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1.
J Environ Sci (China) ; 148: 27-37, 2025 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-39095163

RESUMO

Naphthenic acids, NAs, are a major contaminant of concern and a focus of much research around remediation of oil sand process affected waters, OSPW. Using activated carbon adsorbents are an attractive option given their low cost of fabrication and implementation. A deeper evaluation of the effect NA structural differences have on uptake affinity is warranted. Here we provide an in-depth exploration of NA adsorption including many more model NA species than have been assessed previously with evaluation of adsorption kinetics and isotherms at the relevant alkaline pH of OSPW using several different carbon adsorbents with pH buffering to simulate the behaviour of real OSPW. Uptake for the NA varied considerably regardless of the activated carbon used, ranging from 350 mg/g to near zero highlighting recalcitrant NAs. The equilibrium data was explored to identify structural features of these species and key physiochemical properties that influence adsorption. We found that certain NA will be resistant to adsorption when hydrophobic adsorbents are used. Adsorption isotherm modelling helped explore interactions occurring at the interface between NA and adsorbent surfaces. We identified the importance of NA hydrophobicity for activated carbon uptake. Evidence is also presented that indicates favorable hydrogen bonding between certain NA and surface site hydroxyl groups, demonstrating the importance of adsorbent surface functionality for NA uptake. This research highlights the challenges associated with removing NAs from OSPW through adsorption and also identifies how adsorbent surface chemistry modification can be used to increase the removal efficiency of recalcitrant NA species.


Assuntos
Ácidos Carboxílicos , Poluentes Químicos da Água , Adsorção , Ácidos Carboxílicos/química , Poluentes Químicos da Água/química , Carvão Vegetal/química , Modelos Químicos , Cinética , Concentração de Íons de Hidrogênio
2.
Interv Pain Med ; 3(1): 100401, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39239499

RESUMO

Objective: Lumbar medial branch denervation is commonly used to treat chronic facetogenic low back pain. Controversy exists regarding risk to adjacent neural structures. The objectives of this cadaveric study were to: (1) dissect, digitize, and model in 3D the branches of the first (L1) to fifth (L5) lumbar dorsal rami located near the junction of the transverse process and lateral neck of the superior articular process; and (2) quantify the minimal distance between the lateral/intermediate and medial branches at the anterior quarter and midpoint of the lateral neck of the superior articular process. Design: Eighteen formalin-embalmed specimens were dissected, digitized and modeled in 3D. The high-fidelity 3D models were used to compare branching patterns and quantify the mean minimal distance between the lateral/intermediate and medial branches of the lumbar dorsal ramus at the anterior quarter and midpoint of the lateral neck of the superior articular process. A Two-way ANOVA was performed to determine if difference of mean distances was significant. Results: There was variability in the branching pattern of the lumbar dorsal rami. In 46 cases (51.1%) the lumbar dorsal ramus divided into 2 branches, in 41 cases (45.6%) into 3, and in 3 cases (3.3%) 4. The mean minimal distance between the lateral/intermediate and medial branches was significantly greater at the midpoint (3.2 ± 2.5 mm) than the anterior quarter (1.2 ± 1.8 mm) of the lateral neck of superior articular process. Conclusion: Minimal distance measurements between the branches of the lumbar dorsal rami at the anterior quarter and midpoint of the lateral neck of the superior articular process were computed. When placing the distal end of the needle tip at the anterior quarter of the lateral neck of the superior articular process, the smaller mean minimal distance between the branches suggests there is a greater risk for inadvertent denervation of the lateral/intermediate branches. Further anatomical and clinical investigations are required.

