Theoretical Estimates Research Articles

Репрезентативность показателей и объективность оценок в компаративистике: экономика Российской империи второй половины XIX столетия в современных зарубежных исследованиях

The relevance of comparative studies of the level of industrial and economic development of the Russian Empire in the second half of the XIX century is determined by the fact that their results in some cases are used to substantiate theoretical ideas about the national characteristics of the Russian economy and society in comparison with the leading countries of Industrial Revolution. In economic literature, assertions about the “catastrophic” backwardness of Russia during this period are often encountered. Modern foreign historical-economic research allows for a more objective assessment of the gap between the level of industrial and economic development of the Russian Empire and the “advanced” states. However, the authors of these studies do not always succeed in consistently applying the principle of uniform criteria for comparing different economies. In particular, it is hardly justified: in some cases, to take into account, and in others, not to take into account the population and economic potential of territorial isolated peripheral regions of the respective economies. For example, the value of historical and economic comparisons is reduced by the confusion in research between the actual territory of the Russian Empire in the middle and second half of the XIX century, its territory within the conditional “borders of 1913” and the territory within “former USSR” borders. In this regard the article notes that conclusions drawn on the basis of fragmentary and arbitrarily interpreted information can’t be considered as fully correct. According to the author, in a comparative analysis of the economies-leaders of the Industrial Revolution, it is necessary to use assessment methods that take into account the population and indicators of economic development of peripheral territories were included in trade and financial exchanges with these economies, because this inclusion strongly spired the development of economies-leaders.

A Comparative Study between Theoretical and Measured Performance of Standard Centrifugal Pumps Running as Turbines

High cost of custom-made conventional turbines and the lack of local manufacturing facilities have created significant obstacles to the development of Pico/micro hydroelectric schemes in the country. In this context it has been identified pump as turbine (PAT) electric schemes can have distinct advantages over conventional turbines because pumps are manufactured locally at mass scale and available in various sizes. But not all pumps are suitable for use as PAT because they have different design details and manufacturing qualities. The performance of a pump used as a turbine is assessed based on two primary parameters: turbine mode head and flow at the Best Efficiency Point (BEP). There are various methods available in the literature for predicting PAT theoretical head and flow at BEP. These methods aim to estimate how the pump will perform when used as a turbine. Despite these prediction methods, there is a consistent deviation of approximately ±20% between the theoretical estimates and the actual measured performance. This indicates that real-world conditions and factors not accounted for in theoretical models can significantly affect the performance of PAT systems. The primary objective of the present study was to measure the deviation between the actual performance and the predicted performance of two PAT systems in terms of head and flow at BEP. This deviation was then compared to the commonly mentioned figure of ±20% in the literature. The study focused on using what it considered to be the most accurate prediction method among those presented in the literature to estimate PAT head and flow at BEP and involved running reverse, 1.1 kW, and 1.6 kW direct-drive standard centrifugal type water pumps in a test rig to measure the actual performance of the two PATs. The results of the study showed a deviation of +27% and -22% between the actual measured head and flow at BEP, and the values predicted by the theoretical method. This deviation is slightly outside the commonly mentioned range of ±20% found in the literature, but this is not expected to have a detrimental effect on the generation of electric power. This implies that, even with the observed slight deviation, the prediction method used in this study can be satisfactorily employed to estimate PAT head and flow at BEP.

Research on the Application of Soundscape Design in Domestic Suspense Films: A Case Study of Lost in the Stars

This paper takes the soundscape design of domestic suspense films as the research object, aiming to explore the classification, case analysis, and production process of soundscapes in domestic suspense films, and to propose innovative strategies. Firstly, by defining and classifying film soundscapes, the characteristics of soundscape design in domestic suspense films are summarized. Secondly, through a specific case study of Lost in the Stars, the application and effect of soundscape design in domestic suspense films are analyzed. Next, the production process of soundscapes in domestic suspense films in the digital cinema era is introduced, including sound design, simultaneous recording, post-production, mixing, and playback stages. Finally, innovative strategies for the soundscape design of domestic suspense films are proposed. This research aims to provide theoretical support and innovative ideas for the practice of soundscape design in domestic suspense films.

