Evolutionary Models Research Articles

How to Bridge Cognitive and Cultural Models of Religious Evolution

The scientific study of religion has roots in at least two traditions: a cognitive tradition which typically uses experimental studies to examine the proximal psychological processes underlying religious belief and ritual, and an anthropological tradition which uses historical and ethnographic data to examine how religious systems culturally evolve in social groups. In Religion Evolving, Purzycki and Sosis bridge both traditions and encourage a more integrated evolutionary science of religion. In this essay, I present three suggestions for how to make this science as ambitious and collaborative as possible. These suggestions are: (1) to move beyond straw man debates that pit byproduct models against functional models of religious evolution and acknowledge that these models are compatible from a dual inheritance perspective, (2) to evaluate functionalist claims with caution, recognizing how and when religion is adaptive vs. maladaptive for secular society, and (3) to avoid reductive definitions of religion and embrace religious pluralism. With these lessons in mind, we can usher in a bolder evolutionary science of religion that draws from both cognitive and cultural traditions.

Methods to Stimulate the Proactivity of Enterprises in Fulfilling Safety Responsibilities: A Fundamental Issue in Construction Safety Management

Management factors are among the most significant causes of construction safety incidents, and there is an issue of insufficient supervision at present. The degree of diligence exhibited by relevant entities is crucial, and the payoff can influence the decision-making behaviors of involved parties. Based on this, the aim of this paper is to investigate how to enhance the initiative of enterprises in fulfilling their safety responsibilities during the construction process. By developing a tripartite evolutionary game model that involves supervision companies, general contractors, and labor subcontractors and conducting numerical simulation analysis, we reveal that simultaneous proactive investment in safety by all three parties is challenging, with labor subcontractors being relatively more prone to opt for active safety investment. Supervision companies and general contractors often struggle to fulfill their safety duties at the same time. Factors such as the rewards and penalties stipulated in a contract, rent-seeking amounts, and accident-related losses have a significant impact on the evolution of the system. Based on the findings, we propose recommendations for construction management, which include the management of labor subcontracting in construction, the control of rent-seeking behaviors, and the establishment of a cooperative safety culture during the construction process.

The Relationship Between Astronomical and Developmental Times Emerging in Modeling the Evolution of Agents.

The simplest evolutionary model for catching prey by an agent (predator) is considered. The simulation is performed on the basis of a software-emulated Intel i8080 processor. Maximizing the number of catches is chosen as the objective function. This function is associated with energy dissipation and developmental time. It is shown that during Darwinian evolution, agents with an initially a random set of processor commands subsequently acquire a successful catching skill. It is found that in the process of evolution, a logarithmic relationship between astronomical and developmental times arises in agents. This result is important for the ideas available in the literature about the close connection of such concepts as time, Darwinian selection, and the maximization of entropy production.

Uncertainty of the white dwarf astrophysical gravitational wave background

The astrophysical gravitational wave background (AGWB) is a stochastic gravitational wave (GW) signal emitted by different populations of in-spiralling binary systems containing compact objects throughout the Universe . In the frequency range between 10$^ $ and 10$^ $ hertz (Hz), it will be detected by future space-based gravitational wave detectors, such as Laser Interferometer Space Antenna (LISA). In a recent work, we concluded that the white dwarf (WD) contribution to the AGWB dominates that of black holes (BHs) and neutron stars (NSs) We aim to investigate the uncertainties of the WD AGWB that arise from the use of different stellar metallicities, star formation rate density (SFRD) models, and binary evolution models. We used the code we previously developed to determine the WD component of the AGWB. We used a metallicity-dependent SFRD based on an earlier work to construct five different SFRD models. We used four different population models based on a range of common-envelope treatments and six different metallicities for each model. For all possible combinations, the WD component of the AGWB is dominant over other populations of compact objects. The effects of metallicity and population model are less significant than the effect of a (metallicity dependent) SFRD model. We find a range of about a factor of 5 in the level of the WD AGWB around a value of $ WD $ at 1 mHz and a shape that is weakly dependent on the model. We find the uncertainty for the WD component of the AGWB to be about a factor of 5. We note that there are other uncertainties that have an effect on this signal as well. We discuss whether the turnover of the WD AGWB at 10 mHz will be detectable by LISA and find it to be likely. We confirm our previous findings asserting that the WD component of the AGWB dominates over other populations, in particular, BHs.

