Ideal Model Research Articles

The Ideal Model of Land Procurement and Compensation for Infrastructure Development (Public Interest) Based on Pancasila

Objective: This study aims to examine and encourage the transition of the ideal model of procurement and compensation for losses that have been generalized in the form of money in the context of land acquisition for public interest or infrastructure development. This study examines the role of law in the form of regulations regulating the provision of compensation in land acquisition for infrastructure development not only limited to the form of money but justified in the form of share ownership. To ensure welfare, balance and justice that reflect the values of Pancasila, for landowners, the ideal compensation model is given in the form of share ownership to residents who release their land. While the number of shares granted can be deliberated by the parties. Method: The method used is normative juridical with a conceptual approach and a statutory approach. Results and Conclusions: From the results of the study shows that the land acquisition mechanism is carried out through land rights release institutions to meet the criteria of subjects in acquiring land acquired not through transfer of rights but based on land controlled by the state so that the consequence is to provide compensation, Thus, an ideal land acquisition model through buying and selling or exchange is not possible. The ideal model can be adopted by land banks in carrying out their activities in the future, so that land acquisition for public interest or infrastructure development can run according to government needs. Originality / Value: This research contributes to the ideal model and sustainability of land acquisition for public interest by proposing the concept of compensation using shares in response to changes in the dynamics of national land management and sustainable economic development of communities in accordance with the values of Pancasila. This research underscores the importance of political commitment in encouraging investment models and community compensation, so that the paradigm of society develops. The value of this study lies in offering new perspectives and potential solutions to the mechanism of land acquisition in the public interest.

Exploring virus-host-environment interactions in a chemotrophic-based underground estuary

BackgroundViruses play important roles in modulating microbial communities and influencing global biogeochemistry. There is now growing interest in characterising their ecological roles across diverse biomes. However, little is known about viral ecology in low-nutrient, chemotrophic-based environments. In such ecosystems, virus-driven manipulation of nutrient cycles might have profound impacts across trophic levels. In particular, anchialine environments, which are low-energy underground estuaries sustained by chemotrophic processes, represent ideal model systems to study novel virus-host-environment interactions.ResultsHere, we employ metagenomic sequencing to investigate the viral community in Bundera Sinkhole, an anchialine ecosystem rich in endemic species supported by microbial chemosynthesis. We find that the viruses are highly novel, with less than 2% representing described viruses, and are hugely abundant, making up as much as 12% of microbial intracellular DNA. These highly abundant viruses largely infect important prokaryotic taxa that drive key metabolic processes in the sinkhole. Further, the abundance of viral auxiliary metabolic genes (AMGs) involved in nucleotide and protein synthesis was strongly correlated with declines in environmental phosphate and sulphate concentrations. These AMGs encoded key enzymes needed to produce sulphur-containing amino acids, and phosphorus metabolic enzymes involved in purine and pyrimidine nucleotide synthesis. We hypothesise that this correlation is either due to selection of these AMGs under low phosphate and sulphate concentrations, highlighting the dynamic interactions between viruses, their hosts, and the environment; or, that these AMGs are driving increased viral nucleotide and protein synthesis via manipulation of host phosphorus and sulphur metabolism, consequently driving nutrient depletion in the surrounding water.ConclusionThis study represents the first metagenomic investigation of viruses in anchialine ecosystems, and provides new hypotheses and insights into virus-host-environment interactions in such ‘dark’, low-energy environments. This is particularly important since anchialine ecosystems are characterised by diverse endemic species, both in their microbial and faunal assemblages, which are primarily supported by microbial chemosynthesis. Thus, virus-host-environment interactions could have profound effects cascading through all trophic levels.

Developmental energetics in the oviparous corn snake, Pantherophis guttatus, confirms a conservative evolutionary pattern in snakes