3.
Sci Rep ; 14(1): 20554, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39232039

RESUMO

This study presents the findings of a comprehensive geotechnical and seismic site investigation conducted at Otuasega Town located in Bayelsa State within the Niger Delta region of Nigeria. Subsurface exploration involved advancing 10 boreholes to 30 m depth using hollow stem auger drilling. Continuous disturbed and undisturbed soil sampling was performed at 1.5 m intervals for detailed geotechnical testing. Laboratory tests on the recovered soil samples established the index properties, classification, densities and consistency limits of the stratified deposits. The subsurface profile comprised alternating layers of clay, silt and sand typical of deltaic sediments, with the clay fractions exhibiting medium to high plasticity. Shear wave velocity (Vs) profiling using Multichannel Analysis of Surface Waves (WASW) techniques categorised the site predominantly as Site Class C and D based on international standards. The Standard Penetration Test (SPT) N-values ranged from 5 to 10, indicating soft normally consolidated clay conditions typical of the Niger Delta region. Predictive empirical models developed from the field and lab data showed strong correlations for estimating key geotechnical parameters such as SPT blow count, Vs and liquefaction resistance. Ground response analyses using the Vs and SPT data indicated significant site amplification potential, with peak ground accelerations up to 1.5 times the bedrock motion. Liquefaction analysis based on the empirical SPT-based methods revealed a high potential for liquefaction in the sandy layers, especially under strong earthquake shaking. The study characterized the complex sedimentology and provided baseline information for seismic microzonation and site-specific ground response analyses to advance understanding of geohazards in this delta environment.

4.
J Physiol ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39235952

RESUMO

Throughout our lifetime the heart executes cycles of contraction and relaxation to meet the body's ever-changing metabolic needs. This vital function is continuously regulated by the autonomic nervous system. Cardiovascular dysfunction and autonomic dysregulation are also closely associated; however, the degrees of cause and effect are not always readily discernible. Thus, to better understand cardiovascular disorders, it is crucial to develop model systems that can be used to study the neurocardiac interaction in healthy and diseased states. Human pluripotent stem cell (hiPSC) technology offers a unique human-based modelling system that allows for studies of disease effects on the cells of the heart and autonomic neurons as well as of their interaction. In this review, we summarize current understanding of the embryonic development of the autonomic, cardiac and neurocardiac systems, their regulation, as well as recent progress of in vitro modelling systems based on hiPSCs. We further discuss the advantages and limitations of hiPSC-based models in neurocardiac research.

5.
ISME J ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39236233

RESUMO

Soil microbial communities host a large number of microbial species that support important ecological functions such as biogeochemical cycling and plant nutrition. The extent and stability of these functions are affected by inter-species interactions among soil microorganisms, yet the different mechanisms underpinning microbial interactions in the soil are not fully understood. Here, we study the extent of nutrient-based interactions among two model, plant-supporting soil microorganisms, the fungi Serendipita indica, and the bacteria Bacillus subtilis. We found that S. indica is unable to grow with nitrate - a common nitrogen source in the soil - but this inability could be rescued, and growth restored in the presence of B. subtilis. We demonstrate that this effect is due to B. subtilis utilising nitrate and releasing ammonia, which can be used by S. indica. We refer to this type of mechanism as ammonia mediated nitrogen sharing (N-sharing). Using a mathematical model, we demonstrated that the pH dependent equilibrium between ammonia (NH3) and ammonium (NH+4) results in an inherent cellular leakiness, and that reduced amonnium uptake or assimilation rates could result in higher levels of leaked ammonia. In line with this model, a mutant B. subtilis - devoid of ammonia uptake - showed higher S. indica growth support in nitrate media. These findings highlight that ammonia based N-sharing can be a previously under-appreciated mechanism underpinning interaction among soil microorganisms and could be influenced by microbial or abiotic alteration of pH in microenvironments.