The spatial-temporal evolution patterns of landslide-oriented resilience in mountainous city: A case study of Chongqing, China

Cities, as complex systems with multi-interconnected subsystems, face significant challenges from both rapid urbanization and climate change. Ensuring high resilience in urban areas is essential for managing these dynamic risks effectively. This study introduces an innovative, data-driven approach to quantitatively analyze the spatial-temporal evolution patterns of urban resilience, validated through a case study of Chongqing, a representative mountainous city in China. Based on historical landslide data from Chongqing (2010–2020), which includes 4464 events, along with indicator data from the Chongqing Statistical Yearbook, we developed a comprehensive assessment framework. This framework incorporates 33 variables, covering indicators of physical-environmental resilience (PER) and socio-economic resilience (SER). The model integrates the Random Forest (RF) algorithm, Analytic Hierarchy Process (AHP), and Coupling Coordination Degree (CCD) model. Key findings include: (1) Social development in mountainous cities like Chongqing follows a point-to-area pattern. Although there is an overall increase in SER, the CCD in more developed areas (Chongqing urban circle) was generally higher than in less developed areas (northeastern and southeastern Chongqing) (2) The PER model demonstrated exceptional performance (AUC values consistently above 0.95). Spatiotemporal evolution models reveal that Chongqing maintains a high overall PER. Notably, from 2019 to 2020, the proportion of administrative units classified as highly resilient peaked at 24.5%, marking a historical high. (3) Multi-year average rainfall primarily impacts PER (ranked first), while Gross Domestic Product (GDP) significantly affect SER. The development of multi-dimensional recovery indicators provides a robust framework for assessing resilience against landslides in mountainous cities. The CCD model illustrates the importance of regional dynamic coordinated development in resilience trajectories. This study provides a detailed blueprint for the scientific development of resilient mountainous cities, emphasizing the need for a spatial-temporal perspective on resilience and the benefits of coordinated regional development.

Evolution and simulation optimization of rural settlements in urban-rural integration areas from a multi-gradient perspective: A case study of the Lan-Bai urban agglomeration in China

With the rapid growth of global urbanization, rural land has been continuously occupied, which has brought about profound changes in human-land relationship. As a rural regional system in the frontier area of urbanization, the rural settlements in the urban-rural integration area (URIA) are in a profound transformation due to multiple disturbances such as internal natural factors and social and economic factors brought about by external urbanization. Based on the internal and external system factors of rural settlements, this paper constructs an analytical framework to explore the spatial and temporal evolution pattern of URIA rural settlements from 2000 to 2020, and then summarizes its evolution model, and predicts the situation of rural settlements in different scenarios in 2030. Finally, the optimal control strategy is proposed. The results show that: (1) From 2000 to 2020, affected by the gradient of natural environment, the scale of rural settlements in URIA shows a trend of decreasing in low-altitude areas near rivers and increasing in high-altitude areas far from rivers. Under the socio-economic gradient, there is a phenomenon that the scale of rural settlements in the inner edge of URIA with better socio-economic environment decreases and the scale of settlements in the outer area of URIA with poor socio-economic environment increases. (2) Based on different environmental factors, in the internal natural environment, it shows the evolution mode of “terrain containment” and “water source guidance”, while in the socio-economic environment, it shows the evolution mode of “urban sprawl encroaches rural”, “population decrease and land increase”. (3) The simulation results of rural settlements in 2030 show that the scale of rural settlements in the periphery of URIA continues to increase under the natural development (ND) scenario, while the scale of rural settlements in the inner edge decreases and the distribution is scattered. Under the urban-rural integration development (URD) scenario, rural settlements are mainly concentrated in the core area of URIA, and the area of rural settlements turning into urban land has dropped significantly. (4) Based on different gradients, the settlements are divided into three types: centralized development type, restricted development type and migration remediation type. Patch reconstruction is carried out by gravity model, which can theoretically save land and vacate 327 hm2 of construction land index. Compared with the extensive development model of the ND scenario, the URD scenario has important theoretical significance in limiting the blind expansion of the city and realizing the integration of urban and rural development in Lanbai.

A 650-Myr history of Earth's axial precession frequency and the evolution of the Earth-Moon system derived from cyclostratigraphy.

