General Structure Research Articles

A General Descriptor for Single-Atom Catalysts with Axial Ligands.

Decoration of an axial coordination ligand (ACL) on the active metal site is a highly effective and versatile strategy to tune activity of single-atom catalysts (SACs). However, the regulation mechanism of ACLs on SACs is still incompletely known. Herein, we investigate diversified combinations of ACL-SACs, including all 3d-5d transition metals and ten prototype ACLs. We identify that ACLs can weaken the adsorption capability of the metal atom (M) by raising the bonding energy levels of the M-O bond while enhancing dispersity of the d orbital of M. Through examination of various local configurations and intrinsic parameters of ACL-SACs, a general structure descriptor σ is constructed to quantify the structure-activity relationship of ACL-SACs which solely based on a few key intrinsic features. Importantly, we also identified the axial ligand descriptor σACL, as a part of σ, which can serve as a potential descriptor to determine the rate-limiting steps (RLS) of ACL-SACs in experiment. And we predicted several ACL-SACs, namely, CrN4-, FeN4-, CoN4-, RuN4-, RhN4-, OsN4-, IrN4- and PtN4-ACLs, that entail markedly higher activities than the benchmark catalysts of Pt and IrO2 for oxygen reduction reaction and oxygen evolution reaction, respectively, thereby supporting that the general descriptor σ can provide a simple and cost-effective method to assess efficient electrocatalysts.

General formalism for symmetrically structured flows according to constructal Law

Flows from point to line or to surface (and vice versa) that obey a set of constraints are necessarily structured (Constructal Law). We can observe this feature in natural systems, in man-made systems, in the economy and in society. Here we develop a formalism for general application in point to line and point to surface symmetrical flow structures with constraints. We show that flow structuring occurs between successive branching levels, and that it is possible to find general structuring rules of the respective flow tree according to the Constructal Law.

Studies on the Trichomes of some Compositae I. General Structure

Seventy two Compositae belonging to 56 genera representing the thirteen tribes of the family have been investigated in this study, Trichomes are recognised broadly into two categories namely the 'vegetative' and the 'floral' ones. It is the former that have been presently taken up for detailed investigations. In all 35 trichome types are found so far in the family. Of these, 15 have been described by previous workers which the present author has also observed in the species under investigation. Another 13 are the newly established types by the author. The remaining 7 represent types which the author has not come across during the present investigations but are described in the literature.The general features of the trichomes in the family are discussed in the light of the present study. The trichomes are shown to exhibit in all four patterns in their structure which provide important evidence in the phylogeny of the trichomes.

The Measured Flow at the Inlet of a Francis Turbine Runner Operating in Speed No-Load Condition

Abstract For Francis turbines, speed-no-load (SNL) represents one of the most detrimental operating conditions, marked by significant pressure and strain fluctuations on the runner. Mitigating these fluctuations necessitates a comprehensive understanding and characterization of the flow phenomena responsible for their generation. This paper presents an experimental investigation of the flow at the inlet of a Francis turbine runner model operating in speed-no-load condition using high-speed stereoscopic and endoscopic particle image velocimetry (PIV). The measurements are made in a radial-azimuthal plane that covers the vaneless space and a large region in the interblade channel. This study marks the first-time measurement of critical flow phenomena at this operating point, performed in the runner. Instantaneous and average velocity fields are analyzed, along with other statistical data. The results not only confirm the stochastic nature of the flow at speed-no-load but also highlight the general structure of the flow observed in other studies. The high velocity fluctuations on the suction side are associated with a backflow extending into the vaneless space and a circulation zone occasionally generated by this backflow. Both phenomena are frequently present, but fluctuate stochastically. Additionally, two other circulation zones intermittently form on the pressure side of the blades. The presence of vortices, smaller than the circulation zones, near the blade's leading edge correlates with the backflow intensity.