6.
J Mol Biol ; 436(17): 168704, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39237192

RESUMO

Knowledge of protein-ligand complexes is essential for efficient drug design. Virtual docking can bring important information on putative complexes but it is still far from being simultaneously fast and accurate. Receptors are flexible and adapt to the incoming small molecules while docking is highly sensitive to small conformational deviations. Conformation ensemble is providing a mean to simulate protein flexibility. However, modeling multiple protein structures for many targets is seldom connected to ligand screening in an efficient and straightforward manner. @TOME-3 is an updated version of our former pipeline @TOME-2, in which protein structure modeling is now directly interfaced with flexible ligand docking. Sequence-sequence profile comparisons identify suitable PDB templates for structure modeling and ligands from these templates are used to deduce binding sites to be screened. In addition, bound ligand can be used as pharmacophoric restraint during the virtual docking. The latter is performed by PLANTS while the docking poses are analysed through multiple chemoinformatics functions. This unique combination of tools allows rapid and efficient ligand docking on multiple receptor conformations in parallel. @TOME-3 is freely available on the web at https://atome.cbs.cnrs.fr.


Assuntos
Simulação de Acoplamento Molecular , Conformação Proteica , Proteínas , Ligantes , Proteínas/química , Proteínas/metabolismo , Sítios de Ligação , Ligação Proteica , Software , Desenho de Fármacos , Modelos Moleculares
7.
Artigo em Inglês | MEDLINE | ID: mdl-39237457

RESUMO

Obesity and underweight are a growing health problem worldwide and a challenge for clinicians concerning antithrombotic therapy, due to the associated risks of thrombosis and/or bleeding. This clinical consensus statement updates a previous one published in 2018, by reviewing the most recent evidence on antithrombotic drugs based on body size categories according to the World Health Organization classification. The document focuses mostly on individuals at the extremes of body weight, i.e. underweight and moderate-to-morbid obesity who require antithrombotic drugs, according to current guidelines, for the treatment or prevention of cardiovascular diseases or venous thromboembolism. Managing antithrombotic therapy or thromboprophylaxis in these individuals is challenging, due to profound changes in body composition, metabolism and organ function, altered drug pharmacokinetics and pharmacodynamics, as well as weak or no evidence from clinical trials. The document also includes artificial intelligence simulations derived from in silico pharmacokinetic/pharmacodynamic models, which can mimic the pharmacokinetic changes and help identify optimal regimens of antithrombotic drugs for severely underweight or severely obese individuals. Further, bariatric surgery in morbidly obese subjects is frequently performed worldwide. Bariatric surgery causes specific and additional changes in metabolism and gastrointestinal anatomy, depending on the type of the procedure, which can also impact the pharmacokinetics of antithrombotic drugs and their management. Based on existing literature, the document provides consensus statements on optimising antithrombotic drug management for underweight and all classes of obese patients, while highlighting the current gaps in knowledge in these complex clinical settings, which require personalized medicine and precision pharmacology.

8.
Int J Artif Organs ; : 3913988241268067, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39238170

RESUMO

Medical advancements, particularly in ventricular assist devices (VADs), have notably advanced heart failure (HF) treatment, improving patient outcomes. However, challenges such as adverse events (strokes, bleeding and thrombosis) persist. Computational fluid dynamics (CFD) simulations are instrumental in understanding VAD flow dynamics and the associated flow-induced adverse events resulting from non-physiological flow conditions in the VAD.This study aims to validate critical CFD simulation parameters for accurate VAD simulations interacting with the cardiovascular system, building upon the groundwork laid by Hahne et al. A bidirectional coupling technique was used to model dynamic (pulsatile) flow conditions of the VAD CFD interacting with the cardiovascular system. Mesh size, time steps and simulation method (URANS, LES) were systematically varied to evaluate their impact on the dynamic pump performance (dynamic H-Q curve) of the HeartMate 3, aiming to find the optimal simulation configuration for accurately reproduce the dynamic H-Q curve. The new Overlapping Ratio (OR) method was developed and applied to quantify dynamic H-Q curves.In particular, mesh and time step sizes were found to have the greatest influence on the calculated pump performance. Therefore, small time steps and large mesh sizes are recommended to obtain accurate dynamic H-Q curves. On the other hand, the influence of the simulation method was not significant in this study. This study contributes to advancing VAD simulations, ultimately enhancing clinical efficacy and patient outcomes.