The preservation of Milankovitch cycles in the stratigraphic record provides independent geological information to study our ancient solar system and can be leveraged to constrain existing theoretical models. Here, we identify 34 high-quality cyclostratigraphic records spanning the past 650 million years and use them to infer the evolution of the Earth-Moon system through a Bayesian inversion method. We reconstruct the time evolution of Earth's axial precession frequency, lunar distance, length of day, and the periods of obliquity and climatic precession cycles. The results indicate an interval of high tidal energy dissipation in the Earth-Moon system at ~300 to 200 million years ago, and are broadly consistent with an independently calculated tidal evolution model. Our results provide an improved determination of the past periods of obliquity and climatic precession for astrochronology applications and yield important constraints on the history of tidal energy dissipation during the Phanerozoic Eon.

Prediction of potential conflicts between active targets in airport flight zones based on LSTM

Aiming at the problem of constant conflicts in airport flight zones, a method based on LSTM to predict potential conflicts of active targets in airport flight zones is proposed. Firstly, based on the complex network theory, two types of active targets, aircraft and vehicles, are taken as the research objects, and the flight zone active target network is established. The network dynamic evolution model is set up, and the operation data is input to calculate multiple network characteristic indicators. The principal component analysis of the indicator time series is performed to fit the potential conflict index; then, the Keras framework is used to build a long short-term memory neural network (LSTM) model, and the indicator time series is input into LSTM for training and prediction, and compared with other prediction methods; finally, the actual operation data of Xi'an Xianyang Airport is used for experiments, and the predicted values are compared with the true values. The mean square errors of the prediction results of each indicator are respectively 1.61%、13.13%、0.72%、0.004%、0.014%; The research shows that by establishing the flight zone active target network model, the network characteristic indicators can be used to characterize potential conflicts from different angles; LSTM can effectively predict the potential conflicts of the flight zone active target network, remind relevant personnel to pay attention to preventing conflicts and reducing the probability of conflicts.

On the nature of the eccentric eclipsing binary star SY Phe with a pulsating γ Dor component

ABSTRACT Spectroscopic observations of the eccentric binary system SY Phe were made at the South African Astronomical Observatory in 2019, 2020, and 2021, and its mid-resolution spectra were obtained. The radial velocities of the component stars were measured using the cross-correlation method and Fourier disentangling of the spectra. The spectral type (hence the effective temperature) of the primary star was determined from a model-atmosphere analysis. The radial velocity and Transiting Exoplanet Survey Satellite (TESS) light curves of the system were analysed, and its absolute parameters were derived. A strong (5.2 mmag) periodic signal with a frequency typical of $\gamma$ Dor stars (1.169 cycles per day) dominates the Fourier spectrum of the light curve between the eclipses. Apsidal motion parameters of SY Phe were calculated by studying eclipse timing variations. The Geneva evolution models indicate an evolutionary age of 2 Gyr and solar metallicity for the primary component; however, although the position of the secondary component in the H–R diagram matches the isochrone of 2 Gyr, it appears to have a larger radius and higher effective temperature than expected for its determined mass. Here, the secondary component has too large a radius, which is in accordance with the radius discrepancy problem that has been encountered in other studies, especially in late-type dwarfs, and has not been solved for half a century.

Hard jet substructure in a multistage approach

We present predictions and postdictions for a wide variety of hard jet-substructure observables using a multistage model within the framework. The details of the multistage model and the various parameter choices are described in []. A novel feature of this model is the presence of two stages of jet modification: a high-virtuality phase [modeled using the modular all twist transverse-scattering elastic-drag and radiation model ()], where modified coherence effects diminish medium-induced radiation, and a lower virtuality phase [modeled using the linear Boltzmann transport model ()], where parton splits are fully resolved by the medium as they endure multiple scattering induced energy loss. Energy-loss calculations are carried out on event-by-event viscous fluid dynamic backgrounds constrained by experimental data. The uniform and consistent descriptions of multiple experimental observables demonstrate the essential role of modified coherence effects and the multistage modeling of jet evolution. Using the best choice of parameters from [], and with no further tuning, we present calculations for the medium modified jet fragmentation function, the groomed jet momentum fraction zg and angular separation rg distributions, as well as the nuclear modification factor of groomed jets. These calculations provide accurate descriptions of published data from experiments at the Large Hadron Collider. Furthermore, we provide predictions from the multistage model for future measurements at the BNL Relativistic Heavy Ion Collider. Published by the American Physical Society 2024

Prediction of post-PCV13 pneumococcal evolution using invasive disease data enhanced by inverse-invasiveness weighting.

