Variety Of Theoretical Models Research Articles

Contemporary Assessment of Energy Degeneracy in Orbital Mixing with Tetravalent f-Block Compounds.

The f block is a comparatively understudied group of elements that find applications in many areas. Continued development of technologies involving the lanthanides (Ln) and actinides (An) requires a better fundamental understanding of their chemistry. Specifically, characterizing the electronic structure of the f elements presents a significant challenge due to the spatially core-like but energetically valence-like nature of the f orbitals. This duality led f-block scientists to hypothesize for decades that f-block chemistry is dominated by ionic metal-ligand interactions with little covalency because canonical covalent interactions require both spatial orbital overlap and orbital energy degeneracy. Recent studies on An compounds have suggested that An ions can engage in appreciable orbital mixing between An 5f and ligand orbitals, which was attributed to "energy-degeneracy-driven covalency". This model of bonding has since been a topic of debate because different computational methods have yielded results that support and refute the energy-degeneracy-driven covalency model. In this Viewpoint, literatures concerning the metal- and ligand-edge X-ray absorption near-edge structure (XANES) of five tetravalent f-block systems─MO2 (M = Ln, An), LnF4, MCl62-, and [Ln(NP(pip)3)4]─are compiled and discussed to explore metal-ligand bonding in f-block compounds through experimental metrics. Based on spectral assignments from a variety of theoretical models, covalency is seen to decrease from CeO2 and PrO2 to TbO2 through weaker ligand-to-metal charge-transfer (LMCT) interactions, while these LMCT interactions are not observed in the trivalent Ln sesquixodes until Yb. In comparison, while XANES characterization of AnO2 compounds is scarce, computational modeling of available X-ray absorption spectra suggests that covalency among AnO2 reaches a maximum between Am and Cm. Moreover, a decrease in covalency is observed upon changing ligands while maintaining an isostructural coordination environment from CeO2 to CeF4. These results could allude to the importance of orbital energy degeneracy in f-block bonding, but there are a variety of data gaps and conflicting results from different modeling techniques that need to be addressed before broad conclusions can be drawn.

Electrical resistivity and magnetoresistance of Sr3Fe2+xMo1–xO9–3x/2 (x = 0.45, 0.60, and 1.00) prepared by the solid-state reaction

In this paper, we focus on understanding the behavior of the temperature dependence of electrical resistivity (ρ) and magnetoresistance (MR) in Sr3Fe2+xMo1–xO9–3x/2 perovskites with x = 0.45, 0.60, and 1.00. Three polycrystalline materials were synthesized using conventional solid-state reaction techniques. Rietveld analysis of room-temperature X-ray diffraction data reveals that all three compositions crystallize in tetragonal symmetry; where x = 0.45 and 0.60 undergo an I4/mcm space group, while x = 1.00 adopts a P4/mmm space group. Electrical resistivity measurements carried out at magnetic fields (0 and 1 T) reveal the presence of a transition from the ferromagnetic phase to the paramagnetic phase in the vicinity of the TMI. The metal-insulator transition temperature (TMI) decreases with increasing Fe content and rises slightly with changing magnetic field from 0 to 1 T. The magnetoresistance (MR) of the SrFeO3–δ sample (x = 1.00) has a large value of about 63.6 %, indicating that it can be exploited for certain devices. A variety of theoretical models are used to study the behavior of electrical resistivity in various temperature ranges, showing excellent agreement with experimental results.

Measuring academic resilience of socioeconomically disadvantaged students in Taiwan 2011-2017: Two-part latent class growth modeling based on IRT scores

Academic resilience is a critical topic that has been around for decades and contains a variety of theoretical models and research approaches. In this current study, we adopted the developmental view of resilience. We combined the person-focused (classification and trajectory) and variable-focused (regression) methods to analyze the longitudinal data of 744 students from the TDCYP 2011-2017. We conducted item response theory (IRT) models and a latent class growth modeling framework. First, we measured each person’s latent trait level by IRT and simultaneously identified the classes by positive outcome (academic self-concept) and risk factors. Eventually, to explain the class membership and growth factors by adding covariates. The finding of this study as follows, (1) the four-class model was selected, and they are the competent group (17%), the resilient group (34%), the vulnerable group (31%), and the maladaptive group (18%). (2) The developmental hypothesis of academic resilience was not confirmed because the slope factors of academic self-concept and two groups of risk factors showed no significance. (3) Moreover, we found gender, mental health (illness), and teacher support play critical roles in this study, and they could explain the growth trends and even the membership classifying. The family support and poverty factors were lack of influence might due to the data properties. Importantly, this study can advise educators that it is worth further studying and practicing that school-based context on how to support a student, especially the socioeconomically disadvantaged. Keywords: Academic resilience, socioeconomically disadvantaged, latent class growth modeling, longitudinal IRT schools, Taiwan Database of Children and Youth in Poverty (TDCYP)

