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Found 6278 publications
COVID-19 Alters Respiratory Function Associations in High-Level Athletes
Publication Name: Medicina Lithuania
Publication Date: 2025-09-01
Volume: 61
Issue: 9
Page Range: Unknown
Description:
Background and Objectives: Coronavirus disease 2019 (COVID-19) has affected multiple physiological systems, including respiratory function, which is critical for athletic performance. Although alterations in pulmonary dynamics have been observed in high-level athletes recovering from COVID-19, the effects on respiratory function remain unclear. In this context, the present study aimed to examine the impact of COVID-19 on the interrelationships among respiratory function parameters in high-level athletes. Materials and Methods: Sixty-eight high-level athletes participated in the present study, including 34 with a history of COVID-19 and 34 controls without prior infection. Respiratory function and respiratory muscle strength were assessed using a digital spirometer (Pony FX, Cosmed, Italy). Key variables included Forced Vital Capacity (FVC), Peak Expiratory Flow (PEF), Maximum Voluntary Ventilation (MVV), Forced Expiratory Volume in one second (FEV1 ), and Maximum Inspiratory/Expiratory Pressure (MIP/MEP). Results: High-level athletes with prior COVID-19 infection exhibited significant differences in the correlations (p < 0.05) between FVC and PEF, FVC and MVV, FEV1 and FEV1 /FVC, and MIP and MVV compared to controls. Conclusions: These findings suggest that COVID-19 can disrupt the interrelationships among respiratory function parameters in high-level athletes, highlighting the need for further longitudinal investigations.
Open Access: Yes
Temporal dynamics of geopolitical risk: An empirical study on energy commodity interest-adjusted spreads
Publication Name: Energy Economics
Publication Date: 2025-01-01
Volume: 141
Issue: Unknown
Page Range: Unknown
Description:
The functioning of energy markets is essential for global stability and is heavily influenced by geopolitical risks. Understanding these risks is critical for policymakers, market analysts, and nations. This study investigates the impact of geopolitical risks and their components on the futures markets of WTI crude oil and natural gas, utilizing time and frequency connectedness analysis along with impulse response function methods. The analysis is based on a dataset comprising daily prices of spot and futures contracts (across various maturities) as well as treasury yields. Our findings reveal that geopolitical risks have a significant, negative impact on the interest-adjusted spread of WTI crude oil. In contrast, the interest-adjusted spread of natural gas futures (NGF) displays a more complex pattern: while short-term maturities show an insignificant response, long-term maturities exhibit a significant reaction. Spillover effects are more pronounced in the short term but tend to weaken over longer horizons. This study underscores the dynamic influence of geopolitical risks on both key energy markets. Its findings offer a practical framework for risk management, equipping market participants and policymakers with valuable insights to better understand and respond to geopolitical risks in the energy sector.
Open Access: Yes
Determination of Natural Blood Plasma Melatonin Concentration of Tsigai Ewes Characteristic for Gestation and Early Postpartum Period Between Autumnal Equinox and Winter Solstice
Publication Name: Veterinary Sciences
Publication Date: 2025-04-01
Volume: 12
Issue: 4
Page Range: Unknown
Description:
Melatonin is a special hormone with many functions. Its production in human and animal organisms is particularly seasonal and related to physiological processes. This study monitors blood plasma melatonin concentration in sheep during the whole gestation and early post-partum period, taking into account the effect of the season that has been less studied so far and in certain details for the first time. It proves that nocturnal plasma melatonin concentration in pregnant ewes increases between the autumnal equinox and the winter solstice in Central Europe in the Northern Hemisphere. It observes that nocturnal plasma melatonin concentration (between 18:00 p.m. and 06:00 a.m.) in pregnant ewes follows a less pronounced variation. Furthermore, it provides proof that nocturnal plasma melatonin concentration in pregnant ewes does not change as pregnancy progresses. It is the first to report that nocturnal plasma melatonin concentration decreases to the same level in ewes and new-born lambs immediately after birth, without nighty fluctuations.