After introducing pneumococcal conjugate vaccines (PCVs), serotype replacement occurred in Streptococcus pneumoniae. Predicting which pneumococcal strains will become common in carriage after vaccination can enhance vaccine design, public health interventions, and understanding of pneumococcal evolution. Invasive pneumococcal isolates were collected during 1998-2018 by the Active Bacterial Core surveillance (ABCs). Carriage data from Massachusetts (MA) and Southwest United States were used to calculate weights. Using pre-vaccine data, serotype-specific inverse-invasiveness weights were defined as the ratio of the proportion of the serotype in carriage to the proportion in invasive data. Genomic data were processed under bioinformatic pipelines to define genetically similar sequence clusters (i.e., strains), and accessory genes (COGs) present in 5-95% of isolates. Weights were applied to adjust observed strain proportions and COG frequencies. The negative frequency-dependent selection (NFDS) model predicted strain proportions by calculating the post-vaccine strain composition in the weighted invasive disease population that would best match pre-vaccine COG frequencies. Inverse-invasiveness weighting increased the correlation of COG frequencies between invasive and carriage data in linear or logit scale for pre-vaccine, post-PCV7, and post-PCV13; and between different epochs in the invasive data. Weighting the invasive data significantly improved the NFDS model's accuracy in predicting strain proportions in the carriage population in the post-PCV13 epoch, with the adjusted R2 increasing from 0.254 before weighting to 0.545 after weighting. The weighting system adjusted invasive disease data to better represent the pneumococcal carriage population, allowing the NFDS mechanism to predict strain proportions in carriage in the post-PCV13 epoch. Our methods enrich the value of genomic sequences from invasive disease surveillance.IMPORTANCEStreptococcus pneumoniae, a common colonizer in the human nasopharynx, can cause invasive diseases including pneumonia, bacteremia, and meningitis mostly in children under 5 years or older adults. The PCV7 was introduced in 2000 in the United States within the pediatric population to prevent disease and reduce deaths, followed by PCV13 in 2010, PCV15 in 2022, and PCV20 in 2023. After the removal of vaccine serotypes, the prevalence of carriage remained stable as the vacated pediatric ecological niche was filled with certain non-vaccine serotypes. Predicting which pneumococcal clones, and which serotypes, will be most successful in colonization after vaccination can enhance vaccine design and public health interventions, while also improving our understanding of pneumococcal evolution. While carriage data, which are collected from the pneumococcal population that is competing to colonize and transmit, are most directly relevant to evolutionary studies, invasive disease data are often more plentiful. Previously, evolutionary models based on negative frequency-dependent selection (NFDS) on the accessory genome were shown to predict which non-vaccine strains and serotypes were most successful in colonization following the introduction of PCV7. Here, we show that an inverse-invasiveness weighting system applied to invasive disease surveillance data allows the NFDS model to predict strain proportions in the projected carriage population in the post-PCV13/pre-PCV15 and pre-PCV20 epoch. The significance of our research lies in using a sample of invasive disease surveillance data to extend the use of NFDS as an evolutionary mechanism to predict post-PCV13 population dynamics. This has shown that we can correct for biased sampling that arises from differences in virulence and can enrich the value of genomic data from disease surveillance and advance our understanding of how NFDS impacts carriage population dynamics after both PCV7 and PCV13 vaccination.

Modified crystal plasticity constitutive model considering tensorial properties of microstructural evolution and creep life prediction model for Ni-based single crystal superalloy with film cooling hole

Accurate assessment of the creep life of film cooling hole structures is critical for long-life design and safe operation of aero engines and gas turbines. Firstly, through the high temperature creep experiment of nickel-based single crystal superalloy with film cooling hole, the microstructure evolution process under multiaxial stress state around film hole is characterized. Then, considering the directional effect of rafting structure and the influence of multiaxial stress, a fourth-order tensor is used to describe the evolution of γ phase width, and the microstructure evolution model accounting for multi-axial stress states is established. The microstructure evolution is coupled into the crystal plasticity constitutive model by Orowan stress. Meanwhile, based on continuous damage mechanics, a new multiaxial damage evolution law is established by introducing a multiaxial ductility factor into the constitutive model. The improved crystal plasticity constitutive model can effectively predict the microstructural evolution under multiaxial stress conditions. Furthermore, the combination of the modified crystal plasticity constitutive model and the critical distance method considering stress gradients is used for life prediction of film cooling hole structures. The prediction results show the effectiveness and necessity of considering the microstructure evolution in the life prediction.

