Search Results (30,076)

Fractional calculus provides powerful tools for modeling nonlocality, dissipative systems, and, when defined in the time representation, provides an interesting memory effect in mathematical physics. In this paper, we review four standard fractional approaches: the Riemann–Liouville, Gerasimov–Caputo, Grünwald–Letnikov, and Riesz formulations. We present their definitions, basic properties, Weyl–Marchaud, and physical interpretations. We also give a brief review of related operators that have been used recently in applications but have received less attention in the physical literature: the fractional Laplacian, conformable derivatives, and the Fractional Action-Like Variational Approach (FALVA) for variational principles with fractional action weights. Our emphasis is on how these operators are, and can be, applied in physical problems rather than on exhaustive coverage of the field. This review is intended as an accessible introduction for physicists working in diverse areas interested in fractional calculus and fractional methods. For deeper technical or domain-specific treatments, readers are encouraged to consult the works in the corresponding fields, for which the bibliography suggests a starting point. Full article

The contemporary healthcare environment is characterized by high stress and emotional burden, contributing to increasing rates of professional burnout among clinicians. Exposure to patient death represents one of the most emotionally taxing experiences in medicine, particularly in obstetrics and gynecology (OB/GYN), where loss of life stands in stark contrast to the life-giving nature of the field. Despite extensive research on burnout in oncology and intensive care, the impact of patient death and death perception on OB/GYN clinicians remains underexplored. Objective: This study aimed to examine the relationships between exposure to patient death, perceptions of death, professional burnout, and professional fulfillment among OB/GYN clinicians. A secondary aim was to explore whether participation in emotional regulation training was associated with these variables. Methods: A cross-sectional study was conducted among 138 OB/GYN clinicians. An author-developed questionnaire was used, comprising scales measuring professional burnout, positive and negative death perception, professional fulfillment, professional development, and a global death-impact index. Statistical analyses included Pearson’s correlation and the Mann–Whitney U test to compare clinicians who had attended emotional regulation training with those who had not. Results: Significant positive correlations were observed between burnout and the death-impact index (r = 0.90, p < 0.001) and between burnout and negative death perception (r = 0.23, p = 0.007). Professional fulfillment strongly correlated with professional development (r = 0.94, p < 0.001) and positively with positive death perception (r = 0.30, p < 0.001). No significant group differences were found regarding emotional regulation training participation. Conclusions: Exposure to patient death in OB/GYN is strongly associated with professional burnout and negative perceptions of death. Conversely, professional fulfillment and development function as factors promoting resilience and meaning. Further research should validate the applied measurement tools and examine the effectiveness of emotional regulation interventions in reducing occupational distress. Full article

Technocracy refers to any political–social–economic system that is governed and managed using purportedly objective scientific and technical principles, and in which ultimate power and authority rests with technical and scientific experts. The concept had its initial origins in the early decades of the Industrial Revolution (with antecedents stretching back to the rationalism of ancient Greece and, later, the Enlightenment in the West). Henri Saint-Simon in early 19th century France was the earliest exponent of a technocratic system which involved overall political and economic government by industrialists. Technocracy was formally coined as a term in the early 20th century in the United States in the context of a specific intellectual movement under the same name which laid out a more detailed system of economic and social management by industrialists and scientists that supposedly would guarantee maximum efficiency in production, consumption and distribution without the self-defeating tendencies of political systems of the time, either democratic or authoritarian. Technocracy is currently used to refer to any policy or governmental arrangement that purportedly emphasizes technical criteria above non-technical values in policy, planning and public decision-making, and which gives significant authority to experts. Singapore is often referred to as a leading example of such an approach. Various controversies have arisen around technocracy, especially its potential incompatibility with democracy and social values that are not easily translated into technical terms. There is also debate about how feasible a genuine technocracy actually is in practice. Full article

Theological empiricism is the view that knowledge of God must ultimately rest on human experience. This puts it in opposition to theologies that rely exclusively on conceptual analysis and biblical revelation, or some combination of the two. Theological empiricism is not new. It has forerunners in the natural theology of the 18th century, and the appeal to feeling and intuition characteristic of some 19th-century theologians. What is new is the concept of ‘experimental theology’ and the suggestion that in seeking to secure an empirical basis for knowledge of God, theology should turn to the methods characteristic of the natural sciences. This paper argues that empiricism in theology is more plausible if it resists this suggestion. It gives special attention to the faculty of imagination in both science and art, and seeks to articulate the ways in which literature, painting, music and architecture can be said to embody empirical knowledge of a broadly theological kind. Full article