Introduction to the special section on suicide and crisis management in clinical practice: Theoretical and practical integration.

Clinical Impact Statement Question: How can knowledge from various theoretical models and clinical settings advance the practical application and scientific study for the assessment and management of crisis behavior? Findings: Clinical applications and the scientific study of standardized methods of crisis and suicide management can be advanced through a variety of theoretical models and within multiple clinical settings. Meaning: Innovation and creativity in the practical application and scientific investigation of standardized methods of suicide and crisis management can best be improved through theoretical frameworks that allow for the systematic testing of hypotheses in support of psychology as a cumulative science. Next Steps: The contributions to this special section demonstrate the use of theoretical models to further the scientific study of evidence-based methods in crisis management. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Assessment tools for reflection in healthcare learners: A scoping review

Reflection has been integrated in many healthcare educations programs to achieve deeper learning and improve professional practice. A variety of evaluation tools are used to assess reflection, but few guides are available to inform educators in their choice of a relevant evaluation tool. The aim of this paper is to identify all existing evaluation tools published along with their strengths and weaknesses. A review strategy retrieved tools available in Medline, PsychInfo, CINALH and Eric databases. The procedures outlined by Munn and colleagues were used to synthetize the information. Additionally, the reflection dimensions assessed in each tool (when sufficient information was available) were analyzed deductively, using thematic analysis according to the Killion and Todnem framework. Subthemes were identified inductively. Forty-five papers were identified, reporting on 34 different tools. The tools were based on a variety of theoretical models. Some had evidence of adequate validity and fidelity. Eleven components of reflection were identified across tools. No tool encompassed all components, but most tools included between three and five components. Context surrounding evaluation should be carefully considered when choosing an evaluation tool for reflection. There is a need for further research to validate the psychometric properties of reflection evaluation tools.

Muonium-Antimuonium Conversion

The MACS experiment performed at PSI in the 1990s provided an yet unchallenged upper bound on the probability for a spontaneous conversion of the muonium atom, { M=}({\mu^+e^-})M=(μ+e−), into its antiatom, antimuonium {\overline{{M}} = }({\mu^-e^+})M¯=(μ−e+). It comprises the culmination of a series of measurements at various accelerator laboratories worldwide. The experimental limits on the process have provided input and steering for the further development of a variety of theoretical models beyond the standard theory, in particular for models which address lepton number violating processes and matter-antimatter oscillations. Several models beyond the standard theory could be strongly disfavored. There is interest in a new measurement and improved sensitivity could be reached by exploiting the time evolution of the conversion process, e.g., at intense pulsed muonium sources.

Molecular dynamics investigation of the stopping power of warm dense hydrogen for electrons.

A variety of theoretical models have been proposed to calculate the stopping power of charged particles in matter, which is a fundamental issue in many fields. However, the approximation adopted in these theories will be challenged under warm dense matter conditions. Molecular dynamics (MD) simulation is a good way to validate the effectiveness of these models. We investigate the stopping power of warm dense hydrogen for electrons with projectile energies ranging from 400-10000eV by means of an electron force field (eFF) method, which can effectively avoid the Coulomb catastrophe in conventional MD calculations. It is found that the stopping power of warm dense hydrogen decreases with increasing temperature of the sample at those high projectile velocities. This phenomenon could be explained by the effect of electronic structure dominated by bound electrons, which is further explicated by a modified random phase approximation (RPA) model based on local density approximation proper to inhomogeneous media. Most of the models extensively accepted by the plasma community, e.g., Landau-Spitzer model, Brown-Preston-Singleton model and RPA model, cannot well address the effect caused by bound electrons so that their predictions of stopping power contradict our result. Therefore, the eFF simulations of this paper reveals the important role played by the bound electrons on stopping power in warm dense plasmas.