Comparative Comparison of the Curriculum of the Master's Degree in Emergency Nursing in Iran and Monash University in Australia

Introduction: Training emergency nurses plays a significant role in caring for critically ill patients. The comparison of emergency nursing curricula in Iran with those in prestigious universities is one of the ways to determine the strengths and weaknesses of each curriculum. This study aims to conduct a comparative analysis of the Master's degree curriculum in emergency nursing in Iran and Monash University in Australia. Methods: The current study is a comparative review that was conducted in 2024. First, Monash University was selected as a top-ranked institution based on the Quacquarelli Symonds rankings of nursing schools worldwide. Afterward, the required information was collected from the Monash University website, the Master of Emergency Nursing program, the curriculum file, and field information. The collected data were compared using the Bereday model, which includes 4 stages: description, interpretation, juxtaposition, and comparison. Results: The Master's program in emergency nursing in Iran and Monash University of Australia showed many similarities in content, general structure, and the role of graduates. However, there were some differences in the procedure of accepting students and educational units, philosophy, mission, and vision. One of the strengths of Iran's curriculum was the presence of general courses, whereas Monash University stood out for the prerequisite of English language proficiency for admission. There were no work experience requirements in either curriculum; nevertheless, a valid bachelor's degree was required. At Monash, there have been significant improvements by using new teaching techniques, such as simulation training. However, regular updates and reviews of the curriculum in Iran remain necessary. Conclusion: The present study can be one of the appropriate guides for policymakers in the field of nursing education in order to improve the quality and development of nurses' skills. It is recommended that policymakers incorporate new and important courses into the curriculum to promote clinical nursing skills.

To the problem of improving technical skills of ski racers

The article examines the ways of optimizing the educational process and improving the management of motor actions in sports training by using different activity conditions (modes, action tasks) and creating functional systems of the technology of progression of sports skills. It has been established that the regimes of alternating exercises with rest are a means of selective action on indicators of general and special work capacity, coordination structure of movements, reaction of the body’s service systems. The effect of alternating exercise regimes with rest "A" and "B" and action tasks "faster thrust", "wider step" on the change of individual indicators of technique, movements, speed, speed endurance of ski racers when overcoming climbs was established. The practical significance of the obtained data is that they allow building models of directed and previously known action not only for the change of the integral indicator of special performance, but also for the parameters of the coordination structure of movements, as well as to determine the athlete's behavior program depending on the topography of the competition. Research results make it possible to create models of lessons that selectively affect various systems of the athletes' body and contribute to more accurate management of the development of special working capacity, the formation of technical skills. The application of these models in the general structure of the development of special capacity for work creates an opportunity to comprehensively influence a person as a complex organized, self-regulating system. Practical use of research results optimizes the process of managing sports training over a longer period of time.

Tuning-free sparse clustering via alternating hard-thresholding

Model-based clustering is a commonly-used technique to partition heterogeneous data into homogeneous groups. When the analysis is to be conducted with a large number of features, analysts face simultaneous challenges in model interpretability, clustering accuracy, and computational efficiency. Several Bayesian and penalization methods have been proposed to select important features for model-based clustering. However, the performance of those methods relies on a careful algorithmic tuning, which can be time-consuming for high-dimensional cases. In this paper, we propose a new sparse clustering method based on alternating hard-thresholding. The new method is conceptually simple and tuning-free. With a user-specified sparsity level, it efficiently detects a set of key features by eliminating a large number of features that are less useful for clustering. Based on the selected key features, one can readily obtain an effective clustering of the original high-dimensional data under a general sparse covariance structure. Under mild conditions, we show that the new method leads to clusters with a misclassification rate consistent to the optimal rate as if the underlying true model were used. The promising performance of the new method is supported by both simulated and real data examples.