History and future of business ecosystem: a bibliometric analysis and visualization

AbstractThe business ecosystem theory has developed rapidly in recent years and has become a hot topic in the field of business and management. However, the use of this concept is controversial. This study systematically reviewed literature published spanning nearly three decades from 1993 to 2022. In this paper, researchers designed an improved traceability method to retrieve literature based on data sources form Web of Science. VOSviewer and CiteSpace are adopted as two scientific atlas tools for information processing and visualization to evaluate the relationship between sub fields of business ecosystem. The findings show that the four branches of business ecosystem, i.e., innovation, platform, entrepreneurship and service, absorb theoretical ideas to varying degrees. Among them, the theoretical inheritance relationship of innovation branch is most clear, and gradually grows into the backbone of ecosystem research. Major contribution of this study is reflected in three aspects: Firstly, the improved traceability method provides a repeatable quantitative description process on the basis of significantly reducing researchers’ subjective participation. Secondly, from perspective of bibliometrics, the branch direction and key nodes of theory development are identified. Thirdly, the study helps identify the future development directions of business ecosystem, including innovation, digitalization, entrepreneurship, self-organization and the strategic transformation guided by emerging technologies.

Application of roughness models to stationary and rotating minichannel flows

PurposeThe performance of a bladeless Tesla turbine is closely tied to momentum diffusion, kinetic energy transfer and wall shear stress generation on its rotating disks. The surface roughness adds complexity of flow analysis in such a domain. This paper aims to assess the effect of roughness on flow structures and the application of roughness models in flow cross sections with submillimeter height, including both stationary and rotating walls.Design/methodology/approachThis research starts with the examination of flow over a rough flat plate, and then proceeds to study flow within minichannels, evaluating the effect of roughness on flow characteristics. An in-house test stand validates the numerical solutions of minichannel. Finally, flow through the minichannel with corotating walls was analyzed. The k-ω SST turbulent model and Aupoix's roughness method are used for numerical simulations.FindingsThe findings emphasize the necessity of considering the constricted dimensions of the flow cross section, thereby improving the alignment of derived results with theoretical estimations. Moreover, this study explores the effects of roughness on flow characteristics within the minichannel with stationary and rotating walls, offering valuable insights into this intricate phenomenon, and depicts the appropriate performance of chosen roughness model in studied cases.Originality/valueThe originality of this investigation is the assessment and validation of flow characteristics inside minichannel with stationary and corotating walls when the roughness is implemented. This phenomenon, along with the effect of roughness on the transportation of kinetic energy to the rough surface of a minichannel in an in-house test setup, is assessed.

Application of AI and VR Synergistic Enhancement in Employment Skills Training: A Virtual Simulation Approach

In recent years, the rapid development of artificial intelligence (AI) and virtual reality (VR) technology has opened up new approaches in the field of education and training, especially employment skills training. This study explores the application of artificial intelligence and virtual reality collaborative enhancement technology in virtual simulation training of employment skills. It introduces a comprehensive theoretical framework, including data collection and processing, intelligent analysis using multimodal algorithms, collaborative security mechanisms for AI models, and AI-VR interaction optimization techniques. This study confirms the feasibility and validity of the framework through theoretical analysis, simulation experiments, and expert interviews. The results show that the proposed framework significantly improves the personalization and interactivity of training, ensures data privacy and system stability, and improves the efficiency of intelligent diagnosis. This study provides valuable theoretical support and innovative ideas for the deep integration of VR technology in educational training.