Eggs of oviparous reptiles are ideal models for studying evolutionary patterns of embryonic metabolism since they allow tracking of energy allocation during development. Analyzing oxygen consumption of whole eggs throughout development indicates three patterns among reptiles. Embryos initially grow and consume oxygen exponentially, but oxygen consumption slows, or drops before hatching in some species. Turtles, crocodilians, and most lizards follow curves with initial exponential increases followed by declines, whereas embryonic snakes that have been studied exhibit a consistently exponential pattern. This study measured oxygen consumption of corn snake, Pantherophis guttatus, embryos to determine if this species also exhibits an exponential increase in oxygen consumption. Individual eggs, sampled weekly from oviposition to hatching, were placed in respirometry chambers for 24-h during which oxygen consumption was recorded. Embryos were staged and carcasses and yolk were weighed separately. Results indicate steady inclines in oxygen consumption during early stages of development, with a rapid increase prior to hatching. The findings support the hypothesis that embryonic oxygen consumption of snakes differs from most other non-avian reptiles. Total energy required for development was determined based on calorimetry of initial yolk compared to hatchlings and residual yolk and by integration of the area under the curve plotting oxygen consumption versus age of embryos. The cost of development estimates based on these two methods were 6.4 and 10.0 kJ, respectively. Our results emphasize the unique physiological aspects of snake embryogenesis and illustrate how the study of physiological characteristics can contribute to the broader understanding of reptilian evolution.

Spectroscopic analysis of hot, massive stars in large spectroscopic surveys with de-idealized models

ABSTRACT Upcoming large-scale spectroscopic surveys with e.g. WEAVE (William herschel telescope Enhanced Area Velocity Explorer) and 4MOST (4-metre Multi-Object Spectroscopic Telescope) will provide thousands of spectra of massive stars, which need to be analysed in an efficient and homogeneous way. Usually, studies of massive stars are limited to samples of a few hundred objects, which pushes current spectroscopic analysis tools to their limits because visual inspection is necessary to verify the spectroscopic fit. Often uncertainties are only estimated rather than derived and prior information cannot be incorporated without a Bayesian approach. In addition, uncertainties of stellar atmospheres and radiative transfer codes are not considered as a result of simplified, inaccurate, or incomplete/missing physics or, in short, idealized physical models. Here, we address the question of ‘How to compare an idealized model of complex objects to real data?’ with an empirical Bayesian approach and maximum a posteriori approximations. We focus on application to large-scale optical spectroscopic studies of complex astrophysical objects like stars. More specifically, we test and verify our methodology on samples of OB stars in 30 Doradus region of the Large Magellanic Clouds using a grid of fastwind model atmospheres. Our spectroscopic model de-idealization analysis pipeline takes advantage of the statistics that large samples provide by determining the model error to account for the idealized stellar atmosphere models, which are included into the error budget. The pipeline performs well over a wide parameter space and derives robust stellar parameters with representative uncertainties.

A nonhuman primate model with Alzheimer’s disease-like pathology induced by hippocampal overexpression of human tau

BackgroundAlzheimer’s disease (AD) is one of the most burdening diseases of the century with no disease-modifying treatment at this time. Nonhuman primates (NHPs) share genetic, anatomical, and physiological similarities with humans, making them ideal model animals for investigating the pathogenesis of AD and potential therapies. However, the use of NHPs in AD research has been hindered by the paucity of AD monkey models due to their long generation time, ethical considerations, and technical challenges in genetically modifying monkeys.MethodsHere, we developed an AD-like NHP model by overexpressing human tau in the bilateral hippocampi of adult rhesus macaque monkeys. We evaluated the pathological features of these monkeys with immunostaining, Nissl staining, cerebrospinal fluid (CSF) analysis, magnetic resonance imaging (MRI), positron emission tomography (PET), and behavioural tests.ResultsWe demonstrated that after hippocampal overexpression of tau protein, these monkeys displayed multiple pathological features of AD, including 3-repeat (3R)/4-repeat (4R) tau accumulation, tau hyperphosphorylation, tau propagation, neuronal loss, hippocampal atrophy, neuroinflammation, Aβ clearance deficits, blood vessel damage, and cognitive decline. More interestingly, the accumulation of both 3R and 4R tau is specific to NHPs but not found in adult rodents.ConclusionsThis work establishes a tau-induced AD-like NHP model with many key pathological and behavioural features of AD. In addition, our model may potentially become one of the AD NHP models adopted by researchers worldwide since it can be generated within 2 ~ 3 months through a single injection of AAVs into the monkey brains. Hence, our model NHPs may facilitate mechanistic studies and therapeutic treatments for AD.