Open Access: Yes
The Triple Threat to Our Environment: Economic, Non-Economic, and Demographic Factors Driving Ecological Footprint in Nuclear-Power Countries
Publication Name: Economies
Publication Date: 2025-04-01
Volume: 13
Issue: 4
Page Range: Unknown
Description:
This study examines how economic growth, travel, global connection, and changes in population impact the environmental footprint in seven countries, including Russia, the US, China, France, the UK, Pakistan, and India, from 1995 to 2023. The results show a significant link between Granger’s environmental impact and some economic, non-economic, and population factors in these countries. According to the study, environmental impacts result primarily from economic expansion and tourism revenue generation. The essential activities in economic development frequently result in significant ecological deficits through natural resource depletion, land alterations, and environmental releases. Business enlargement and tourism income commonly bring about deforestation while causing both pollution and habitat damage, thus showing why sustainable practices must exist to protect nature during economic development. We also have to consider factors other than economics, such as total income from natural resources and using nuclear power early. Additionally, how many people live in a particular area and the number of children born contribute to these footprints. Also, this study shows how economic, non-economic and demographic issues can indicate what harm the environment might face later. This is especially important in countries that use nuclear energy extensively. The report suggests different ways to solve this problem. These include advocating for sustainable tourism practices, directing research efforts towards nuclear energy, supporting renewable energy initiatives, promoting family planning and education, and raising public awareness. The aim is to reduce the environmental harm caused by nuclear energy and promote a more sustainable future.
Open Access: Yes
A New Approach to Breast Specimen Orientation: Avoiding Pitfalls with the Specimen Plate Concept
Publication Name: Current Oncology
Publication Date: 2024-08-01
Volume: 31
Issue: 8
Page Range: 4589-4598
Description:
Accurate specimen marking is crucial during breast cancer surgery to avoid misorientation, which can lead to inadequate re-excision and tumor recurrence. We studied the marking methods at various breast cancer centers to create a tool that would prevent specimen misorientation. An online questionnaire was used to survey marking procedures at major breast cancer centers in Hungary, and a tool was developed using a troubleshooting method. Twelve out of twenty units responded (60%). Nine use an institutionally standardized marking system. Less than half of the surgical teams found specimen mammograms to be unambiguous. In more than 70% of departments, pathologists were uncertain about breast specimen orientation. Ambiguous marking methods caused orientation errors in half of the cases, while unclear marking directions caused the rest. Most pathologists (85%) and surgeons (75%) believed that coronal plane specimen mammography would help solve the problem. A plastic specimen plate has been developed to anchor breast tissue to a coronal breast scheme as seen in mammography images, providing clear localization information throughout the surgical process. There is a lack of standardization in breast specimen orientation and marking in Hungary. An optimized orientation toolkit is being developed to ensure consistent interpretation of specimen mammograms by surgeons and pathologists.
Open Access: Yes
Nonlinear kinematic impacts on nanofluid flow across rough surface with numerical simulation
Publication Name: Scientific Reports
Publication Date: 2025-12-01
Volume: 15
Issue: 1
Page Range: Unknown
Description:
The current study demonstrates the intricate thermo-solutal transportation features of a nanofluid experiencing non-linear kinematics as it flows across a rough porous stretched interface. Previous work has typically been limited to smooth geometries, narrow parameter ranges, and few physical intuitions. However, this paper extends the analysis to include surface roughness, porosity effect, nonlinear stretching and essential physical phenomena like effect of magnetic field, Brownian motion special case thermophoresis effect and variable suction/injection. The resulting extension does not only reproduce realistic flow cases, but reveals extremely sensitive solution behaviors that have been completely untouched in the literature. Using scaling transformation approach, the governing non-linear partial differential equations (PDEs) for the transport of momentum, energy, and solutal in the transformed independent variables are translated into a set of coupled ordinary differential equations (ODEs). Numerical simulation of the above transport equations with ten dimensionless parameters is done using the MATLAB BVP4C (built in solver) approach, which ensures computational stability and high precision across broad parametric domains. Additionally, using an expanded parameter domain revealed previously unknown solution properties. For instance, as the thermophoretic limitation raised, the species concentration rose by 5% and fell by 12%. Additionally, sensitivity was demonstrated by the velocity profiles shifting by 20% in response to a small variation in the slip parameter. Finding the limits at which qualitatively reactions to system modifications and other non-physical solutions arise from the qualitative responses is notably innovative. Such findings will propel the development of more efficient coatings and temperature control techniques, offering helpful advice to greatly improve transportation effectiveness in actual nanofluid applications.