Formation of Galactic Disks. II. The Physical Drivers of Disk Spin-up

Using a representative sample of Milky Way (MW)–like galaxies from the TNG50 cosmological simulation, we investigate physical processes driving the formation of galactic disks. A disk forms as a result of the interplay between inflow and outflow carrying angular momentum in and out of the galaxy. Interestingly, the inflow and outflow have remarkably similar distributions of angular momentum, suggesting an exchange of angular momentum and/or outflow recycling, leading to continuous feeding of prealigned material from the corotating circumgalactic medium. We show that the disk formation in TNG50 is correlated with stellar bulge formation, in qualitative agreement with a recent theoretical model of disk formation facilitated by steep gravitational potentials. Disk formation is also correlated with the formation of a hot circumgalactic halo with around half of the inflow occurring at subsonic and transonic velocities corresponding to Mach numbers of ≲2. In the context of recent theoretical works connecting disk settling and hot halo formation, our results imply that the subsonic part of the inflow may settle into a disk while the remaining supersonic inflow will perturb this disk via the chaotic cold accretion. We find that disks tend to form when the host halos become more massive than ∼(1–2) × 1011 M ⊙, consistent with previous theoretical findings and observational estimates of the predisk protogalaxy remnant in the MW. Our results do not prove that either corotating outflow recycling, gravitational potential steepening, or hot halo formation cause disk formation, but they show that all these processes occur concurrently and may play an important role in disk growth.

A mathematical modelling for solar irradiance reduction of sunshades and some near-future albedo modification approaches for mitigation of global warming

To address the global warming problem, one of the space-based geoengineering solutions suggests the construction of an occluding disc that can work as a solar curtain to mitigate solar irradiation penetration to the earth atmosphere. A widely discussed concept needs the construction of a large-scale sunshade system near the Sun–Earth L1 equilibrium point in order to control the average global temperature. However, to improve the accuracy of theoretical estimations, more consistent modeling of the Sun-Curtain-Earth system and solar irradiance reduction rate are required. This study revisits the mathematical modeling of the solar irradiance reduction system and considers the fundamentals of shading physics. Simplified mathematical modeling of solar irradiance reduction rate is derived based on the solar flux density. For the climate control, controllability of the reduction rate by using some physical parameters (e.g., flux reflection rate and angle of the curtain) is discussed. Based on the results of this model, the technical challenges and feasibility of constructing a sunshade system at L1 Lagrange point are evaluated. Some technologically feasible, near-future options for the warming problem are discussed briefly.

Unveiling the Reaction Mechanism of the N(2D) + Pyridine Reaction: Ring-Contraction versus 7-Membered-Ring Formation Channels.

Despite the relevance of the reactions of the prototypical nitrogen-containing six-membered aromatic molecule (N-heterocyclic) of pyridine (C6H5N) in environmental science, astrochemistry, planetary science, prebiotic chemistry, and materials science, few experimental/theoretical studies exist on the bimolecular reactions involving pyridine and neutral atomic/molecular radicals. We report a combined experimental and theoretical study on the elementary reaction of pyridine with excited nitrogen atoms, N(2D), aimed at providing information about the primary reaction products and their branching fractions (BFs). From previous crossed molecular beam (CMB) experiments with mass-spectrometric detection and present synergistic calculations of the reactive potential energy surface (PES) and product BFs we have unveiled the reaction mechanism. It is found that the reaction proceeds via N(2D) barrierless addition to pyridine that, via bridged intermediates followed by N atom "sliding" into the ring, leads to 7-membered-ring structures. They further evolve, mainly via ring-contraction mechanisms toward 5-membered-ring radical products and, to a smaller extent, via H-displacement mechanisms toward 7-membered-ring isomeric products and their isomers. Using the theoretical statistical estimates, an improved fit of the experimental data previously reported has been obtained, leading to the following results for the dominant product channels: C4H4N (pyrrolyl) + HCN (BF = 0.61 ± 0.20), C3H3N2 (1H-imidazolyl/1H-pyrazolyl) + C2H2 (BF = 0.11 ± 0.06), and C5H4N2 (7-membered-ring molecules or pyrrole carbonitriles) + H (BF = 0.28 ± 0.10). The ring-contraction product channels C4H4N (pyrrolyl) + HCN, C3H3N2 (1H-imidazolyl) + C2H2, C3H3N2 (1H-pyrazolyl) + C2H2, and C5H5 (cyclopentadienyl) + N2 have statistical BFs of 0.54, 0.09, 0.11, and 0.07, respectively. Among the H-displacement channels, the cyclic-CHCHCHCHNCN + H channel and cyclic-CHCHCHCHCN2 + H are theoretically predicted to have a comparable BF (0.07 and 0.06, respectively), while the other isomeric 7-membered-ring molecule + H channel has a BF of 0.03. Pyrrole-carbonitriles and 1H-ethynyl-1H-imidazole (+ H) isomeric channels have an overall BF of 0.03. Implications for the chemistry of Saturn's moon Titan and prebiotic chemistry, as well as for understanding the N-doping of graphene or carbon nanotubes, are noted.