How audits fail according to accident investigations: A counterfactual logic analysis

AbstractDespite the reliance on safety auditing within organizations, comparatively limited research has studied the performance of safety auditing. When an investigation laments the “lack of audit quality” following an accident, what is meant by this statement? What contrasts a “good quality” audit from a “poor quality” audit? This study examined counterfactual logics (statements about alternative realities that did not occur but “could have” according to investigators) within 44 major accident reports to assess how audits are supposed to function and how they fall short of the ideal model. The content analysis yielded nine counterfactual auditing failures grouped into four categories. Contrary to the “ideal” model, audits (a) failed to facilitate an accurate understanding of threats by misinterpreting their saliency, (b) failed to facilitate timely action against threats by inadequately addressing the deterioration of known issues, (c) failed to facilitate effective management of issues, leading to confusion around the purpose and scope of audits, and d) failed to facilitate sufficient focus on threats by lacking focus on critical hazards and focusing on paperwork over operational issues or “failing silently” by missing threats while simultaneously praising performance. Practitioners should critically evaluate audits against these criteria and ensure audits effectively identify early warning signs.

Colonization dynamic and distribution of the endophytic fungus Microdochium bolleyi in plants measured by qPCR.

Microdochium bolleyi is a fungal endophyte of cereals and grasses proposed as an ideal model organism for studying plant-endophyte interactions. A qPCR-based diagnostic assay was developed to detect M. bolleyi in wheat and Brachypodium distachyon tissues using the species-specific primers MbqITS derived from the ITS of the ribosomal gene. Specificity was tested against 20 fungal organisms associated with barley and wheat. Colonization dynamics, endophyte distribution in the plant, and potential of the seed transmission were analyzed in the wheat and model plant B. distachyon. The colonization of plants by endophyte starts from the germinating seed, where the seed coats are first strongly colonized, then the endophyte spreads to the adjacent parts, crown, roots near the crown, and basal parts of the stem. While in the lower distal parts of roots, the concentration of M. bolleyi DNA did not change significantly in successive samplings (30, 60, 90, 120, and 150 days after inoculation), there was a significant increase over time in the roots 1 cm under crown, crowns and stem bases. The endophyte reaches the higher parts of the base (2-4 cm above the crown) 90 days after sowing in wheat and 150 days in B. distachyon. The endophyte does not reach both host species' leaves, peduncles, and ears. Regarding the potential for seed transmission, endophyte was not detected in harvested grains of plants with heavily colonized roots. Plants grown from seeds derived from parental plants heavily colonized by endophyte did not exhibit any presence of the endophyte, so transmission by seeds was not confirmed. The course of colonization dynamics and distribution in the plant was similar for both hosts tested, with two differences: the base of the wheat stem was colonized earlier, but B. distachyon was occupied more intensively and abundantly than wheat. Thus, the designed species-specific primers could detect and quantify the endophyte in planta.

Numerical eigenanalysis of continuum geodesic acoustic mode by ideal magnetohydrodynamic model

In this study, we have developed a new eigenvalue code to solve the three-variables ideal magnetohydrodynamic (MHD) equation in flux coordinate system with the help of a symbolic vector analysis module and an automatic numerical discretization module, which were developed with the use of symbolic computation technique and were greatly facilitated the development of toroidal full MHD eigenvalue code SCELT. It has been used to solve for unstable modes and the present work is dedicated to the more difficult challenge of MHD continua, which ordinarily come with spatial singularities. With this new code, we were able to perform numerical calculations to determine the continuum spectrum of geodesic acoustic modes (GAMs), as well as obtain eigenfunctions for both the perturbed plasma displacement and perturbed magnetic field, incorporating a sufficient number of components. Through our global calculations, we have provided numerical evidence of singularities in the eigenfunctions, characterized by the type s−s0−1 and Ins−s0 . Moreover, we have examined the spatial variations of GAM fluctuations in regions both near and far from the singular surface. Here s represents a flux function that characterizes the magnetic flux surfaces and s=s0 defines the singular surface. Additionally, we have investigated the effects of finite aspect ratio, non-circular cross sections as well as the asymmetry on the frequency and eigenfunction of continuum GAMs through numerical analysis.

Voltage-controlled non-axisymmetric vibrations of soft electro-active tubes with strain-stiffening effect

