements, leveraging the high coefficient of performance (COP) of VCR and the benefits of TEC. Three configurations have been studied, and each of them has three operating conditions: VCR alone, TEC alone, and TEC hybrid with VCR. Configuration I corresponds to the results from the individual refrigeration test. In Configuration II, the hot end of the thermoelectric cooling module is installed at the insulation layer between the TEC layer and the VCR compartment. In Configuration III, the cold end of the thermoelectric cooling module is positioned at the insulation layer between the TEC layer and the VCR compartment. Configuration III of the integrated system demonstrated good performance by reducing the time required to reach the target temperature. It took 40 min for TEC alone to reach a temperature of 11.1 °C, 13 min for VCR alone, and only 9.6 min for a hybrid system. The hybrid system shows increased versatility and potential for future applications, providing valuable insight into optimizing advanced cooling technologies. Furthermore, from an economic and sustainability standpoint, the proposed hybrid refrigeration system is advantageous and ambitious as it offers superior cooling capacity and greater efficiency than current refrigeration systems. Full article

An accurate estimation of Differential Code Bias (DCB) is essential for high-precision applications of the Global Navigation Satellite System (GNSS) and for the precise determination of GNSS-derived total electron content (TEC). This study leverages BeiDou Navigation Satellite System (BDS) and Global Positioning System (GPS) dual-frequency observations of the China Seismo-electromagnetic Satellite (CSES) from day of the year (DOY) 201 to DOY 232 in 2018, we evaluate the quality of CSES onboard GNSS observations, improve the data preprocessing method, and use the least-squares to estimate DCBs for both GNSS satellites and CSES receivers. A comprehensive analysis of the estimation accuracy is presented, revealing that DCBs for BDS satellites, derived from joint BDS and GPS observations, exhibit superior consistency compared to those from single BDS observations. Notably, the stability of DCBs for the CSES BDS receiver as well as for BDS GEO, IGSO, and MEO satellites has been significantly enhanced by 70%, 14%, 22%, and 23%, respectively. Conversely, the consistency of GPS satellite DCBs estimated from joint observations shows a decline when compared to the DCB products from the Center for Orbit Determination in Europe (CODE) and the Chinese Academy of Sciences (CAS). When fewer than nine satellites are tracked daily and nighttime observations are under 25%, estimation errors increase. The optimal DCB estimation is achieved with a cutoff elevation angle set at 10°, with monthly mean DCB values for CSES GPS and BDS receivers determined to be −2.193 ns and −1.099 ns, respectively, accompanied by root mean square errors (RMSEs) of 0.10 ns and 0.31 ns. The highest accuracy of DCBs estimated by the single-GPS scheme is corroborated by examining the occurrence of negative vertical total electron content (VTEC) percentages. Full article

Genetically determined left ventricular excessive trabeculation (LVET) has a wide clinical spectrum ranging from asymptomatic subjects to severe heart failure with arrhythmias and thromboembolic events. Unlike other cardiomyopathies, the relatives of LVET patients never reach the spotlight of guidelines and clinical practice, although these family members can be often affected by these conditions. Thus, we aimed to investigate the relatives of LVET by multidimensional analysis, such as genetic testing, ECG and cardiac ultrasound (ECHO). We included 55 blood relatives from the family of 18 LVET patients (male = 27, age = 44 ± 20.8y), who underwent anamnesis registration. With Sanger sequencing, the relatives were classified into genetically positive (GEN-pos) and unaffected (GEN-neg) subgroups. In addition to regular ECG parameters, Sokolow-Lyon Index (SLI) values were calculated. 2D ECHO images were analysed with TomTec Arena, evaluating LV volumetric, functional (EF) and strain parameters. Individuals were categorized into JENNI-pos and JENNI-neg morphological subgroups according to the Jenni LVET ECHO criteria. Family history showed frequent involvement (arrhythmia 61%, stroke 56%, syncope 39%, sudden cardiac death 28%, implanted device 28%), as well as personal anamnesis (subjective symptoms 75%, arrhythmias 44%). ECG and ECHO parameters were within the normal range. In terms of genetics, 78% of families and 38% of relatives carried the index mutation. LV_SLI and QT duration were lower in the GEN-pos group; ECHO parameters were comparable in the subgroups. Morphologically, 33% of the relatives met Jenni-LVET criteria were genetically affected and showed lower LV_EF values. The frequently found genetic, morphological and clinical involvement may indicate the importance of screening and, if necessary, regular follow-up of relatives in the genetically affected LVET population. Full article

In this paper, the abrasive effects of lunar simulant regoliths (LHS-1, LMS-1) have been investigated. Sealing performance of different sealant pin materials on stainless steel has been tested by the pin-on-disc method. Pin materials included block types such as pure polytetrafluoroethylene (PTFE), composite PTFE, as well as braided PTFE and hybrid-composite braided PTFE. Tribological properties were evaluated based on measured friction, wear, surface roughness and scanning electron micrographs. Most significant differences were observed in the sealing effect of the pins between the braided and the block-type pin materials. The stainless steel/pin pairs showed significantly higher (0.4–0.5) friction coefficients for the braided pins than the block ones (0.2–0.3), while there was not a significant difference in the abrasive effect of the different lunar regoliths. Although significant wear of the steel part occurred only with the block-type pins, this disadvantage was apparent in comparison with the braided pins. The abrasive particles caused deformation and eventually complete disintegration of the braided pins. Both the coefficient of friction and the wear could be estimated by a multiple linear regression model, in which different regolith size was the dominant independent parameter for the various pins. Full article

This article discusses outcomes of the Polish–Chinese project dedicated to establishing multi-GNSS near-real-time ionospheric services. ARTEMIS (Advanced methodology development for Real-Time Multi-constellation (BDS, Galileo and GPS) Ionosphere Services) was a response to increasing GNSS data availability, including Galileo and BeiDou observations on the one hand and growing interest in high-quality ionospheric products on the other. The project resulted in elaborating methodologies to monitor the ionospheric Total Electron Content (TEC) and its fluctuations (ROTI index) based on a full multi-GNSS approach and establishing pilot real-time web services in a global and regional approach. The project’s outcomes are to be included in the International GNSS Service (IGS) and International Reference Ionosphere (IRI) in the near future. This article presents real-time ionospheric products developed under the ARTEMIS project and evaluates their performance using independent techniques such as DORIS observations and altimetry with regard to other existing products. The Discussion section also includes an evaluation of ARTEMIS products in positioning applications. Full article