Impacts of bulk density and water content on the tire-soil contact area of agricultural field vehicles

We tested the hypothesis that the increase in soil stiffness, induced by variations in bulk density and water content at the tire-soil contact interface, causes a reduction in the contact area. For this, we examined the contact area from different tire-ground contact scenarios and compared the measurements and simulations using a contact area description model. Front and rear tractor tires were used for the measurement of the contact area under tilled soil, sugarcane field, unpaved road, and paved ground scenarios, which induced different bulk densities and water content levels. The results revealed that soil stiffness reduced the tire-soil contact area. The tire-soil contact area increased as the water content increased and the bulk density was reduced. For the front tractor tire, the theoretical contact area was similar to the values found for tilled soil, but there was a large difference between the measurements (2,200 cm2, for the tilled soil) and the theoretical estimates (3,100 cm2) for the rear tractor tire (likely induced by tire dimensions). Our results suggest that increases in soil stiffness reduce the tire-soil contact area. The higher the soil bulk density and the lower the soil moisture, the lower the contact area. The results also revealed that the tire tractor tread might reduce the contact at the hard surface, making the shape of the contact area more geometrically irregular and different from those predicted by models using regular geometry (e.g., cycles, ellipses, or rectangles). This study suggests that two-body (soil and tire) contact models for deformable surfaces should be used in future tire-soil contact models of agricultural field vehicles.

Heat Flow Estimation in Polymer Films during Orientational Drawing at the Local Heater.

The optimization of the process of polymer film orientational drawing using the local heater was investigated. One of the problems with this technology is that the strength of the resulting fibers differs significantly from the theoretical estimates. It is assumed that one of the reasons is related to the peculiarity of this technology, when at the point of drawing the film is heated only on one side, which creates a temperature difference between the sides of the film in contact with the heater and the non-contact sides of the film in the air. Estimates show that even a small temperature difference of just 1 °C between these surfaces leads to a significant difference in the rate of plastic deformation of the corresponding near-surface layers. As a consequence, during hardening, in the stretching region, tensile stress is concentrated on the "cold" side of the film, and this effect can presumably lead to the generation of more defects overthere. It has been suggested that defects arising during first stage of hardening, namely, neck formation, can serve as a trigger for the formation of defects such as kink bands on the "cold" side with further orientational strengthening due to plastic deformation of the resulting fibrillar structure, at the boundaries of which microcracks are formed, leading to rupture of the oriented sample. The numerical calculation of heat propagation due to heat conduction in the film from the local surface of the heater is carried out and the temperature distribution along the thickness and width of the film during drawing is found. The temperature difference in the heated layer of the film between the contact and non-contact sides with the heater was calculated depending on the thickness of the film and the speed of its movement along the heater. It was found that the most homogeneous temperature distribution over the film thickness, which is required, by default, for the synchronous transformation of the unoriented initial folded lamellar structure into a fibrillar structure, is observed only for films with a thickness of less than 50 μm. The calculation allows us to scientifically justify the choice of orientation drawing speed and optimal thickness of the oriented polymer film, which is extremely important, for example, for obtaining super-strong and high-modulus UHMWPE filaments used in products for various purposes: from body armor to sports equipment and bioimplants.

How does digital innovation synergy improve the organisational resilience of ‘specialized, refined, differentiated, and innovative’ SMEs?

ABSTRACT Intricate and challenging environments profoundly impact enterprise development. Consequently, enhancing organisational resilience (OR) has emerged as a pressing concern. To demystify this, we draw on dynamic capability theory and employ fuzzy-set qualitative comparative analysis (fsQCA) to investigate how digital innovation (DI) synergistically configures across R&D, Production, and Scene dimensions to bolster OR over distinct periods. Focusing on 73 Chinese ‘specialized, refined, differentiated, and innovative’ (SRDI) SMEs, results show that (1) the single DI dimension is not necessary for OR, and the multi-dimensional DI synergy effectively enhances OR. (2) In each period, there are three equivalent DI configurations to improve OR. (3) In multi-period comparative analysis, DI configuration with R&D, Production, and Scene as constant core conditions manifests ‘turning trajectory’, ‘expansion trajectory’, and ‘transition trajectory’, respectively, in enhancing OR. This study expands the research perspective on SRDI SMEs and provides new theoretical and practical ideas for rationally configuring DI synergy across different periods.