9.
Artigo em Inglês | MEDLINE | ID: mdl-39256215

RESUMO

AIM: The recently introduced Long-Axial-Field-of-View (LAFOV) PET-CT scanners allow for the first-time whole-body dynamic- and parametric imaging. Primary aim of this study was the comparison of direct and indirect Patlak imaging as well as the comparison of different time frames for Patlak calculation with the LAFOV PET-CT in oncological patients. Secondary aims of the study were lesion detectability and comparison of Patlak analysis with a two-tissue-compartment model (2TCM). METHODOLOGY: 50 oncological patients with 346 tumor lesions were enrolled in the study. All patients underwent [18F]FDG PET/CT (skull to upper thigh). Here, the Image-Derived-Input-Function) (IDIF) from the descending aorta was used as the exclusive input function. Four sets of images have been reviewed visually and evaluated quantitatively using the target-to-background (TBR) and contrast-to-noise ratio (CNR): short-time (30 min)-direct (STD) Patlak Ki, short-time (30 min)-indirect (STI) Patlak Ki, long-time (59.25 min)-indirect (LTI) Patlak Ki, and 50-60 min SUV (sumSUV). VOI-based 2TCM was used for the evaluation of tumor lesions and normal tissues and compared with the results of Patlak model. RESULTS: No significant differences were observed between the four approaches regarding the number of tumor lesions. However, we found three discordant results: a true positive liver lesion in all Patlak Ki images, a false positive liver lesion delineated only in LTI Ki which was a hemangioma according to MRI and a true negative example in a patient with an atelectasis next to a lung tumor. STD, STI and LTI Ki images had superior TBR in comparison with sumSUV images (2.9-, 3.3- and 4.3-fold higher respectively). TBR of LTI Ki were significantly higher than STD Ki. VOI-based k3 showed a 21-fold higher TBR than sumSUV. Parameters of different models vary in their differential capability between tumor lesions and normal tissue like Patlak Ki which was better in normal lung and 2TCM k3 which was better in normal liver. 2TCM Ki revealed the highest correlation (r = 0.95) with the LTI Patlak Ki in tumor lesions group and demonstrated the highest correlation with the STD Patlak Ki in all tissues group and normal tissues group (r = 0.93 and r = 0.74 respectively). CONCLUSIONS: Dynamic [18F]-FDG with the new LAFOV PET/CT scanner produces Patlak Ki images with better lesion contrast than SUV images, but does not increase the lesion detection rate. The time window used for Patlak imaging plays a more important role than the direct or indirect method. A combination of different models, like Patlak and 2TCM may be helpful in parametric imaging to obtain the best TBR in the whole body in future.

10.
New Phytol ; 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39256946

RESUMO

Local adaptation to contrasting environmental conditions along environmental gradients is a widespread phenomenon in plant populations, yet we lack a mechanistic understanding of how individual agents of selection contribute to this evolutionary process. Here, we developed a novel evolutionary functional-structural plant (E-FSP) model that recreates local adaptation of virtual plants along an environmental gradient. First, we validate the model by testing if it can reproduce two elevational ecotypes of Dianthus carthusianorum occurring in the Swiss Alps. Second, we use the E-FSP model to disentangle the relative contribution of abiotic (temperature) and biotic (competition and pollination) selection pressures to elevational adaptation in D. carthusianorum. Our results suggest that elevational adaptation in D. carthusianorum is predominantly driven by the abiotic environment. The model reproduced the qualitative differences between the elevational ecotypes in two phenological (germination and flowering time) and one morphological trait (stalk height), as well as qualitative differences in four performance variables that emerge from G × E interactions (flowering time, number of stalks, rosette area and seed production). Our approach shows how E-FSP models incorporating physiological, ecological and evolutionary mechanisms can be used in combination with experiments to examine hypotheses about patterns of adaptation observed in the field.