Chapter 2 Galactic Gamma-ray Sources * *Supported by Key Research and Development Project (2018YFA0404204, 2016YFA0400804), the National Natural Science Foundation of China (11905043, 11803011, 12173018, 12121003, 11773014, 11633007, U1931204, U1731136), the Original Innovation Program of the Chinese Academy of Sciences (E085021002), Guangdong Major Project of Basic and Applied Basic Research (2019B030302001) and science research grant from the China Manned Space

In the γ-ray sky, the highest fluxes come from Galactic sources: supernova remnants (SNRs), pulsars and pulsar wind nebulae, star forming regions, binaries and micro-quasars, giant molecular clouds, Galactic center, and the large extended area around the Galactic plane. The radiation mechanisms of γ-ray emission and the physics of the emitting particles, such as the origin, acceleration, and propagation, are of very high astrophysical significance. A variety of theoretical models have been suggested for the relevant physics, and emission with energies E≥1014 eV are expected to be crucial in testing them. In particular, this energy band is a direct window to test at which maximum energy a particle can be accelerated in the Galactic sources and whether the most probable source candidates such as Galactic center and SNRs are “PeVatrons”. Designed aiming at the very high energy (VHE, >100 GeV) observation, LHAASO will be a very powerful instrument in these astrophysical studies. Over the past decade, great advances have been made in the VHE γ-ray astronomy. More than 170 VHE γ-ray sources have been observed, and among them, 42 Galactic sources fall in the LHAASO field-of-view. With a sensitivity of 10 milli-Crab, LHAASO can not only provide accurate spectra for the known γ-ray sources, but also search for new TeV-PeV γ-ray sources. In the following sub-sections, the observation of all the Galactic sources with LHAASO will be discussed in details.

A limit equilibrium model for the reinforced face stability analysis of a shallow tunnel in cohesive-frictional soils

Although a variety of theoretical models have been developed to assess the stability of reinforced tunnel faces, the failure mechanisms in these models are inconsistent with the experimental results. This study establishes a 3D model for the stability analysis of a reinforced tunnel face based on the limit equilibrium method and strength reduction technique. This model considers the horizontal soil arching effect and has a reasonable failure mechanism that is composed of two parts: a truncated elliptical cylinder (upper part) and a wedge bound by a log-spiral-shaped slip surface (lower part). The tension failure of the bolts and shear failure of the grout-soil interface are considered in the calculation of the supporting force of the face bolts. For the sake of verification, the results are compared with those from numerical method and typical limit equilibrium methods. The comparisons show that the results obtained by the proposed model agree well with the numerical simulation results, and the average relative difference and absolute difference are 4.89% and 0.10, respectively.Moreover, when the bolt length is shorter than the optimum length, the safety factor and failure mechanism increase with increasing length; when the bolt length exceeds the optimum length, the safety factor remains constant, while the failure mechanism decreases and then remains unchanged. In addition, the applicability of the proposed model for a circular tunnel face is demonstrated by comparing the results of the proposed model with those of previous studies. At the end of this work, design nomograms are presented to allow the proposed model to be used by engineers.

Sensitivity to leptonic CP violation at Hyper-Kamiokande

Hyper-Kamiokande is a next generation water Clierenkov detector, an order of magnitude larger than Super-Kamiokande. capable of large and diverse physics studies. Among these, it will study long baseline oscillation physics with great detail, thanks not only to a larger volume and higher detection efficiency, but also to an improved accelerator and near detector system at J-PARC. We study the effect of a new systematic error model 011 the overall sensitivity of the experiment to the neutrino oscillation parameters, with particular care for the CP violating phase. A variety of theoretical models will benefit from a precise measurement of δ CP, which Hyper-Kamiokande has the capability of constraining, with good precision. The accuracy of the measurement, however, is dictated by the systematic uncertainties and hence it is essential to assess the impact of the new error model 011 the sensitivity.