Global Experience in the Use of Unmanned Aviation Technologies in Public Administration: a Review

TUnmanned Aerial Systems (UAS), despite their relative novelty, are already an integral component of the general aviation structure, and, based on a number of complex and sophisticated solutions, including those related to artificial intelligence, are part of the spectrum of high technologies. UAS find application not only in the sphere of commerce, but also in the realisation of specific tasks of public administration, such as territory management, healthcare, emergency prevention and elimination, ensuring environmental safety and law and order, nature management. The purpose of the study, the results of which are presented in this publication, is to assess the current state and potential of the use of UAS in these areas based on a review of literature sources on the practice of their application in order to solve the tasks of public administration in different countries of the world. The main conclusion drawn from the analysis and characterising the general scientific novelty of the study is that, despite a significant number of specific examples, the breadth of UAS use range can be characterised as imaginary. The main and the only really significant application is various types of aerial survey in the interests of state control and supervision bodies. In the course of the work, a number of promising directions for the use of UAS have been identified. It is also noted that their wider implementation in the practice of public administration is hindered by the lack and/or imperfection of the relevant legal framework, typical for most legislative systems of the world, and postulates the need to actively address these issues in relation to the classification and certification of UAS, requirements for their operators and software, the procedure and rules of operation, the integration of unmanned aircraft (UAS) into the existing air traffic management system.

Effects of Copper Foam Wall/Obstacles on the Deflagration-to-Detonation Transition

To investigate the process of deflagration-to-detonation transition (DDT) of the copper foam wall in the pulse detonation engine, detonation combustion experiments were carried out using ethylene and oxygen-enriched air (oxygen concentration: 40%) as fuel and oxidant. The effects of copper foam pore size, thickness, installation length, and structure on the flame acceleration were studied experimentally, as were the effects of blockage ratio and mixture equivalence ratio. The results show that among the four pore sizes selected, the 10 PPI case produces the fastest flame development on the porous flat wall. For conditions with successful detonation, the 10 PPI case reduces the DDT distance and time by 34.97 and 42.57%, respectively, compared with the 40 PPI case. Regarding the installation length of copper foam, it is found that copper foam with a large pore size (10 PPI) and a short installation length achieves stable detonation. The general structure of copper foam was also analyzed, including the porous flat wall, porous obstacle, and solid obstacle with the same installation length. These three structures effectively accelerate the initiation of detonation. Particularly, porous obstacles show more pronounced effects on flame acceleration than the commonly used solid obstacles. These results are instructive for optimizing the short-distance ignition ability of pulsed detonation engines.

Momentum space oscillation properties of vortex states collision

A qualitative calculation and discussion of two-vortex-state collisions are given in the scalar ϕ4 model. Three kinds of vortex states—Bessel, general monochromatic, and Laguerre-Gaussian—are considered. It is found that the total final-momentum distribution in the collision of physical vortex states displays general topological structures, which depend on the initial vortex states’ topological charges, which are proportional to the orbital angular momenta. This peculiar matching provides a novel observable, the topological number of momentum distribution, and it may represent a new fascinating research direction in particle physics. We also find that the situation when the angular momenta of the two colliding Laguerre-Gaussian states combine to zero can be recognized by the total final-momentum distribution close to the collision axis. Both features can be used to measure the orbital angular momentum of vortex states. Published by the American Physical Society 2024