11.
J R Soc Interface ; 21(218): 20240301, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39257281

RESUMO

Comparing COVID-19 response strategies across nations is a key step in preparing for future pandemics. Conventional comparisons, which rank individual non-pharmaceutical intervention (NPI) effects, are limited by: (i) a focus on epidemiological outcomes; (ii) NPIs typically being applied as packages of interventions; and (iii) different political, economic and social conditions among nations. Here, we develop a coupled epidemiological-behavioural-macroeconomic model that can transfer NPI effects from a reference nation to a focal nation. This approach quantifies epidemiological, behavioural and economic outcomes while accounting for both packaged NPIs and differing conditions among nations. As a first proof of concept, we take Germany as our focal nation during Spring 2020, and New Zealand and Switzerland as reference nations with contrasting NPI strategies. Our results suggest that, while New Zealand's more aggressive strategy would have yielded modest epidemiological gains in Germany, it would have resulted in substantially higher economic costs while dramatically reducing social contacts. In contrast, Switzerland's more lenient strategy would have prolonged the first wave in Germany, but would also have increased relative costs. More generally, these findings indicate that our approach can provide novel, multifaceted insights on the efficacy of pandemic response strategies, and therefore merits further exploration and development.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Humanos , Nova Zelândia/epidemiologia , Suíça/epidemiologia , Alemanha/epidemiologia , Pandemias/prevenção & controle
12.
Sci Total Environ ; 953: 175921, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39226969

RESUMO

Experience from earlier nuclear accidents has clearly shown the need for maintaining and developing appropriate modelling capabilities. Dealing with complex issues such as human exposure following a nuclear accident necessitates the implementation of a set of interconnected models such as FDMT. FDMT is an integrated module within the two main European decision support systems for radiological emergency preparedness, ARGOS and JRODOS, to simulate the transfer of radionuclides along terrestrial food chains and to predict their activity concentrations in foodstuffs. In order to make the module more fit-for-purpose, FDMT has been implemented in a new modelling platform (ECOLEGO) which provides a high degree of flexibility with regard to conducting developmental work. This paper presents improvements in FDMT further through either the incorporation of new models or further elaboration of existing ones, as well as updates in default parameters. Models have also been made more fit-for-purpose through consideration of regional-specific parameters. Specific improvements include modelling developments related to dry deposition, radioactive particle weathering, radiocaesium transfer influenced by soil characteristics and, for a region-specific case, animal uptake. In addition, the paper presents new pathways and parameters (and updated values) to be considered for making FDMT more adapted for Norwegian conditions. Overall, the improvements made in the present work should significantly reduce the uncertainties associated with the outputs of the FDMT models.

13.
Sci Total Environ ; 953: 176000, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39233080

RESUMO

Αirborne microplastics (MPs) are considered an important exposure hazard to humans, especially in the indoor environment. Deposition and clearance of MPs in the human respiratory tract (HRT) was investigated using the ExDoM2 dosimetry model, modified to incorporate the deposition and clearance of MPs fibers. Fiber deposition was calculated via the fiber equivalent aerodynamic diameter determined using their properties such as size, density and dynamic shape factor. Scenario simulations were performed for elongated particles of cylindrical (base) diameters 1 µm and 10 µm and aspect ratios (ratio of fiber length to base diameter) 3, 10 and 100. Modelling results showed that the highest fiber deposition occurred in the extra-thoracic region due to large particles (fiber cylindrical diameter dp > 0.1 µm), whereas particle length (via the aspect ratio) had an influence mainly on smaller base-diameter fibers (dp < 0.1 µm) that deposited predominantly in the alveolar region. The ExDoM2 dosimetry model was also used to calculate fiber deposition in the HRT using experimental data for microplastic fiber and fragment concentrations in different microenvironments. The highest deposited number dose (220 fibers) after a 24-hour exposure was calculated in the microenvironment (bus) that had the highest fiber concentration (17.3 ± 2.4 fibers/m3). After clearance, the majority (66.4 %) of the average deposited fiber mass was transferred from the respiratory tract to the esophagus via mucociliary clearance, 32.6 % was retained in the respiratory tract, 1 % passed into the blood, and a very small amount (0.0004 %) was transferred to the lymph nodes.