Bridging the gap between Quebec and Newfoundland: new insights on the protracted and diachronic history of the Anticosti foreland basin

The offshore part of the Anticosti foreland basin between Gaspé Peninsula (Quebec) and western Newfoundland has been investigated for its petroleum potential, mainly in the 1980s, but its geometry and evolution remain poorly documented. In this study, short-wavelength magnetic markers associated with intra-sedimentary magnetic susceptibility contrasts are interpreted in conjunction with high-resolution seismic data to map the distribution of rock units. Magnetic markers associated with igneous dykes are distinguished from those associated with sedimentary units by their higher amplitude and geometry. Conjunct interpretation of magnetic and seismic datasets provides new insight on the geometry of the Anticosti Basin and indicates that: i) a relatively thick (~ 2 km) post-Llandovery (post- Jupiter Formation) sedimentary succession occurs in the core of two regional synclines where youngest preserved sediments are interpreted as correlative with the Upper Gaspé Sandstone Group - Red Island Road Formation (Emsian–Eifelian); ii) post-Eifelian (Acadian) deformation consists of a series of folds, 2–10 km in wavelength in the Honguedo Strait, north of the Gaspé Peninsula, and to a single greater wavelength fold in the Strait of Belle Isle; iii) newly recognized NW-striking faults that parallel the eastern Gaspé Peninsula shoreline exhibit significant syn- to post-Middle Mississippian movements; iv) the southern boundary of the Anticosti Basin corresponds either to the unconformity at the base of the Carboniferous–Permian Magdalen Basin or to previously poorly documented ESE to NE-striking faults; v) a series of dykes trend from N90° near Gaspé Peninsula to N170° between Anticosti and Newfoundland islands. These new findings are integrated in an evolution model that enhances the stratigraphic and tectonic along-strike variability of the Anticosti foreland basin.

A fitness distribution law for amino-acid replacements.

The effect of replacing the amino acid at a given site in a protein is difficult to predict. Yet, evolutionary comparisons have revealed highly regular patterns of interchangeability between pairs of amino acids, and such patterns have proved enormously useful in a range of applications in bioinformatics, evolutionary inference, and protein design. Here we reconcile these apparently contradictory observations using fitness data from over 350,000 experimental amino acid replacements. Almost one-quarter of the 20 × 19 = 380 types of replacements have broad distributions of fitness effects (DFEs) that closely resemble the background DFE for random changes, indicating an overwhelming influence of protein context in determining mutational effects. However, we also observe that the 380 pair-specific DFEs closely follow a maximum entropy distribution, specifically a truncated exponential distribution. The shape of this distribution is determined entirely by its mean, which is equivalent to the chance that a replacement of the given type is fitter than a random replacement. In this type of distribution, modest deviations in the mean correspond to much larger changes in the probability of falling in the far right tail, so that modest differences in mean exchangeability may result in much larger differences in the chance of a highly fit mutation. Indeed, we show that under the assumption that purifying selection filters out the vast majority of mutations, the maximum entropy distributions of fitness effects inferred from deep mutational scanning experiments predict the characteristic patterns of amino acid change observed in molecular evolution. These maximum entropy distributions of mutational effects not only provide a tuneable model for molecular evolution, but also have implications for mutational effect prediction and protein engineering.

Role of Cosmological Models in Organic Evolution in Space

Using the dynamic Friedman-Robertson-Walker Cosmological Model of the universe, the possibility of organic evolution in Space in the early universe is explored. According to this model, the universe is expected to perform simple harmonic motion between expansion and contraction. At the end of contraction, the universe assumes the smallest possible finite size with no boundary, while the entire mass of the universe gathers together as gravity particles, or gravity waves, at the center of gravity of universe. As soon as the density of the gravity particles is extremely high and the temperature reaches the flame temperature, a sudden violent explosion hurls the entire material into space uniformly in all directions when the expansion starts. It is in this period of expansion where the precursors of DNA/RNA, such as water, oxides of phosphorus, sugars, heterocyclic bases, compounds of nitrogen, etc. are formed.