ОДНОВИМІРНА ЗГОРТКОВА МОДЕЛЬ НЕЙРОННОЇ МЕРЕЖІ ДЛЯ ОБРОБЛЕННЯ СИГНАЛІВ З АМПЛІТУДНОЮ МОДУЛЯЦІЄЮ БАГАТЬОХ СКЛАДОВИХ

The processing of radio signals using artificial neural networks (ANNs) has great potential for research, which can be explained by the adaptability of ANNs to various transmission conditions and the ability to detect abstract patterns of changes in signal parameters. The article reviews the works of other authors devoted to different ways of using ANNs for processing radio signals. Taking into account the information in the reviewed works, the research task was formed, which consists in developing an optimized ANN model for radio signal processing. Signals with amplitude modulation of many components (AMMC) were chosen to form training samples for ANN. The choice of modulation type is justified by greater energy efficiency compared to other widely used digital modulation types, such as quadrature amplitude modulation. Mathematic basis of AMMC signal generation is described. The process of finding the coordinates of three component 8-AMMC signal constellation is explained, the formation of signals in the time plane based on the found coordinates is explained as well as their discretization and the addition of white noise. An iterative algorithm for generating initial data for ANN based on the described ratios is proposed. The general structure of one-dimensional convolutional neural network is considered. Functions of individual neurons, connections between them, the formation of layers and the convolution operation are described mathematically. On the basis of the previously given ratios, a final display of the network was formed. Specific dimensions and activation functions for layers are selected. The use of convolutional layers is justified by time invariance. Based on the reviewed mathematical models, selected activation functions and dimensions, a neural model was formed. The process of validating the effectiveness of the formed neural model is described, which is based on comparing the symbolic error probabilities of the proposed and reference models at different signal-to-noise ratios. The validation results are presented. The advantages of the obtained model over the previously proposed purely recurrent model and the AMMC reference receiver are explained.

Wall-crossing effects on quiver BPS algebras

BPS states in supersymmetric theories can admit additional algebro-geometric structures in their spectra, described as quiver Yangian algebras. Equivariant fixed points on the quiver variety are interpreted as vectors populating a representation module, and matrix elements for the generators are then defined as Duistermaat-Heckman integrals in the vicinity of these points. The well-known wall-crossing phenomena are that the fixed point spectrum establishes a dependence on the stability (Fayet-Illiopolous) parameters ζ, jumping abruptly across the walls of marginal stability, which divide the ζ-space into a collection of stability chambers — “phases” of the theory. The standard construction of the quiver Yangian algebra relies heavily on the molten crystal model, valid in a sole cyclic chamber where all the ζ-parameters have the same sign. We propose to lift this restriction and investigate the effects of the wall-crossing phenomena on the quiver Yangian algebra and its representations — starting with the example of affine super-Yangian \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Y}}\\left({\\widehat{\\mathfrak{g}\\mathfrak{l}}}_{1\\left|1\\right.}\\right)$$\\end{document}. In addition to the molten crystal construction more general atomic structures appear, in other non-cyclic phases (chambers of the ζ-space). We call them glasses and also divide in a few different classes. For some of the new phases we manage to associate an algebraic structure again as a representation of the same affine Yangian \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Y}}\\left({\\widehat{\\mathfrak{g}\\mathfrak{l}}}_{1\\left|1\\right.}\\right)$$\\end{document}. This observation supports an earlier conjecture that the BPS algebraic structures can be considered as new wall-crossing invariants.

Experience in the Use of Surgical Access to the Distal Part of the Radius in Comminuted Intra-articular Fractures

Introduction. Fractures of the distal radius occupy a leading place in the general structure of limb injuries. In most cases, they are comminuted in nature and require open reduction and fixation. With traditional surgical approaches to the distal radius, there is a risk of injury to the tendons of the muscles of the anterior group of the forearm and the median nerve; in addition, the skin incision lines pass through the projection of the gap of the wrist joint, which leads to the formation of painful scars and difficulty moving in the early postoperative period.The purpose of the work is to evaluate the results of using a new surgical approach to the distal radius for the treatment of comminuted intra-articular fractures.Materials and methods. A retrospective analysis of the results of surgical treatment of 124 patients aged 19 to 78 years with a fracture of the distal radius for the period from 2015 to 2019 was carried out. A patient with a fracture of the distal epimetaphysis of the radius, Fernandez type III, underwent surgery through the proposed approach.Results. Aſter transosseous osteosynthesis with a distraction external fixation device, on the sixth day, open reduction, bone graſting and plate osteosynthesis were performed through the proposed approach. Restoration of congruence of the articular surfaces of the wrist joint has been achieved. In the early postoperative period, movement in the joint is free, discomfort during the rehabilitation program is minimal. Aſter 12 months, movements in the joint are fully realized.Discussion. The new access makes it possible to improve the conditions for operations on the distal part of the radius with its fractures, creates a sufficiently spacious and safe access to the radius, which allows you to preserve the muscular part of the square pronator and does not violate the anatomy of the synovial sheaths of the tendons of the muscles of the anterior forearm group, which is prevention of the development of deficiency of rotational movements of the forearm and contractures of the hand and fingers in early and late postoperative periods.Conclusion. The developed new surgical approach to the distal radius provides optimalvisualization of the fracture andis low-traumatic, which has a positive effect on restoring full range of motionin the wrist jointin the early stages aſter surgery.