Post-translational modifications (phosphorylation and glutathionylation) not only assure protein diversity but are also responsible for the controlling of the biological activity of selected proteins in health and disease. The aim of the study was to monitor the profile of changes in molecular weight of proteins undergoing selected post-translational modifications by measurement of the intensity of phosphorylation and glutathionylation within the pregnancy course and parturition in cows with and without the retention of foetal membranes. The intensity of selected post-translational modifications was measured in bovine placental tissues collected during pregnancy (2nd, 4th, 5th, and 7th month, n = 4 per month) and parturition (not-retained foetal membranes (NRFM, n = 6) and retained foetal membranes (RFM, n = 6). Placental tissues were homogenised and used for the Phosphoprotein Phosphate Estimation Assay Kit and Western blotting analyses with adequate antibodies. The content of phosphorylated proteins was significantly higher (p < 0.05) in the 2nd month as compared to other months, both in the maternal and foetal parts of the placenta. Moreover, no significant differences were observed between NRFM and RFM samples. The results of Western blotting showed the shift in molecular weight and indirect content of phosphorylated selected amino acids. Further research on the role of post-translational modifications in pregnancy and parturition may give new insight into their biochemical regulation. Full article

Olive cultivation constitutes a fundamental Mediterranean rural activity in Greece, as it primarily accounts for the country’s substantial socio-economic development. Although the olive tree is one of the best acclimated species, its overall performance may be significantly impacted by changes in the climate. Thus, by considering the lack of scientific research on the climate suitability evaluation of olive groves over the entire Greek territory, a study between the geomorphological parameter mapping of Greece (altitude, aspect, slope, and terrain roughness) and the respective required atmospheric conditions for the olive crop’s growth (temperature, precipitation, and frost days) was performed. Every parameter is reclassified to translate its value into a score, and the final suitability map is the outcome of the aggregation of all score maps. Individually, the overall suitability for olive cultivation is high in Greece, given its extensive area, resulting in a high score (8–10); geomorphological and climatic conditions (34.44% and 59.40%, respectively); and overall suitability conditions (42.00%) for olive cultivation. Over the identified olive grove areas, the model gives a high score (8–10) for 91.59% of the cases. The model may be characterized by its simplicity, usability, flexibility, and efficiency. The current modelling procedure may serve as a means for identifying suitable areas for the sustainable and productive development of olive cultivation. Full article

Within the field of assisted reproductive technologies (ARTs), embryologists regularly face the critical task of identifying embryos with the highest likelihood of implantation and survival. To help aid and standardize this practice, many embryo selection strategies have been developed to give the best chance of pregnancy success. Over the years, there has been a large increase in experimental studies conducted within this area of research. This increase has allowed for the formation of significant and plausible theories of embryo development, especially in cases where the most prominent factors seem identical. These advancements have both expanded the typical process of traditional treatments and have even paved the way for new techniques. The exact combination of all these relevant factors has not been fully elucidated into a single all-encompassing scheme for embryo decision. Morphological, genetic, and developmental indicators are well-studied individually, but the exact methods that should be prioritized in each scenario may change with respect to an individual patient. Deciding whether factors like age, egg quality, lifestyle choices, or previous medical history should alter methods of embryo ranking can result in conflict, especially in the case where a choice is being made between two similar embryos. This article reviews the conventional methods along with emerging technologies that provide the tools for embryologists to evaluate and rank embryos with high implantation potential (HIP). By showcasing these methods, including their respective benefits and drawbacks, this article provides information to allow clinicians to make effective decisions by integrating multiple approaches to embryo selection. Full article

In this work, we propose a novel Biased Random-Key Genetic Algorithm (BRKGA) to solve the Maximum Flow with Minimum Number of Labels (MF-ML) problem, a challenging NP-Complete variant of the classical Maximum Flow problem defined on graphs in which arcs have both capacities and labels assigned. Labels give a qualitative characterization of each connection, in contexts where a solution that is as homogeneous as possible is sought. The MF-ML problem aims to maximize the flow from a source to a sink on a capacitated network while minimizing the number of distinct arc labels used, a modeling framework with applications such as water purification in distribution systems. Our proposed algorithm encodes solutions as random-key vectors, which are decoded into feasible solutions. The BRKGA demonstrates superior performance when compared to a Skewed Variable Neighborhood Search (VNS) approach previously proposed to solve MF-ML. In particular, on the largest considered graphs, BRKGA-MFML outperformed VNS in 55 out of 81 scenarios, with an average improvement per scenario that reaches 7.18%. Full article