14.
J Sci Med Sport ; 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-39242326

RESUMO

OBJECTIVES: The aim of this study was to quantify changes in peak bending moments at the distal tibia, peak patellofemoral joint contact forces and peak Achilles tendon forces during a high-intensity run to fatigue at middle-distance speed. DESIGN: Observational study. METHODS: 16 high-level runners (7 female) ran on a treadmill at the final speed achieved during a preceding maximum oxygen uptake test until failure (~3 min). Three-dimensional kinetics and kinematics were used to derive and compare tibial bending moments, patellofemoral joint contact forces and Achilles tendon forces at the start, 33 %, 67 % and the end of the run. RESULTS: Average running speed was 5.7 (0.4) m·s-1. There was a decrease in peak tibial bending moments (-6.8 %, p = 0.004) from the start to the end of the run, driven by a decrease in peak bending moments due to muscular forces (-6.5 %, p = 0.001), whilst there was no difference in peak bending moments due to joint reaction forces. There was an increase in peak patellofemoral joint forces (+8.9 %, p = 0.026) from the start to the end of the run, but a decrease in peak Achilles tendon forces (-9.1 %, p < 0.001). CONCLUSIONS: Running at a fixed, high-intensity speed to failure led to reduced tibial bending moments and Achilles tendon forces, and increased patellofemoral joint forces. Thus, the altered neuromechanics of high-intensity running to fatigue may increase patellofemoral joint injury risk, but may not be a mechanism for tibial or Achilles tendon overuse injury development.

15.
Pest Manag Sci ; 2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39243155

RESUMO

BACKGROUND: Wash-off of plant protection products from crops is represented in current European Union (EU) surface water models and future EU soil models by a coefficient that estimates its contribution to soil loadings following rainfall. Replacing the default coefficient with experimental data requires a harmonized protocol and this research forms part of the development of such a protocol. Following a successful test of the proposed protocol on a single crop across eight laboratories, a range of crops were tested in a single laboratory to assess the impact of crop type on the results. RESULTS: Six crops (wheat, rice, oil seed rape, cabbage, potato and French bean) were chosen, encompassing both hydrophobic and hydrophilic leaf surfaces. Tebuconazole (Folicur EW 250) was sprayed onto plants at a rate equivalent to 100 g ai ha-1 and subjected to a 1-h simulated rainfall event at an intensity of 20 mm h-1. Measured residues before and after rainfall were compared to calculate the percentage wash-off. The extent of wash-off was 66.4% with a 95% confidence interval of ±18.5% and the results were clustered according to leaf wettability, with lower wash-off in hydrophobic crops than in hydrophilic crops. CONCLUSION: Wash-off of this unoptimized formulation was similar across the crops, despite the use of crops with both hydrophobic and hydrophilic leaf surfaces. There is potential, therefore, to rationalize the number of crops used in future studies by selecting a small number of hydrophilic and/or hydrophobic crops to obtain a robust estimation of the extent of wash-off for use in environmental fate models. © 2024 Society of Chemical Industry.

