Search Results (48)

Vitamin D has been shown to influence growth in both fetuses and piglets. Pigs housed indoors rely solely on their feed as a source of vitamin D since they are never exposed to natural sunlight. UVB light is effective in improving the vitamin D status in sows and piglets housed indoors. This study aimed to investigate an innovative method for UVB lighting to enhance the vitamin D status of gestating sows to a level that could positively impact the growth of both fetuses and suckling piglets. A total of 386 sows were included at the time of insemination. Of these, 197 were exposed to a daily dose of UVB light, and 189 sows served as a control group. Both sows and piglets in the UVB group had significantly higher vitamin D levels in serum samples at the time of farrowing than sows and piglets from the control group. No statistically significant differences in litter weight or the number of liveborn or stillborn piglets were observed between groups. UVB light installed in an electronic sow feeder was successful, but, unfortunately, the lamp used in the study was unable to induce the production of vitamin D to the desired level in the sows. Further studies are needed to investigate the effect of higher doses of UVB light. Full article

This article designs and validates a P-Q-based shunt active power filter (SAPF) to mitigate voltage harmonics in EERSA’s 13.2 kV feeder 1500080T03. A CYMDIST feeder model, calibrated with field measurements, reveals worst-case voltage THD up to 9.48% due to legacy high-pressure sodium (HPS) street lighting. Co-simulation with a MATLAB/Simulink R2024b, controller guides the sizing of a 150 kVA SAPF at Substation 8. Simulations reduce peak THD at a representative node from 9.48% to 1.51%; replacing HPS with LEDs further improves efficiency while lowering distortion. The retrofit complies with IEEE Std 519-2022, enhances supply reliability, and yields an internal rate of return above 17%, indicating a technically and financially attractive solution for Latin American distribution networks. Full article

This work presents a methodology for designing deployable reflector antennas that combine origami structures and the Fresnel zone plate lens to obtain a compact antenna structure. In particular, Miura and Yoshimura’s origami patterns have been considered for the design of the Fresnel reflector mirror and the conical horn antenna feeder, respectively. A set of memory-form alloy (MFA) actuators have been used to deploy the antenna. The MFA actuators are activated by a direct current aimed at increasing the temperature and activating the memorized shape. The combination of these techniques provides light, inexpensive, and very compact antennas, particularly suitable for satellite applications. A numerical and experimental assessment campaign has been carried out on antenna prototypes operating in the $K_u$ band at 15 GHz. The obtained experimental results are quite promising. Full article

Monkey beetles (Hopliini, Scarabaeoidea) are a species-rich group of flower-visiting insects that are specialized to feed on floral tissue, pollen and/or nectar. We studied ten South African species, examining morphological features associated with their specific feeding preferences. This is the first attempt in a limited number of beetle species to comparatively investigate both the mouthparts and the alimentary tract in relation to ingested food. Using light microscopy, we found cutting edges on the mandibles and galea teeth in flower tissue-feeding species. Pollen feeders have numerous bristles on the maxillae and a prominent mola on the mandibles that are likely used for gathering and grinding pollen. The elongate heads and mouthparts of the nectar feeders are considered an adaptation that enable these species to mop up nectar while probing flowers. Using µCT imaging and reconstructions of the entire alimentary tract, our morphometric results suggest that food preferences are not related to total relative gut length, although the ratio of foregut to body length was greater in pollen- and nectar-feeding monkey beetles than in floral tissue-feeders. The midgut of females tends to be longer relative to body size compared to males. Our work serves as a basis for generating hypotheses for future research that includes gut morphology in flower-visiting insects. Full article