Helping Children Achieve Literacy Proficiency: A Case Study

ABSTRACT A single embedded case study was conducted to examine the benefits students experience from participating in the Augustine Literacy Project – Charlotte (ALP) Tutoring Program, specifically regarding the positive outcomes in students’ reading proficiency development. A survey was administered to 135 tutors, followed by person-to-person semi-structured interviews with 12 tutors. Additionally, scores on pre- and post-assessments were analyzed to determine students’ progress in their literacy skills. A comparison of mean scores at the beginning and end of the school year showed a statistically significant difference for all the reading components assessed in the DIBELS and the ALP assessments. Findings from this study suggest that ALP-Charlotte administrators and tutors have worked effectively to help struggling readers achieve higher levels of literacy proficiency. The strengths identified in the ALP program are the tutoring approach, the tutor training program, the relationship between tutors and students, student access to individualized instruction, and the program’s general structure. Likewise, recommendations for program improvement were also identified, which included offering ongoing training throughout the school year, diversifying the tutor population, strengthening the relationship between tutors and other tutors, parents, and teachers, and dealing with distracting factors and student behavior issues.

Credit default swap pricing with counterparty risk in a reduced form model with Hawkes process

Credit default swap pricing with counterparty risk in a reduced form model with Hawkes process

An analytic description of electron thermalization in kilonovae ejecta

ABSTRACT A simple analytic description is provided of the rate of energy deposition by β-decay electrons in the homologously expanding radioactive plasma ejected in neutron star mergers, valid for a wide range of ejecta parameters – initial entropy, electron fraction {s0, Ye}, and scaled (time-independent) density ρt3. The formulae are derived using detailed numerical calculations following the time-dependent composition and β-decay emission spectra (including the effect of delayed deposition). The deposition efficiency depends mainly on ρt3 and only weakly on {s0, Ye}. The time te at which the ratio between the rates of electron energy deposition and energy production drops to 1 − e−1, is given by $t_e=t_{0e}\Big (\frac{\rho t^3}{0.5(\rho t^3)_0}\Big)^a$, where $(\rho t^3)_0=\frac{0.05\, {\rm M}_{\odot }}{4\pi (0.2c)^3}$, t0e(s0, Ye) ≈ 17 d, and 0.4 ≤ a(s0, Ye) ≤ 0.5. The fractional uncertainty in te due to nuclear physics uncertainties is $\approx 10~{{\ \rm per\ cent}}$. The result a ≤ 0.5 reflects the fact that the characteristic β-decay electron energies do not decrease with time (largely due to ‘inverted decay chains’ in which a slowly decaying isotope decays to a rapidly decaying isotope with higher end-point energy). We provide an analytic approximation for the time-dependent electron energy deposition rate, reproducing the numerical results to better than 50 per cent (typically $\lt 30~{{\ \rm per\ cent}}$, well within the energy production rate uncertainty due to nuclear physics uncertainties) over a 3–4 orders-of-magnitude deposition rate decrease with time. Our results may be easily incorporated in calculations of kilonovae light curves (with general density and composition structures), eliminating the need to numerically follow the time-dependent electron spectra. Identifying te, e.g. in the bolometric light curve, will constrain the ejecta density distribution.