Material properties of soft electro-active (SEA) structures are significantly sensitive to external electro-mechanical biasing fields (such as pre-stretch and electric stimuli), which generate remarkable knock-on effects on their dynamic characteristics. In this work, we analyze the electrostatically tunable non-axisymmetric vibrations of an incompressible SEA cylindrical tube under the combination of a radially applied electric voltage and an axial pre-stretch. Following the theory of nonlinear electro-elasticity and the associated linearized theory for superimposed perturbations, we derive the nonlinear static response of the SEA tube to the inhomogeneous biasing fields for the Gent ideal dielectric model. Using the State Space Method, we efficiently obtain the frequency equations for voltage-controlled small-amplitude three-dimensional non-axisymmetric vibrations, covering a wide range of behaviors, from the purely radial breathing mode to torsional modes, axisymmetric longitudinal modes, and prismatic diffuse modes. We also perform an exhaustive numerical analysis to validate the proposed approach compared with the conventional displacement method, as well as to elucidate the influences of the applied voltage, axial pre-stretch, and strain-stiffening effect on the nonlinear static response and vibration behaviors of the SEA tube. The present study clearly indicates that manipulating electro-mechanical biasing fields is a feasible way to tune the small-amplitude vibration characteristics of an SEA tube. The results should benefit experimental work on, and design of, voltage-controlled resonant devices made of SEA tubes.

Land intensification use scenarios based on urban land suitability assessment of the national park

In designing national parks, it is important to balance land use with ecological protection and local socio-economic development. In the past decades, the national park has undergone landscape fragmentation and degradation of ecological functions due to climate change and land use change, especially in national parks with urban areas. Therefore, ecological environmental protection projects should include the assessment of land use when planning urban area development in the national park region. Consequently, we used the Land Suitability Evaluation (LSE) method, with 13 indicators for natural, social and ecological variables, to assess the suitability of the newly created national park for urban land use on the Tibetan Plateau. Combining results of the suitability assessment and the Cellular Automata (CA) method, three urban intensification scenarios were simulated for 2040: (1) unplanned, (2) intensified, and (3) strictly regulated urban growth boundaries (UGBs). The impact of land use on the normalized difference vegetation index (NDVI) was analyzed by remote sensing and GIS tools, and the landscape patterns of the three urban growth scenarios were calculated. Close to 87 % of the area was basically suitable, nearly 13 % was unsuitable, and only 0.06 % (43.4 km2–also included in the basically suitable) was suitable for urban land use. In 2040, the built-up areas are predicted to be 3.38, 2.71 and 2.32 times greater than in 2020 under the unplanned (without considering ecological restrictions), the intensive development (emphasizing the driving force of transportation and tourism on the expansion of built-up areas) and the strict control (maximizing ecological restrictions) scenarios, respectively. An ideal development model was used to balance ecological protection and population growth and economic development. The NDVI analysis revealed that the impact of land use on vegetation cover in the intensive development scenario was ranked as winter pastures > tourist development zones > summer pastures. It is concluded that the intensification scenario, with transport and tourism as the main spatial drivers, is the most desirable for the future coordination of ecological conservation and socio-economic development in the national park. This scenario may alleviate the current environmental pressure of livestock grazing on winter pastures in the national park on the Tibetan Plateau. However, realizing this model requires appropriate engineering design for town development. Future research should assess the impacts of urban growth on the ecological environment, with the aim to achieve sustainable urban development tailored to the various geographic regions.

Optimization of seawater desalination processes with the ideal reverse osmosis equation

The optimization of a membrane seawater desalination system is used to be a very complicated and time consuming process because tedious calculations are required to determine permeate recovery of the membrane system. This process can be greatly streamlined when the ideal reverse osmosis model is used to calculate the recovery of the membrane system. With this model, the pressure for a designated recovery can be determined conveniently and accurately from the basic parameters of a membrane system. Then the specific cost under various conditions can be calculated for the recovery. Finally, the recovery that minimized the specific cost for the permeate production can be easily determined graphically. The impacts of energy, membrane, feed water pretreatment, and concentrate handling on the optimal recovery of a membrane desalination process are demonstrated. The avoidance of a large number of equations and numerical integration in the determination of permeate recovery can greatly facilitate the optimization of design and operation of seawater desalination processes.

In-Gap Edge and Domain-Wall States in Largely Perturbed Phononic Su–Schrieffer–Heeger Lattices

Topological states of matter have attracted significant attention due to their intrinsic wave-guiding and localization capabilities robust against disorders and defects in electronic, photonic, and phononic systems. Despite the above topological features that phononic crystals share with their electronic and photonic counterparts, finite-frequency topological states in phononic crystals may not always survive. In this work, we discuss the survivability of topological states in Su–Schrieffer–Heeger models with both local and non-local interactions and larger symmetry perturbation. Although such a discussion is still about ideal mass-spring models, the insights from this study set the expectations for continuum phononic crystals, which can further instruct the application of phononic crystals for practical purposes.