Direct measurement of self-diffusiophoretic force generated by active colloids of different patch coverage using optical tweezers

Hypothesis: Synthetic micro/nanomotors are gaining extensive attention for various biomedical applications (especially in drug delivery) due to their ability to mimic the motion of biological micro/nanoscale swimmers. The feasibility of these applications relies on tight control of propulsion speed, direction, and type of motion (translation, circular, etc.) along with the exerted self-propulsive force. We propose to exploit the variation of both self-propulsion speed and force of active colloids with different patch coverages (with and without supporting layer) for engineering diffusiophoretic micro/nanomotors.Experiments: The microswimmers were designed at various patch coverages (10°, 30°, and 90°) with (Ti/Pt) and without (Pt) an adhesion layer for the catalytic patch through glancing angle metal deposition (GLAD) technique. Mean-square displacement (MSD) analysis was performed to obtain the self-propulsion parameters like speed and angular speed. Using optical tweezers (OT), the self-propulsive force was measured from the force power spectral density.Findings: The findings of our experiments suggest the non-requirement of any adhesion layer preceding the catalyst deposition since the Pt 10° colloidal batch had the maximal self-propulsion speed (4.61±0.3μm/s) and force (345±57fN) for 5% w/v H2O2 fuel concentration. Moreover, the self-propulsion speed and force decreased with increasing patch size, contrary to theoretical estimates. Also, the self-propulsive force obtained from MSD is 2 to 4 times lower in magnitude than the OT based force values. We believe that the self-propelling motion of the micromotors is possibly hindered due to interactions with the surface of the quartz cuvette during the optical microscopic analysis. Further, the MSD is limited to the self-propulsive motion in two dimensions. On the other hand, OT based force measurement involve trapping the particles in the bulk of the solution entirely avoiding the particle–substrate interactions. Hence, OT based force measurements are better than the propulsion velocity based stokes drag force estimates. We believe that this study can lay the foundation in designing efficient micro/nanomotors for translational biomedical applications.

Utopia in Dystopia: Presentation of the Landscape in Cormac McCarthy’s The Road

This paper explores the presentation of the utopian landscape in a dystopian world to impart the message of optimism in Cormac McCarthy’s novel The Road employing the theoretical ideas of ecocriticism focusing on the environmental apocalypse trend. The text as post-apocalyptic fiction presents the earth near destruction in relation to humans, animals and plants world after a frightening apocalypse. The two unnamed characters journey through the desolate landscape in search of safety. The landscape is full of silence and lifelessness, frightening and unfriendly for survival that tells a terrifying tale indeed. At the same time, the landscape is presented as a major component of the theme. More than that landscape itself is a text that needs interpretation as it has multiple possibilities. The world of the novel is dominated by a dystopian landscape. However, within that deadly world, the world of dream and memory is full of utopian landscape. This contrastive presentation seems purposeful. It is to keep the strand of hope and aware readers about the negative consequences, which the anthropocentric invasion to the natural system invites. Following qualitative research design, this paper uses textual analysis method to interpret the text with the critical ideas of Lawrence Buell related to the environmental apocalypse trend.

Optimization and experimental validation of deuterium-tritium neutron monoenergetics for diamond detector testing

Diamond detectors are excellent tools for measuring deuterium-tritium (D-T) neutron energy spectra. It has great potential for application in the field of magnetic confinement fusion. However, the current experimental values of the energy resolution of diamond detectors are much lower than the theoretical estimates. The purpose of this study is to find a method for experimental optimization. For this purpose, the D-T neutron energy distribution of the accelerator is theoretically analyzed and simulated. A method to increase the deuteron energy to obtain a better monoenergetic neutron source is proposed. This strategy was validated experimentally. The energy resolution of diamond for D-T neutrons achieves 1.21%, a Full Width at Half Maximum of 93 keV at 7.65 MeV. It is the highest resolution recorded to date. These results demonstrate the feasibility of the optimization method.