Quadratic American Strangle Options in Light of Two-Sided Optimal Stopping Problems

The aim of this paper is to examine some American-style financial instruments that lead to two-sided optimal hitting problems. We pay particular attention to derivatives that are similar to strangle options but have a quadratic payoff function. We consider these derivatives in light of much more general payoff structures under certain conditions which guarantee that the optimal strategy is an exit from a strip. Closed-form formulas for the optimal boundaries and the fair price are derived when the contract has no maturity constraints. We obtain the form of the optimal boundaries under the finite maturity horizon and approximate them by maximizing the financial utility of the derivative holder. The Crank–Nicolson finite difference method is applied to the pricing problem. The importance of these novel financial instruments is supported by several features that are very useful for financial practice. They combine the characteristics of the power options and the ordinary American straddles. Quadratic strangles are suitable for investors who need to hedge strongly, far from the strike positions. In contrast, the near-the-money positions offer a relatively lower payoff than the ordinary straddles. Note that the usual options pay exactly the overprice; no more, no less. In addition, the quadratic strangles allow investors to hedge the positions below and above the strike together. This is very useful in periods of high volatility when large market movements are expected but their direction is unknown.

Networked Leadership Roles for School Leaders' Work with Schools' Digitalization

School leaders are responsible for creating the right conditions for schools and, through dialogue, understanding schools' needs and prerequisites, distributing resources, and following up on the schools' development. School leaders are also important for supporting schools in realizing a top-down policy. One example of such policy is the digitalization policy aimed at implementing digital technologies in teaching, where strong school leaders is necessary. Thus, leadership is a crucial ingredient for a good digitalization process in schools. However, there is little written about school leaders' practice. Further, school leaders' practice may contain more networked leadership despite the fact that they often assumed a top-down leadership role, which would be especially clear when viewed through a networked learning perspective. Further, different countries have different school systems where the school leaders may be referred to by different names in their roles for supporting the schools.A common area in need of support is the digitalization of schools. Students may not get the skills they need in the future as challenges to ensure the advancement is enacted continue to broaden. Thus, it may be interesting to delve deeper into the structures of countries that may differ in general structure for school systems. In conjunction with a networked collaboration between the University of Brazil and Mid Sweden University, connections between the school systems in both countries will be made in this paper to distinguish parts of their leadership strategy for the digitalization of schools. Leadership within schools is closely connected to the pedagogical implementation of technologies. In one dimension of school leadership related to digitalization, there exists a notable aspect known as the networked dimension, which is intricately linked to assessment policies and roles associated with ICT. Given the assumption for the networked dimension, this paper is written for two primary purposes. The first purpose is to investigate the networked leadership dimension according to various leadership roles for school leaders' digitalization work. The second purpose is to prepare a comparative study of the school systems of Brazil and Sweden by reviewing literature that analyses these regions.Thus, in this short paper, we assume that school leaders' practice when compared across two countries different in size from a networked leadership perspective may comprise a research gap, indicating the relevancy of a literature review investigation of this gap.

On the existence and uniqueness results for fuzzy fractional boundary value problem involving Caputo iractional derivative

In this paper, we investigate the existence and uniqueness of solutions for fuzzy boundary value problems involving fuzzy Caputo fractional derivatives of order q 2 (2, 3). As a preliminary step, we construct a generic structure of the solution associated with our proposed model by utilizing the Green’s function. We establish the existence of a unique solution of the proposed model paired with the given initial conditions by using Banach fixed point theorem. At last, as application, an illustrative example is given to show the applicability of our theoritical results.

On the gauge invariance of the higher-derivative Yang–Mills–Chern–Simons action

In this work, we study the perturbative generation of the gauge invariant effective action for the non-Abelian gauge field in a (2+1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(2+1)$$\\end{document}-dimensional spacetime. We present a detailed analysis of the two, three and four-point functions in order to determine the non-Abelian Chern–Simons terms (parity odd) and Yang–Mills terms (parity even). Moreover, these terms are supplemented by the higher-derivative corrections which resulted in the Alekseev–Arbuzov–Baikov effective action (parity even) plus the higher-derivative (HD) corrections to the Chern–Simons terms (parity odd). In order to highlight some features about the perturbative generation of the effective action, we present a discussion based on the dimensional analysis, which allows us to establish the general structure of the permissible terms to guarantee the gauge invariance of the higher-derivative parts.