Modeling of rigidly-constrained pure shear dielectric elastomer actuators: electromechanical coupling network method

The rigidly-constrained pure shear dielectric elastomer actuator (PS-DEA) has become one of the critical configurations in linear soft actuator design due to its excellent uni-directional actuation performance and convenient preparation process. However, the theoretical analyses are primarily conducted by employing ideal models and lack consideration of the lateral necking deformation of PS-DEA, which has an essential impact on the performance evaluation and optimal design of PS-DEA. Therefore, in this paper, a user subroutine that describing the behavior of the electromechanical behavior of DE in terms of the Gent free-energy model is developed, and then a parametric model of the PS-DEA is established. Different combinations of actuator parameters are obtained by Latin hypercube sampling, and the actuator’s performance under the parameters is simulated by the finite element method. The finite element results are taken as a sample set, and a BP neural network with three hidden layers is employed to train the samples and obtain a PS-DEA network prediction model, which is experimentally analyzed to validate its accuracy and effectiveness. The prediction model explores the influence of geometric and pre-stretching parameters on the actuator’s performance and obtains the difference between the ideal theoretical and the network prediction model under various parameters. The method in this paper provides a new design methodology and theoretical basis for developing high-performance DE actuators.

A Magnet Splicing Method for Constructing a Three-Dimensional Self-Decoupled Magnetic Tactile Sensor

Tactile sensory organs for three-dimensional (3D) force perception are essential for most living organisms and enable them to perform complex and sophisticated tasks to survive and evolve. Magnetic-based tactile sensors have been developed rapidly in recent years due to the exploitability of 3D force decoupling. Here, a method of magnet splicing is introduced, which can be applied to a magnetic tactile sensor to realize 3D self-decoupling of magnets’ displacements. This method enables the magnets to produce a completely consistent magnetic field distribution as the ideal magnetization model within a certain working range, eliminating the compensation and correction of the 3D magnetic flux density signal. This method carves out a new way for the practical application of 3D decoupling theory, showcasing the great potential in the fields of magnetic sensors and magnetic actuators.

RECONSTRUCTION OF EMPOWERMENT-BASED MARKETING PERFORMANCE RECOVERY FOR MICRO AND SMALL BUSINESSES IN INDONESIA

The Covid-19 pandemic has made most economic sectors, especially micro and small enterprises, stagnant and even bankrupt. This situation is what makes micro and small business enterprises change their sales strategy through digitalization schemes. The Covid-19 pandemic has indirectly prompted new changes in Indonesia's business style. Social media and marketplaces can become a new concept to make it easier for micro and small business actors to get more comprehensive marketing access. This study aims to initiate an ideal digital marketing adoption model for micro and small enterprise to restore economic conditions to their original state. The research method is an exploratory qualitative approach using primary data obtained from observations and interviews. The sampling technique used purposive sampling with the criteria of the sources being micro and small business actors assisted by the Department of Cooperatives and SMEs of Semarang, Surakarta, Grobogan, Pemalang, Purworejo. The flow of research analysis is data collection, data reduction, data presentation, and concluding. The results of this study indicate two alternative solution models, including training and startup development and training and scaleup development. The urgency of this research allows the government to carry out single submission online program management to minimize errors and monitor program progress. This solution model is expected to be a role model based on ta'awun (mutual relations) for other provincial governments in empowering micro and small business actors to become more optimal based on appropriate technology.

ID-SF-Fusion: a cooperative model of intent detection and slot filling for natural language understanding

PurposeIntent detection (ID) and slot filling (SF) are two important tasks in natural language understanding. ID is to identify the main intent of a paragraph of text. The goal of SF is to extract the information that is important to the intent from the input sentence. However, most of the existing methods use sentence-level intention recognition, which has the risk of error propagation, and the relationship between intention recognition and SF is not explicitly modeled. Aiming at this problem, this paper proposes a collaborative model of ID and SF for intelligent spoken language understanding called ID-SF-Fusion.Design/methodology/approachID-SF-Fusion uses Bidirectional Encoder Representation from Transformers (BERT) and Bidirectional Long Short-Term Memory (BiLSTM) to extract effective word embedding and context vectors containing the whole sentence information respectively. Fusion layer is used to provide intent–slot fusion information for SF task. In this way, the relationship between ID and SF task is fully explicitly modeled. This layer takes the result of ID and slot context vectors as input to obtain the fusion information which contains both ID result and slot information. Meanwhile, to further reduce error propagation, we use word-level ID for the ID-SF-Fusion model. Finally, two tasks of ID and SF are realized by joint optimization training.FindingsWe conducted experiments on two public datasets, Airline Travel Information Systems (ATIS) and Snips. The results show that the Intent ACC score and Slot F1 score of ID-SF-Fusion on ATIS and Snips are 98.0 per cent and 95.8 per cent, respectively, and the two indicators on Snips dataset are 98.6 per cent and 96.7 per cent, respectively. These models are superior to slot-gated, SF-ID NetWork, stack-Prop and other models. In addition, ablation experiments were performed to further analyze and discuss the proposed model.Originality/valueThis paper uses word-level intent recognition and introduces intent information into the SF process, which is a significant improvement on both data sets.