Open Access: Yes
Comparison of Different Turbulence Models and Wall Treatment Methods for Vehicle Aerodynamics Investigations
Publication Name: Periodica Polytechnica Transportation Engineering
Publication Date: 2024-01-01
Volume: 52
Issue: 1
Page Range: 67-74
Description:
In this paper two different turbulence models and wall treatment methods were investigated with Computational Fluid Dynamics (CFD) method. The used geometry for the research was the Ahmed body. The Ahmed body is a widely used geometry in vehicle aerodynamics investigations. The geometry represents a simplified vehicle, which allows the researchers to make examinations with moderate resources. The simulations were made in Ansys Fluent. The environment of the simulation was built to optimize for maximum 8 GB RAM. The paper examines the difference between the k-ω SST and the k-ε turbulence models in the case of low and high Reynolds number wall treatment methods. This could be useful because the high Reynolds number wall treatment method needs less computational capacity based on that, its required y+ range is between 30 and 300. While in the case of the low Reynolds wall treatment method the required y+ range is below 10, which could increase the cell count. The results from the CFD simulation will be compared to each other and with measured data. The aim of the research is to get information about behaviour of the examined turbulence models in the case of low and high Reynolds number wall treatment methods.
Open Access: Yes
DOI: 10.3311/PPTR.22671
AMERICAN VERSUS DOMESTIC DIGITAL COMPANIES IN THE CHINESE MARKET
Publication Name: Decision Making Applications in Management and Engineering
Publication Date: 2022-10-01
Volume: 5
Issue: 2
Page Range: 120-139
Description:
The digital economy has become an increasingly important part of the world economy. It is vastly concentrated in two economies, namely, the United States and China. The main aim of our study is to investigate Chinese digital companies and government policy enabling the rapid development of the country’s digital economy and the largest American digital companies’ performance in the Chinese market. Our findings show that the largest American digital companies, which are globally active players, usually have a very limited market share in different segments of the Chinese digital economy or have been forced to leave the Chinese market after a short period of operation. In the future, Chinese government policy will continue to ensure the priority role of domestic digital companies in the upgrading and structural transformation of the Chinese economy driven by services, high-tech sectors, and consumption while limiting the role of American digital companies.
Open Access: Yes
MULTI-CRITERIA DECISION ANALYSIS OF CIRCULAR ECONOMY PERFORMANCE IN THE BALTIC STATES: A COMPARATIVE EVALUATION
Publication Name: Journal of Business Economics and Management
Publication Date: 2025-10-10
Volume: 26
Issue: 5
Page Range: 1050-1070
Description:
This study embarks on a comparative evaluation of Circular Economy (CE) performance in the Baltic States (Latvia, Lithuania, and Estonia) using a ro-bust multi-criteria decision-making (MCDM) framework. Drawing on 22 key indicators, the research applies the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to systematically rank the country-level CE implementation across five thematic dimensions: production and consumption, waste management, secondary raw materials, competitiveness and innovation, and global sustainability. The results reveal that Latvia ranks highest, followed by Lithuania and Estonia, underscoring significant differences in waste management efficiency, investment in CE sectors, and material self-sufficiency. The main contribution of this paper lies in the development of a comprehensive, quantitative bench-marking framework that integrates multiple CE indicators and MCDM methods to assess national performance in a data-driven manner. The methodology developed here can serve as a replicable model for CE assessment in other regional or national contexts.
Open Access: Yes