Psychological models in sport psychology: A preliminary investigation

Applied psychology is characterised by a variety of theoretical models, informing distinct approaches to classification, explanation, and intervention in service-delivery. Such theoretical or psychological models include behavioural, biological, cognitive, humanistic, psychodynamic, and social paradigms, with exposure to these models and attitude formation occurring within the structured university-based stage of sport psychology development. It is, therefore, important for the sport psychological domain to investigate developing attitudes, given these models inform subsequent professional practice and decision making. Accordingly, the present study explored the attitudes of Stage-1 sport psychology students through a modified form of the Maudsley Attitude Questionnaire (34 males, M age = 24.71 years, SD = 7.23 and 42 females, M age = 24.76 years, SD = 6.20). The questionnaire was designed to assess attitudes across eight psychological models (e.g. biological, cognitive) and four sport psychology issues (pre-performance anxiety, a lack of confidence, depression, and eating disorders). Analyses of variance demonstrated significant main, model, and interaction effects. No one psychological model was endorsed by all respondents, with model endorsement varying significantly as a function of the issue presented. Principal Axis Factoring revealed a large contribution attributable to cognitive–behavioural and ‘eclectic’ (mixed elements of social constructionism, biological, and psychodynamic) models. In contrast, the spiritual model represented low levels of participant endorsement and application. Investigation of Stage-1 students can promote an evidence-based understanding on currently developing attitudes and inform the development of sport psychology education, supervision of training routes, and subsequent professional delivery.

A Review of Theoretical and Experimental Research on Various Autofrettage Processes

Autofrettage is a metal forming technique widely incorporated for strengthening the thick-walled cylindrical and spherical pressure vessels. The technique is based on the principle of initially subjecting the cylindrical or spherical vessel to partial plastic deformation and then unloading it; as a result of which compressive residual stresses are set up. On the basis of the type of the forming load, autofrettage can be classified into hydraulic, swage, explosive, thermal, and rotational. Considerable research studies have been carried out on autofrettage with a variety of theoretical models and experimental methods. This paper presents an extensive review of various types of autofrettage processes. A wide range of theoretical models and experimental studies are described. Optimization of an autofrettage process is also discussed. Based on the review, some challenging issues and key areas for future research are identified.

Anomaly in the Chain Length Dependence of n-Alkane Diffusion in ZIF-4 Metal-Organic Frameworks.

Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n-alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n-butane was observed, followed by an increase for n-pentane, and another decrease for n-hexane. This observation was confirmed by uptake measurements with n-butane/n-pentane mixtures, which yield faster uptake of n-pentane. Further evidence is provided by the observation of overshooting effects, i.e., by transient n-pentane concentrations exceeding the (eventually attained) equilibrium value. Accompanying grand canonical Monte Carlo simulations reveal, for the larger n-alkanes, significant differences between the adsorbed and gas phase molecular configurations, indicating strong confinement effects within ZIF-4, which, with increasing chain length, may be expected to give rise to configurational shifts facilitating molecular propagation at particular chain lengths.

Measurement of detector-corrected observables sensitive to the anomalous production of events with jets and large missing transverse momentum in varvec{pp} collisions at mathbf {sqrt{s}=13}\xa0TeV using the ATLAS detector

Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a Z/gamma ^* boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb^{-1} of proton–proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13 text {TeV} and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper.

Overbooking under dynamic and static policies

Overbooking, no-shows and cancellations are important aspects of revenue management with published research going back several decades. Yet, despite availability of a variety of theoretical models including dynamic ones, in practice, airlines today are still applying relatively simplistic static solutions. We analyze underlying reasons for this situation and investigate potential benefits as complexity of the solution method increases. We present a comparison of modeling overbooking for no-shows and cancellations using dynamic and static policies, and also analyze impact of the refund as well as denied boarding cost structures.