History of the development of the institute of law abuse in the states of the romano-german legal family

The article provides a historical analysis of the institution of abuse of law in the states of the Romano- Germanic legal family. In particular, with the help of a set of philosophical-worldview, general scientific, special scientific methods (primarily, dialectical, historical-legal and comparative-legal) and principles of scientific knowledge, the evolution of theoretical ideas about the abuse of law, their consolidation in legislation and practical implementation in individual states of the Romano-Germanic legal family (Germany, Austria, Switzerland, Spain, France). It is argued that modern ideas about the abuse of law are based on the provisions of Roman law. Theoretical approaches to the abuse of law contained in the works of leading European legal scholars (A. Binder, T. Geise, W. Erman, L. Dugis, W. Siebert, V. Roberto and others) were analyzed. On the basis of a comparative analysis of normative legal acts regulating the issue of abuse of law (German Civil Code, Austrian Civil Code, Civil Codes of Switzerland, Spain and France), characteristic features and general trends of the legal establishment of the category “abuse of law” in the states of the Romano- Germanic legal system have been revealed family. It was established that theoretical approaches to understanding the category of “law abuse” were most actively developed by scientists in Germany and France. In particular, general approaches to the essence and features of the abuse of the right have been developed, mechanisms for counteracting the harmful exercise of the right, etc. have been proposed. At the same time, the legislation of Germany, Austria, Switzerland, Spain and France also uses the experience of other countries, transforming it through their own culture and traditions. This is due to certain features of the legislative establishment of the inadmissibility of the abuse of the right. It was concluded that due to the existence in the states of the Romano-Germanic legal family of a general ban on the abuse of law, legal science had the opportunity to investigate not only specific cases of unfair exercise of the law, but also the phenomenon of abuse of law in general.

Excess acoustic and volumetric properties of polyethylene glycol 200 + methyl/ethyl methacrylate binary mixtures at different temperatures: An experimental and theoretical study

The excess and partial molar properties of binary liquid mixtures can be used to unveil the prevailing intermolecular interactions. The densities, ρ and speeds of sound, u for pure polyethylene glycol 200 (PEG 200), methyl methacrylate, ethyl methacrylate and their binaries (PEG 200 + methyl/ethyl methacrylate) have been measured over the entire composition range in the temperature range (293.15 to 323.15) K at 5 K intervals and at pressure, p = 100 kPa. The excess molar volume, excess isentropic compressibility, excess speed of sound, excess intermolecular free length, excess molar isentropic compressibility and excess acoustic impedance were evaluated using the experimental data. The partial and excess partial molar volumes/compressibilities of the components at each mole fraction and at infinite dilution have also been calculated. The results have been interpreted on the basis of prevailing intermolecular interactions as well as structural effects between like and unlike molecules. The results indicate the effect of the size of alkyl group on excess functions and interactions in these systems and the PEG-methacrylate interactions follow the order: methyl methacrylate > ethyl methacrylate. Scaled particle theory has also been used for the theoretical estimation of the speeds of sound and compared with experimental values. FT-IR spectra of pure PEG 200, methyl methacrylate, ethyl methacrylate and equimolar PEG 200 + methyl methacrylate/ethyl methacrylate mixtures were also recorded and analysed for better understanding of prevailing intermolecular interaction.

On accurate calculations of equilibrium H/D fractionations at super-cold conditions (≤200 K) I: Full Partition Function Ratio (FPFR) vs. Path Integral Monte Carlo (PIMC)