Small-scale poultry farms often lack access to advanced monitoring tools and rely heavily on manual observation, which is time-consuming, inconsistent, and insufficient for precise flock management. Feeding and drinking behaviors are critical, as they serve as early indicators of health and environmental issues. With global poultry production expanding, raising over 70 billion hens annually, there is an urgent need for intelligent, low-cost systems that can continuously and accurately monitor bird behavior in resource-limited farm settings. This paper presents the development of a computer vision-based chicken behavior monitoring system, specifically designed for small barn environments where at most 10–15 chickens are housed at any time. The developed system consists of an object detection model, created on top of the YOLOv8 model, trained with an imagery dataset of laying hen, feeder, and waterer objects. Although chickens are visually indistinguishable, the system processes each detection per frame using bounding boxes and movement-based approximation identification rather than continuous identity tracking. The approach simplifies the tracking process without losing valuable behavior insights. Over 700 frames were annotated manually for high-quality labeled data, with different lighting, hen positions, and interaction angles with dispensers. The images were annotated in YOLO format and used for training the detection model for 100 epochs, resulting in a model having an average mean average precision (mAP@0.5) metric value of 91.5% and a detection accuracy of over 92%. The proposed system offers an efficient, low-cost solution for monitoring chicken feeding and drinking behaviors in small-scale farms, supporting improved management and early health detection. Full article

This study presents an innovative methodology to optimize the operation of distribution transformers through the estimation of hourly load curves, aimed at minimizing technical losses due to oversizing, particularly in systems lacking advanced metering infrastructure. The proposed approach combines clustering techniques, K-Means with DTW, to identify representative daily consumption patterns and a supervised model based on LightGBM to estimate hourly load curves for unmetered transformers, using customer characteristics as input. These estimated curves are integrated into a process that calculates technical losses, both no-load and load losses, for different transformer sizes, selecting the optimal rating that minimizes losses without compromising demand. Empirical validation showed accuracy levels of 95.6%, 95.29%, and 98.14% at an individual transformer, feeder, and a complete electrical system with 16,864 transformers, respectively. The application of the methodology to a real distribution system revealed a potential annual energy savings of 3004 MWh, equivalent to an estimated economic reduction of 150,238 USD. Full article

Social genetic effects (SGEs) refer to how the genotypes of other individuals impact an individual’s phenotype within a population. These effects significantly influence the feeding behavior and production performance in pigs, though their mechanisms are not well understood. This study examined two pig groups with extreme SGE values for residual feed intake (RFI), analyzing their feeding behavior and the molecular mechanisms involved using transcriptomics and proteomics analysis of liver and ileum tissues. Pigs with higher SGE values exhibited distinct feeding patterns, spending more time at the feeder but making fewer visits. They consumed less overall feed but had a higher intake per visit. Differentially expressed genes and proteins were identified in the liver and ileum and were associated with processes such as mitochondrial functions, oxidative phosphorylation, and cholesterol metabolism. Integrated analysis supported these findings. Combined transcriptome and proteome analysis identified potential key genes that were associated with processes including mitochondrial processes, oxidative phosphorylation, fat digestion and absorption, and cholesterol metabolism. The results showed that pigs with differing SGE values display different feeding behaviors and utilize distinct molecular pathways affecting RFI. These findings offer valuable insights into how SGEs influence feed efficiency and shed light on the fundamental mechanisms underlying it. Full article

Leaky feeders provide seamless and uniform signal coverage in confined spaces like tunnels, mines, and buildings. Their easy scalability and integration with modern systems, like Multiple Input Multiple Output (MIMO), make them ideal for environments requiring reliable and consistent connectivity. However, using optical fiber as a radiating cable has never been investigated before. This may seem infeasible at first sight. However, our experimental study shows otherwise. We measured light leaking from a bent optical fiber transmitter. We also derived closed-form formulas to describe the amount of leakage energy and found that this energy exponentially varies with the square of the curvature radius. This allows us to design an Optical Leaky Feeder (OLF) transmission system for the first time. Then, we analytically show that a slotted optical fiber can be used as a MIMO receiver. The proposed system can ensure reliable, high-quality signal distribution even in challenging environments like tunnels, industrial settings, and dense urban areas. Full article