16.
J Environ Radioact ; 280: 107526, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39243485

RESUMO

The prevalence of isotopes of radioxenon in the atmosphere poses a problem for the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The atmospheric radioxenon background has accumulated due to emissions from civil nuclear facilities and as a result, the IMS frequently detects isotopes that might be considered a signal of a nuclear explosion. The UK National Data Centre (NDC) at the Atomic Weapons Establishment (AWE) analyses all data from the IMS radionuclide network and through a new 'event analysis' pipeline, works to determine the source of each detection of interest. The pipeline consists of sample screening, sample association and source reconstruction methods. There are various methods to determine which detections are worthy of further analysis, such as activity concentration magnitude, number of isotopes detected, isotopic activity ratios or consecutive detections. Once the detections have been identified, atmospheric transport and dispersion modelling (ATDM) simulations can be used to identify and characterise the source. Not all sources are known to the Treaty-verification community so work to identify new emitters and their impact on the IMS is critical to the international effort to monitor for nuclear explosions. This work presents a study of the phenomenon of consecutive 133Xe detections (here referred to as 'plumes'), which are frequently identified on the IMS. We consider the likelihood of a plume from various radionuclide release scenarios and conduct an analysis of a database of IMS measurement data, using the outputs of the automatic Radionuclide (RN) and Event Analysis Pipelines.

17.
J Biomech ; 176: 112303, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39243494

RESUMO

An athlete's posture has a significant impact on aerodynamic drag. Although aerodynamic drag in different sports has been studied extensively, most studies have analysed only a limited number of positions, and no generalized methods for optimization are available. In this work, we present a methodology to perform athlete posture optimization with respect to aerodynamic drag reduction. The method combines the virtual skeleton methodology to adjust the athlete's posture, CFD simulations to evaluate the drag for a given posture, and efficient global optimization to find the optimum position. We demonstrate the method by optimizing the time trial position for a cyclist. The cyclist position was parameterized with 6 design parameters, and the optimization required 41 CFD simulations to converge. The optimal posture yielded a reduction in drag of 17 % compared to the initial posture (disregarding bicycle drag). The method has potential to make posture optimization more accessible across a wide range of sports, and lead to insight into the aerodynamic influence of posture in general.

18.
J Theor Biol ; : 111913, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39243882

RESUMO

In this study, we examine the effects of connectivity on the total catch of a fishery consisting of two fishing sites when the fish population is a predator of a larger prey-predator system. To this end, we analyse a prey-predator fish community model in a two-site environment and compute catch at Maximum Sustainable Yield (MSY). We exhibit some emergence phenomenon: the total catch can be greater than the sum of the catch at two isolated sites due to connectivity. This result is obtained when the two sites are heterogeneous. We show that the increase in capture at MSY is maximal for a certain value of the carrying capacity of the second site, all other parameters remaining constant, including the carrying capacity of the first site. A stronger phenomenon can also be observed: even if none of the sites is viable for fishing, the entire system can be viable. We then study the effects of the heterogeneity of the sites and illustrate our results through simulations. It is shown that the excess yield at MSY can become very significant when the characteristics of the prey and predator in terms of potential growth are opposite at each site.

19.
Sci Total Environ ; : 176134, 2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39250970

RESUMO

Climate change affects plant species, especially those with restricted ecology and distribution. Centaurium erythraea is a flowering plant species in the Gentianaceae family, native to Europe, with its centre of diversity in the Mediterranean and western Asia. Of the 11 infraspecific taxa distinct from C. erythraea, only two are common in Europe: C. erythraea subsp. erythraea (widespread nominal subspecies) and C. erythraea subsp. majus (mainly distributed in the western Mediterranean region). Freshly collected samples of 36 plants from 11 localities across Lower Silesia (Central Europe) were utilised for taxonomic and genetic analysis. The barcode sequences of chloroplast DNA region matK were used for molecular analysis. Data deposited in GenBank was also used. Five haplotypes were identified among the analysed specimens. Species Distribution Modelling (SDM) techniques were applied to predict the current and future (short- and long-term projections) potential distribution of C. erythraea subsp. majus and to identify the most influential climatic factors. Despite the typical Mediterranean distribution, the presence of C. erythraea subsp. majus outside its natural range in SW Poland has been confirmed by morphological and genetic studies. The mean monthly precipitation of the wettest quarter and the mean daily temperatures of the warmest quarter were identified as the key climatic factors. Short-term scenarios suggest that C. erythraea subsp. majus will maintain most of its current suitable habitats and potentially expand into the lowlands of Central Europe. However, long-term projections indicate a potential reduction in its currently suitable areas, especially in the southern parts of its range, with a possible expansion into north-western Europe. The results of these studies provide clear evidence of the impact of ongoing climate change on species range changes. These findings suggest that climate change may create new opportunities for Mediterranean species to spread to new regions, using C. erythraea subsp. majus as an example.