Previous research identified three reasons for valuing nature (i.e., the basis for seeing nature as valuable and important): (1) valuing nature for what it gives to humans (instrumental), (2) valuing nature for its own sake (intrinsic), and (3) valuing nature because of the relationship between people and nature (relational). Of these, relational value-bases have been less studied, especially in non-Western cultures. Using a large sample (n = 2618), with participants from five distinct cultural regions (Japan, Taiwan, Italy, France, USA), the present research tests whether a three-factor framework of environmental value-bases generalizes to other cultures. Our findings demonstrate the configural and metric invariance of the recently validated Environmental Value-Bases Scale, indicating that the latent constructs generalize across sub-samples of the five regions and that the measure can be used to test associations between the value-bases and outcomes across cultures. However, we only found partial scalar invariance, suggesting (a) that caution is needed when comparing scale means between cultures and (b) that such tests are most appropriately performed using latent means. This research further contributes to the growing value-basis literature by comparing the latent means for each value-basis between and within each of the five regions and by demonstrating their associations with place attachment. Full article

The internal architecture of deep-water channels is highly complex. Previous research has primarily emphasized the sedimentary processes governing channel migration, yet the linkage between sediment-source mechanisms and migration patterns—particularly their vertical evolution—remains insufficiently understood. Drawing on 3D seismic data, well logs, and core analyses, this study delineates the channel architecture within the deep-water succession of the Niger Delta Basin. Furthermore, by correlating high-frequency sea-level fluctuations with the formation timing of structural units, we explore how sea-level changes influence the spatial distribution and evolutionary dynamics of submarine fan systems. This study investigated the bottom-up evolution of two channel-lobe systems—the East Channel System (ECS) and West Channel System (WCS) within the stratigraphic succession, identifying two principal channel migration styles: expansive migration and downstream migration. In the ECS, migration was primarily characterized by a combination of downstream and expansive patterns. In contrast, the WCS displayed intermittent downstream migration, accompanied by some irregular migration. Correlation of sea-level variation curves with corresponding core photographs indicates that the ECS developed during a fourth-order sea-level. Its lower lobe and upper channel intervals each correspond to two complete five-stage sea-level cycles. In this system, debris flows and high-density turbidity currents produced stronger lateral erosion and channel migration, giving rise to the expansive migration style. Conversely, the WCS formed during a four-stage sea-level rise, with its lobe and channel sections likewise corresponding to two complete five-stage sea-level cycles. Here, sedimentation dominated by high- and low-density turbidity currents promoted enhanced erosion and migration along the flow direction, resulting in the predominance of downstream migration patterns. The ECS and WCS together constitute a complete three-tiered stratigraphic sequence representing two lobe–channel systems. This configuration deviates to some extent from the conventional understanding of the spatial distribution of debris flows, lobate channels, main channels, and deep-sea mud deposits. Consequently, during intervals of frequent sea-level fluctuation, deep-water sedimentary components within the continental slope region can partially record the signals of fourth- and even fifth-order sea-level variations, facilitated by a stable tectonic framework and favorable sediment preservation conditions. These findings offer valuable insights for reconstructing regional sedimentary processes and interpreting sea-level evolution. Full article

Chromophore domains were proposed in a previous work as the mediators of self-healing of optical properties in dye-doped polymers. A statistical mechanical model based on domains matches all observed self-healing dynamics as a function of dye concentration, temperature and light intensity. This suggests that domains are responsible. However, there is no direct observation of domains, nor has their physical morphology been determined. This work reports the first observation of domains in a self-healing polymer using Resonant Soft X-ray Scattering (RSoXS), which gives a domain size in the range of 39.3 Å to 62.8 Å. This range includes the domain model’s prediction of an average domain size of roughly 30 molecules, which is about 56 Å, if the molecules form a loosely packed ball. X-ray scattering of samples of concentration spanning from neat polymer to the saturation limit of Disperse Orange 11 (DO11) dye in poly (methyl methacrylate) (PMMA) polymer shows domains in the expected size scales, with the mode of the effective scattering width varying little with concentration. However, for constant domain shape, the mode peak would decrease in q with increasing concentration, according to the domain model. This work suggests that the domain shape might change with concentration, which warrants further investigations of domain topology and geometry. The important evidence presented in this work is the direct experimental observation of domains, which is central to self-healing models. Full article