TESS Detections of Pulsations in Of?p Stars in the Magellanic Clouds

We used Transiting Exoplanet Survey Satellite observations to search for pulsations in six known Of?p stars in the Magellanic Clouds. We find evidence for pulsational variability in three Of?p stars: UCAC4 115-008604, OGLE SMC-SC6 237339, and AzV 220. Two of them, UCAC4 115-008604 and OGLE SMC-SC6 237339, have been reported to possess kG-order magnetic fields. The obtained results are important to constrain and improve stellar evolution models.

Long range segmentation of prokaryotic genomes by gene age and functionality.

Bacterial and archaeal genomes encompass numerous operons that typically consist of two to five genes. On larger scales, however, gene order is poorly conserved through the evolution of prokaryotes. Nevertheless, non-random localization of different classes of genes on prokaryotic chromosomes could reflect important functional and evolutionary constraints. We explored the patterns of genomic localization of evolutionarily conserved (ancient) and variable (young) genes across the diversity of bacteria and archaea. Nearly all bacterial and archaeal chromosomes were found to encompass large segments of 100-300 kb that were significantly enriched in either ancient or young genes. Similar clustering of genes with lethal knockout phenotype (essential genes) was observed as well. Mathematical modeling of genome evolution suggests that this long-range gene clustering in prokaryotic chromosomes reflects perpetual genome rearrangement driven by a combination of selective and neutral processes rather than evolutionary conservation.

Is the Cyclic Model of the Universe Possible in the Relativistic Theory of Gravitation?

For the flat FLRW model of Universe evolution in RTG a new model of Dark Energy is proposed. It is a global scalar field Φ with the quadratic potential. It ensures cosmological acceleration at the present time and a bounce at the latе times. At the contraction stage Kazner-like growing anisotropy of Riemannian metrics will break a mass-of- the-graviton bounce mechanism near the Big Bang in FLRW case. There is also noncyclic option, when small enough graviton-mass-terms are significant only at the end of expansion. After bounce, during next contraction epoch, an anisotropy grows and the matter density finally reaches the Planck one.

Evolution of lithium in the disc of the Galaxy and the role of novae

Lithium plays a crucial role in probing stellar physics, stellar and primordial nucleosynthesis, and the chemical evolution of the Galaxy. Stars are considered to be the main source of Li, yet the identity of its primary stellar producer has long been a matter of debate. In light of recent theoretical and observational results, we investigate in this study the role of two candidate sources of Li enrichment in the Milky Way, namely asymptotic giant branch (AGB) stars and, in particular, novae. We utilised a one-zone Galactic chemical evolution (GCE) model to assess the viability of AGB stars and novae as stellar sources of Li. We used recent theoretical Li yields for AGB stars, while for novae we adopted observationally inferred Li yields and recently derived delay time distributions (DTDs). Subsequently, we extended our analysis by using a multi-zone model with radial migration to investigate spatial variations in the evolution of Li across the Milky Way disc and compared the results with observational data for field stars and open clusters. Our analysis shows that AGB stars clearly fail to reproduce the meteoritic Li abundance. In contrast, novae appear as promising candidates within the adopted framework, allowing us to quantify the contribution of each Li source at the Sun's formation and today. Our multi-zone model reveals the role of the differences in the DTDs of Type Ia supernovae and novae in shaping the evolution of Li in the various galactic zones. Its results are in fair agreement with the observational data for most open clusters, but small discrepancies appear in the outer disc.

Exploring massive star early evolution: the case of the Herschel 36 A triple system

Abstract Theoretical models show that some massive stars have not yet arrived at the zero-age main-sequence (ZAMS) at the end of the accretion phase. At that time, they have lost their thick envelopes and thus could be optically visible. Although some candidates to optically observable ZAMS stars have been reported, the evolutionary status of none of them has been confirmed yet. The O-type triple system Herschel 36 A (H36A) is one of these candidates. We present the quantitative spectral analysis of the individual stellar components of H36A and investigate the evolutionary status of the system by contrasting main sequence and pre-main sequence models. Overall, the derived parameters suggest that the components of H36A could be pre-main sequence stars going through the very last contraction to the ZAMS. However, the possibility of them already being on the main sequence is not yet ruled out. This study highlights the importance of considering multiple evolutionary models and shows that H36A represents a key object for understanding massive star formation and early evolution.