Accurate estimations of Hydrogen/Deuterium (H/D) isotope effects have been a long-standing problem since the beginning of stable isotope geochemistry, primarily due to their strong nuclear quantum effects (NQEs). Currently, the D/H ratio plays a key role in deciphering the origin and evolution of water ice and organics in the solar system. Additionally, the Big-bang origin of Deuterium necessitates that the observed D/H variations be linked to isotope exchange reactions, such as HD + H2O ↔ H2 + HDO. Therefore, an accurate benchmark dataset describing the equilibrium H/D isotope fractionations at low temperatures (≤ 200 K) is essential for interpreting rapidly accumulating astrochemical observation data. In this study, we implemented and compared two methods developed for evaluating the NQEs of H/D isotopes: 1) the Full Partition Function Ratio (FPFR) method and 2) the Path Integral Monte Carlo (PIMC) method. Both were assessed for their accuracy and efficiency in estimating equilibrium isotope effects (EIEs) using 10 common interstellar small molecules (H2, HF, HCl, HCN, HNC, H2O, H2S, NH3, HCHO, and CH4) as examples. Most of them are calculated at high precision for the first time. For the FPFR method, several higher-order corrections to the Urey-Bigeleisen-Mayer model were considered, including anharmonicity, quantum mechanical rotation with nuclear-spin statistics, and corrections to the Born-Oppenheimer approximation. For the PIMC method, four different actions related to the thermal density matrix are used. These include the primitive and three fourth-order actions (Takahashi and Imada, Suzuki-Chin and Chin approximations), based on the direct scaled-coordinates transformation. Three main conclusions are obtained: 1) Under the framework of Born-Oppenheimer approximation, the PIMC method holds the same and even slightly better accuracy (more comprehensive descriptions of quantum anharmonicities) in estimating EIEs for H/D isotopes as the FPFR method. However, both methods suffer from the neglection of the DBOC when using the Born-Oppenheimer potential energy surfaces. For the PIMC method, additional corrections for particle distinguishability must be considered when nuclear spin statistics exhibit its effects at low temperatures (e.g., < 160 K for H2). 2) Among the four actions, three fourth-order actions show better convergence and efficiency (2.2 to 26.5 times speedups at 50 K) than the primitive action, making them superior candidates for PIMC simulations at super-cold (≤ 200 K) conditions. 3) A combination of accurate potential energy surface with the PIMC method serves as an alternative way for theoretical estimations of H/D isotope effects.

Beyond reconsolidation: The need for a broad theoretical approach in clinical translations of research on retrieval-induced plasticity.

Experimental findings showing that retrieved memories are labile and vulnerable to disruption have led to important theoretical ideas at a basic science level that have been applied to the clinic at a translational level. At a theoretical level, these findings suggest that retrieved memories can be modulated by behavioral or pharmacological treatments as they are reconsolidated and returned to storage. At a clinical level, these findings suggest that treatments that target reconsolidation may help dampen or even erase especially problematic memories, such as those associated with trauma. However, there are many caveats to these effects and issues that need to be considered when thinking broadly about retrieval-induced plasticity and extensions into the clinic. First, performance during a memory test often does not reflect the entirety of the animal's knowledge about a situation; asking questions in different ways may reveal the presence of a memory that was thought to be eliminated. Second, although reconsolidation and extinction are often treated as competing processes, there is abundant evidence that extinction can progress through associative and nonassociative changes in the original memory that are often described in terms of reconsolidation effects. Third, targeting a reconsolidation process as a therapeutic may not be helpful in disorders like posttraumatic stress disorder, in which traumatic experiences induce a cascade of symptoms that are self-perpetuating and may ultimately maintain themselves long after trauma. Underlying all of these challenges is the need for a rich theoretical framework focused on retrieval-induced plasticity that is informed by developments in associative learning theory. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A Detailed Survey of the Parallel Mean Free Path of Solar Energetic Particle Protons and Electrons

In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well connected to at least one spacecraft at 1 au. The observed intensity–time profiles, for all available proton and electron energy channels, are compared to results computed using a numerical one-dimensional SEP transport model in order to derive the parallel mean free paths (pMFPs) as a function of energy (or rigidity) at 1 au. These inversion results are then compared to theoretical estimates of the pMFP, using observed turbulence quantities with observationally motivated variations as input. For protons, a very good comparison between inversion and theoretical results is obtained. It is shown that the observed inter-event variations in the inversion pMFP values can be explained by natural variations in the background turbulence values. For electrons, there is relatively good agreement with pMFPs derived assuming the damping model of dynamical turbulence, although the theoretical values are extremely sensitive to the details of the turbulence dissipation range, which themselves display a high level of variation.