Most research on bicycling and public transportation integration centers around the developed world and inter-modal bicycle–train travel. Similarly, existing research into the factors influencing bicycling to public transport focuses solely on one aspect of the issue, such as physical infrastructure, social environment, user or individual characteristics, etc. On the other hand, interventions to promote bicycling are less likely to be successful when carried out together since there can be multiple levels of barriers and enablers to bicycling. Hence, this study addresses this gap and utilizes a socio-ecological model as a theoretical foundation to understand the potential of using bicycles as a feeder for bus services by analyzing the barriers and enablers. Data were collected through a face-to-face questionnaire survey conducted in public spaces, including bus stops in Riyadh, Saudi Arabia. Two binary logistics models were developed using Statistical Package for the Social Sciences (SPSS) to analyze the key factors influencing bicycle use as a feeder mode to public buses. The findings reveal that individual socio-demographic factors, reported barriers, and enablers are essential in explaining the users’ likelihood of bicycle use in accessing public buses. The barriers model indicates that existing bicycle parking facilities, bicycle theft and safety issues, bus reliability, and distance to bus stops play an essential role. Effective shading, dedicated bicycle tracks, appropriate lighting, and vital public services are explanatory for the enablers model. The findings offer valuable insights and policy recommendations to improve bicycling infrastructure and promote comprehensive accessibility to public transportation. Full article

The welfare of hens in cage-free systems is closely linked to their behaviors, such as feeding, drinking, pecking, perching, bathing, preening, and foraging. To monitor these behaviors, we developed and evaluated deep learning models based on YOLO (You Only Look Once), an advanced object detection technology known for its high accuracy, speed, and compact size. Three YOLO-based models—YOLOv5s_BH, YOLOv5x_BH, and YOLOv7_BH—were created to track and classify the behaviors of laying hens in cage-free environments. A dataset comprising 1500 training images, 500 validation images, and 50 test images was used to train and validate the models. The models successfully detected poultry behaviors in test images with bounding boxes and objectness scores ranging from 0 to 1. Among the models, YOLOv5s_BH demonstrated superior performance, achieving a precision of 78.1%, surpassing YOLOv5x_BH and YOLOv7_BH by 1.9% and 2.2%, respectively. It also achieved a recall of 71.7%, outperforming YOLOv5x_BH and YOLOv7_BH by 1.9% and 2.8%, respectively. Additionally, YOLOv5s_BH recorded a mean average precision (mAP) of 74.6%, exceeding YOLOv5x_BH by 2.6% and YOLOv7_BH by 9%. While all models demonstrated high detection precision, their performance was influenced by factors such as stocking density, varying light conditions, and obstructions from equipment like drinking lines, perches, and feeders. This study highlights the potential for the automated monitoring of poultry behaviors in cage-free systems, offering valuable insights for producers. Full article

In this paper, we propose a new modified planar Kelvin–Stuart model. We demonstrate some modules for investigating the dynamics of the proposed model. This will be included as an integral part of a planned, much more general Web-based application for scientific computing. Investigations in light of Melnikov’s approach are considered. Some simulations and applications are also presented. The proposed new modifications of planar Kelvin–Stuart models contain many free parameters (the coefficients $g_i,i=1,2,\dots ,N$), which makes them attractive for use in engineering applications such as the antenna feeder technique (a possible generating and simulating of antenna factors) and the theory of approximations (a possible good approximation of a given electrical stage). The probabilistic control of the perturbations is discussed. Full article

The application of arresters is critical for the safe operation of electric grids against lightning. Arresters limit the consequences of lightning-induced over-voltages. However, surge arrester protection in electric grids is challenging due to the intrinsic complexities of distribution grids, including overhead lines and power components such as transformers. In this paper, an optimal arrester placement technique is developed by proposing a multi-objective function that includes technical, safety and risk, and economic indices. However, an effective placement model demands a comprehensive and accurate modeling of an electric grid’s components. In this light, appropriate models of a grid’s components including an arrester, the earth, an oil-immersed transformer, overhead lines, and lightning-induced voltage are developed. To achieve accurate models, high-frequency transient mathematical models are developed for the grid’s components. Notably, to have an accurate model of the arrester, which critically impacts the performance of the arrester placement technique, a new arrester model is developed and evaluated based on real technical data from manufacturers such as Pars, Tridelta, and Siemens. Then, the proposed model is compared with the IEEE, Fernandez, and Pinceti models. The arrester model is incorporated in an optimization problem considering the performance of the over-voltage protection and the risk, technical, and economic indices, and it is solved using the particle swarm optimization (PSO) and Monte Carlo (MC) techniques. To validate the proposed arrester model and the placement technique, real data from the Chopoghloo feeder in Bahar, Hamedan, Iran, are simulated. The feeder is expanded over three different geographical areas, including rural, agricultural plain, and mountainous areas. Full article