In this study, we used the hydrophobic-polar (HP) two-dimensional square and three-dimensional cubic lattice models for the problem of protein structure prediction (PSP). This kind of lattice reduces computational time and calculations, the conformational space from $9^n$ to $3^{n-2}$ for the 2D square lattice and $5^{n-2}$ for the 3D cubic lattice. Even within this context, it remains challenging for genetic algorithms or other metaheuristics to identify the optimal solutions. The contributions of the paper consist of: (1) implementation of a high-performing novel genetic algorithm (GA); instead of considering only the self-avoiding walk (SAW) conformations approached in other work, we decided to allow any conformation to appear in the population at all stages of the proposed all conformations biomimetic genetic algorithm (ACGA). This increases the probability of achieving good conformations (self avoiding walk ones), with the lowest energy. In addition to classical crossover and mutation operators, (2) we introduced specific translation operators for these two operations. We have proposed and implemented an HP Protein Visualizer tool which offers interpretability, a hybrid approach in that the visualizer gives some insight to the algorithm, that analyse and optimise protein structures HP model. The program resulted based on performed research, provides a molecular modeling tool for studying protein folding using technologies such as Node.js, Express and p5js for 3D rendering, and includes optimization algorithms to simulate protein folding. Full article

Zeolitic imidazolate frameworks (ZIFs) can provide fascinating stereo morphology and tunable metal active sites, which plays an important role in the synthesis of various catalytic materials. However, it is still a problem to make use of these advantages to design efficient hydrogen evolution reaction (HER) catalysts. Herein, we use covalent coordination strategy to synthesize bimetallic Co_xZn_1−x(2-MeIM)₂ precursors with regular dodecahedral structures for providing uniform active sites and stable carbon skeleton. Furthermore, the ratio of Co and Zn atoms was optimized to balance the electron density and give full play to the synergistic catalytic effect. And then, the subsequent high temperature annealing process is used to construct the amorphous carbon layer, which can improve the overall stability of the material. The gas phase phosphating process realizes the transformation from ZIF material to metal phosphide resulting in enhanced hydrogen evolution activity. Finally, the optimized amorphous nitrogen-doped carbon (NC)-coated Zinc-doped cobalt phosphide (Zn_0.17Co_0.83P@NC) requires only 237.60 mV to reach the current density of 10 mA cm⁻² in alkaline medium, which is 223.22 mV lower than that of CoP, and has a stability of up to 18 h. This work provides a reference for the rational design of efficient and stable compound electrocatalysts for alkaline hydrogen evolution based on the bimetallic ZIF as a precursor. Full article

Accurate quality-of-transmission (QoT) estimation prior to lightpath deployment is essential for minimizing design margins in optical networks. Owing to their high precision and strong generalization capabilities, artificial neural networks (ANNs) have emerged as a promising approach for lightpath QoT estimation. However, focusing exclusively on prediction accuracy is inadequate for maximizing global network capacity. Conventional models employing symmetric loss functions apply identical penalties to both overestimation and underestimation errors, thereby precluding controlled bias in predictions and their impact on overall network capacity. This paper investigates the margin configuration for the whole network capacity and proposes a novel QoT estimation method with asymmetric loss functions, which jointly considers the assessment of global network capacity and gives different penalties for overestimation and underestimation. We further present an iterative search algorithm grounded in network capacity considerations to optimize the parameters of these asymmetric loss functions. Simulation results confirm that our ANN-based models facilitate efficient modulation format assignment, leading to corresponding increases in network capacity. Full article

In organic solids, the heterogeneous distribution of organic molecules in the solid state gives rise to novel structure–property relationships. Here, we use transmission electron microscopy to investigate the aggregated structure of organic solid of a typical phosphorescent molecule Ir(ppy)₃ at the atomic scale. Through the identification of heavy Ir atoms in the molecular structure, we reveal the existence of organic crystals, clusters and single molecules in the solids. Through electron energy loss spectroscopy, we explore the vibration modes of molecules and lattices in the solids and possible perturbations by excitons induced by electron beam, which could affect the electroluminescent property of the molecules. Full article