The rodent models of arteriovenous fistula.

Arteriovenous fistulas (AVFs) have long been used as dialysis access in patients with end-stage renal disease; however, their maturation and long-term patency still fall short of clinical needs. Rodent models are irreplaceable to facilitate the study of mechanisms and provide reliable insights into clinical problems. The ideal rodent AVF model recapitulates the major features and pathology of human disease as closely as possible, and pre-induction of the uremic milieu is an important addition to AVF failure studies. Herein, we review different surgical methods used so far to create AVF in rodents, including surgical suturing, needle puncture, and the cuff technique. We also summarize commonly used evaluations after AVF placement. The aim was to provide recent advances and ideas for better selection and induction of rodent AVF models. At the same time, further improvements in the models and a deeper understanding of AVF failure mechanisms are expected.

История развития института обязательного страхования

The author has revealed that compulsory insurance has been and remains a socially significant area, which is an integral part of the state. It is worth noting that insurance is a conservative field in which changes occur rather slowly. The formation of the insurance institute in Russia for a long time went in the same direction as insurance in more developed European countries. However, external factors (aggression, wars) and internal factors (enslavement of peasants, denial of private property, entrepreneurship, lack of insurance culture) played a significant role in reducing the pace of development and formation of the insurance institution. Of course, the insurance sector does not stand still in its development, therefore, the ideal model of compulsory insurance has not yet been formed, therefore, state influence should be directed at rationalizing existing types of compulsory insurance, as well as the development of new bills that regulate new insurance models.

Flatworm Transcriptomes Reveal Widespread Parasitism by Histophagous Ciliates.

Unicellular ciliates like Tetrahymena are best known as free-living bacteriovores, but many species are facultative or obligate parasites. These "histophages" feed on the tissues of hosts ranging from planarian flatworms to commercially important fish and the larvae of imperiled freshwater mussels. Here, we developed a novel bioinformatics pipeline incorporating the nonstandard ciliate genetic code and used it to search for Ciliophora sequences in 34 publicly available Platyhelminthes EST libraries. From 2,615,036 screened ESTs, we identified nearly 6,000 high-confidence ciliate transcripts, supporting parasitism of seven additional flatworm species. We also cultured and identified Tetrahymena from nine terrestrial and freshwater planarians, including invasive earthworm predators from the genus Bipalium and the widely studied regeneration models Dugesia japonica and Schmidtea mediterranea. A co-phylogenetic reconstruction provides strong evidence for the coevolution of histophagous Ciliophora with their Platyhelminthes hosts. We further report the antiprotozoal aminoglycoside paromomycin expels Tetrahymena from S. mediterranea, providing new opportunities to investigate the effects of this relationship on planarian biology. Together, our findings raise the possibility that invasive flatworms constitute a novel dispersal mechanism for Tetrahymena parasites and position the Platyhelminthes as an ideal model phylum for studying the ecology and evolution of histophagous ciliates.

Ab initio study of nuclear clustering in hot dilute nuclear matter

We present a systematic ab initio study of clustering in hot dilute nuclear matter using nuclear lattice effective field theory with an SU(4)-symmetric interaction. We introduce a method called light-cluster distillation to determine the abundances of dimers, trimers, and alpha clusters as a function of density and temperature. Our lattice results are compared with an ideal gas model composed of free nucleons and clusters. Excellent agreement is found at very low density, while deviations from ideal gas abundances appear at increasing density due to cluster-nucleon and cluster-cluster interactions. In addition to determining the composition of hot dilute nuclear matter as a function of density and temperature, the lattice calculations also serve as benchmarks for virial expansion calculations, statistical models, and transport models of fragmentation and clustering in nucleus-nucleus collisions.