In the context of global trade and environmental concerns, this research focuses on examining the influence of the principal dimensions of a container feeder vessel whose propulsion has been modified to operate with green methanol. Methanol emerges as a sustainable marine fuel, reducing emissions and dependence on fossil fuels. The study comprehensively examines the structural challenges posed by container ships, with a particular focus on torsional stresses and hydroelasticity effects. A significant novelty of this study is the inclusion of a comparative structural analysis evaluating how changes in the vessel’s main dimensions impact its structural response. This analysis sheds some light on crucial insights into the effects of structural modifications required for accommodating these changes, ensuring the structural strength of these vessels. The research also underscores the impact of permanent and transient springing and whipping phenomena on fatigue damage. The study’s significance lies in its role in the ongoing transition to sustainable maritime transportation, as it not only examines structural challenges but also provides solutions for achieving an optimal structural configuration in this new era of environmental responsibility. Full article

In this paper we demonstrate some specialized modules for investigating the dynamics of differential models, an integral part of a planned much more general Web-based application for scientific computing. As “corrections” in the Lienard differential system is presented a class of orthogonal polynomials (also known as “shell polynomials”). We will note that some specifics of the amplitudes of these polynomials open up the possibility of modeling signals from the field of antenna-feeder techniques. Algorithms and modules have been consistently used for: automatic generation of a theorem on the number and type of limit cycles (in the light of Melnikov’s considerations); study of the Hamiltonian of the system and “level curves”; for the study of catastrophic surfaces (in the light of Zeeman’s considerations), etc. Similar studies have been carried out for associated polynomials. Numerical examples, illustrating our results using CAS MATHEMATICA are given. Full article

We aimed to investigate whether molecular clues from the extracellular matrix (ECM) can induce oral epithelial differentiation of pluripotent stem cells. Mouse embryonic stem cells (ESC) of the feeder-independent cell line E14 were used as a model for pluripotent stem cells. They were first grown in 2D on various matrices in media containing vitamin C and without leukemia inhibitory factor (LIF). Matrices investigated were gelatin, laminin, and extracellular matrices (ECM) synthesized by primary normal oral fibroblasts and keratinocytes in culture. Differentiation into epithelial lineages was assessed by light microscopy, immunocytochemistry, and flow cytometry for cytokeratins and stem cell markers. ESC grown in 2D on various matrices were afterwards grown in 3D organotypic cultures with or without oral fibroblasts in the collagen matrix and examined histologically and by immunohistochemistry for epithelial (keratin pairs 1/10 and 4/13 to distinguish epidermal from oral epithelia and keratins 8,18,19 to phenotype simple epithelia) and mesenchymal (vimentin) phenotypes. ECM synthesized by either oral fibroblasts or keratinocytes was able to induce, in 2D cultures, the expression of cytokeratins of the stratified epithelial phenotype. When grown in 3D, all ESC developed into two morphologically distinct cell populations on collagen gels: (i) epithelial-like cells organized in islands with occasional cyst- or duct-like structures and (ii) spindle-shaped cells suggestive of mesenchymal differentiation. The 3D culture on oral fibroblast-populated collagen matrices was necessary for further differentiation into oral epithelia. Only ESC initially grown on 2D keratinocyte or fibroblast-synthesized matrices reached full epithelial maturation. In conclusion, ESC can generate oral epithelia under matrix instruction. Full article