Habitats on the grid: The spatial dimension does matter for red-listing

Besides species Red Lists, recently, a variety of frameworks have been proposed for assessing higher levels of biological organisation, i.e. ecosystems, habitats, plant communities. Most of these protocols refer to ‘plant species assemblages’ or ‘vegetation types’ as proxies for ecosystems or habitats. Indeed, the habitat concept based on plant communities has acquired a central role as a key approach for biodiversity conservation above the species level. Plant communities, like every complex biological system, hold scale-dependent ‘emergent’ properties which vary as a function of the scale of observation. With reference to red-listing, these scale-dependent properties have far-reaching consequences for both identification and classification, as well as for representation and evaluation, and become particularly challenging when dealing with criteria regarding decline in distribution or restricted distribution. The recent discussion on the red-listing protocols has evidenced several aspects that claim special efforts for a suitable use. In the present paper, starting with the analysis of some recently proposed protocols for the red-listing of habitats and ecosystems, we discuss and test some ‘emergent’ properties of species assemblages, providing cues for reflection. Based on a variety of theoretical models and scientific outcomes in literature from the last decades, we theorise that plant communities own some intrinsic, ecologically based and scale-dependent spatial features, which give rise to different types of pattern of spatial occupancy. We discuss a model where, in natural conditions, the possible patterns of spatial occupancy are referred to 3 basic types: areal, linear and point. This approach is here proposed as a tool to discriminate among different broad categories of plant community-based habitat types and optimise their assessment in the red-listing process. Starting from a homogeneous data set, the proposed case studies prove that the choice of the scale affects the comprehension of the habitats’ occurrence, with a substantial relapse on the estimates of their distribution size. In particular, habitats with linear and point distribution, often naturally small in size and dispersed, are more susceptible to biased evaluation of their actual distribution and consequently of their threat status. The intrinsic spatial attributes of plant communities should not be neglected in a red-listing process and claim for a ‘habitat-tailored’ approach. The use of different grid-cell sizes and thresholds for the three main patterns of spatial occupancy here proposed, might certainly avoid inaccurate statements.

Apotemnophilia, body integrity identity disorder or xenomelia? Psychiatric and neurologic etiologies face each other

This review summarizes the available studies of a rare condition in which individuals seek the amputation of a healthy limb or desire to be paraplegic. Since 1977, case reports and group studies have been produced, trying to understand the cause of this unusual desire. The main etiological hypotheses are presented, from the psychological/psychiatric to the most recent neurologic explanation. The paradigms adopted and the clinical features are compared across studies and analyzed in detail. Finally, future directions and ethical implications are discussed. A proposal is made to adopt a multidisciplinary approach that comprises state-of-the-art technologies and a variety of theoretical models, including both body representation and psychological and sexual components.

The Logic of External Reform Resistance

Thanks in large part to survey efforts such as the Afrobarometer, scholars have developed and tested a variety of theoretical models explaining why citizens in sub-Saharan Africa hold supportive or, conversely, dissatisfied attitudes toward the economic and political reforms of the last several decades. Much of this research highlights citizens’ rational evaluation of the new regimes’ performance as the critical component. In this article, we advance an alternative argument, namely that citizens also care about the origins of these political and economic transformations. When citizens view these changes as externally imposed, they are less likely to develop supportive and satisfied attitudes toward the process of economic reform and democracy. Original interview data from Dakar, Senegal strongly supports our argument. The findings have important implications for a continent where economic and political institutions have long been shaped by outside actors.

Cognitive Process of Moral Decision-Making for Autonomous Agents

There are a great variety of theoretical models of cognition whose main purpose is to explain the inner workings of the human brain. Researchers from areas such as neuroscience, psychology, and physiology have proposed these models. Nevertheless, most of these models are based on empirical studies and on experiments with humans, primates, and rodents. In fields such as cognitive informatics and artificial intelligence, these cognitive models may be translated into computational implementations and incorporated into the architectures of intelligent autonomous agents (AAs). Thus, the main assumption in this work is that knowledge in those fields can be used as a design approach contributing to the development of intelligent systems capable of displaying very believable and human-like behaviors. Decision-Making (DM) is one of the most investigated and computationally implemented functions. The literature reports several computational models that enable AAs to make decisions that help achieve their personal goals and needs. However, most models disregard crucial aspects of human decision-making such as other agents' needs, ethical values, and social norms. In this paper, the authors present a set of criteria and mechanisms proposed to develop a biologically inspired computational model of Moral Decision-Making (MDM). To achieve a process of moral decision-making believable, the authors propose a cognitive function to determine the importance of each criterion based on the mood and emotional state of AAs, the main objective the model is to enable AAs to make decisions based on ethical and moral judgment.

Remix: Practice, Context, Culture

Remix: Practice, Context, Culture