20.
BMC Public Health ; 24(1): 2456, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39251930

RESUMO

BACKGROUND: The benefits of exclusive breastfeeding (EBF) have been universally documented, with evidence of positive impacts on a child's optimal growth, development, and survival. However, EBF practices in Nepal have fluctuated and declined over the last 25 years. In addition to the individual factors of mothers and infants, EBF practices are affected by multiple community-level factors. Understanding these factors is essential for designing breastfeeding promotion programs to improve child nutritional status in Nepal. This study investigated the individual- and community-level determinants of EBF practices among young infants aged 0-5 months in Nepal. METHOD: We used the dataset from the Nepal Demographic and Health Survey 2022. Information on EBF in the past 24 h was available for 540 infants aged 0-5 months. A multilevel mixed-effect logistic regression was used to identify individual- and community-level factors associated with EBF among infants aged 0-5 months in Nepal. RESULTS: The 24-hour prevalence of EBF among infants aged 0-5 months was 57.46% (95% confidence interval (CI): 52.18, 62.57). The infant's age was inversely associated with EBF prevalence at the individual level. Compared with infants aged < 1 month, infants aged three months (adjusted odds ratio (AOR): 0.14, 95% CI: 0.05, 0.40), four months (AOR: 0.11, 95% CI: 0.04, 0.28), and five months (AOR: 0.07, 95% CI: 0.03, 0.20) were less likely to receive EBF. At the community level, community-level variables such as ≥ 4 ANC visits coverage, maternal employment status, and poverty level were generated by aggregating the individual characteristics in a cluster and were categorized using quartiles into low ("< 25%"), moderate (25-75%), and high (≥ 75%). Mothers from communities with moderate ≥ 4 ANC visits (AOR: 3.30, 95% CI: 1.65, 6.57) and high ≥ 4 ANC visits (AOR: 2.70, 95% CI: 1.40, 5.22) coverage had higher odds of EBF practices than did those from communities with low ≥ 4 ANC visits coverage. Similarly, communities with moderate (AOR: 2.67, 95% CI: 1.34, 5.30) and high (AOR: 2.34, 95% CI: 1.10, 4.99) levels of maternal employment status and moderate levels of poverty (AOR: 2.20, 95% CI: 1.13, 4.28) were associated with a higher likelihood of EBF practices. Subnational level variation was evident, with infants in Lumbini province having lower odds of EBF (AOR: 0.32, 95% CI: 0.13, 0.77) relative to Koshi province. Approximately 9% of the variation in EBF practices was observed among mothers while mapping across clusters in this study. CONCLUSION: Various individual- and community-level factors influence the uptake of EBF in Nepal, underscoring the need to improve the approaches and strategies of EBF programs. This study highlighted the significant association of community-level factors (≥ 4 ANC visits coverage, poverty level, and maternal employment status) with EBF among infants under 6 months. It revealed approximately 9% variability in EBF across clusters. Future efforts to promote EBF should focus on older infants and communities with low poverty levels and low coverage of recommended ≥ 4 ANC visits. Furthermore, context-specific adaptation of such efforts might be required considering the variation observed between the communities in the present study.


Assuntos
Aleitamento Materno , Análise Multinível , Humanos , Nepal , Aleitamento Materno/estatística & dados numéricos , Lactente , Feminino , Recém-Nascido , Masculino , Adulto , Adulto Jovem , Inquéritos Epidemiológicos , Adolescente , Mães/estatística & dados numéricos , Mães/psicologia , Fatores Socioeconômicos
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