Model Of Formation Research Articles

Color profiles of disk galaxies at z = 1–3 observed with JWST: Implications for outer-disk formation histories

We investigate the deconvolved color profiles of 223 disk galaxies at redshifts of $z=1$--3 observed by the James Webb Space Telescope (JWST) as part of the Cosmic Evolution Early Release Science survey (CEERS). The filters were selected to approximate the rest-frame $B-Y$ color, which is used to identify U-shaped color profiles ---those becoming progressively bluer with increasing radius, then turning redder beyond a specific point. We find that 36<!PCT!> of Type II (down-bending) disks exhibit U-shaped color profiles with a minimum at or near the disk break. In contrast, no Type I (single-exponential) disks and only 9<!PCT!> of Type III (up-bending) disks show such a profile. The presence of U-shaped color profiles in Type II disks likely arises from the interplay between a star-formation threshold and spiral- or bar-driven secular radial migration of older stars outward. The fraction of Type II disks exhibiting a U-shaped color profile remains almost consistent across two redshift bins, $z=1$--2 and $z=2$--3, but is significantly lower than that observed in the local Universe, likely because the secular process of radial migration at high redshift may not have had sufficient time to significantly influence the disk structure. The absence of U-shaped color profiles in Type II disks could point to rapid rather than secular radial star migration potentially caused by violent clump instabilities, transporting both younger and older stars to the outer disk. Our results provide useful constraints on the formation and evolution models of disk galaxies in the early Universe.

Adolescent identity styles and avatar perception: examining the link between identity formation and virtual representation

Identity formation is a fundamental developmental task during adolescence, significantly influenced by how individuals are judged by others. In today’s digital age, such judgements increasingly occur in virtual settings, where the focus often shifts from the user to their virtual representation, or avatar. One of the most relevant frameworks for understanding the process of identity formation is Michael Berzonsky’s social-cognitive model of identity formation, which identifies three distinct identity processing styles: informational, normative, and diffuse-avoidant. This study explores whether correlations exist between adolescent identity styles and external judgements of their avatars. The sample consisted of 130 adolescents (75 females, 55 males), aged between 15 to 17 years. The research participants were instructed to create their own avatars and subsequently control their movements within an arcade game. Following this, the participants completed the Identity Style Questionnaire to determine their identity processing style. Field experts then evaluated the adolescents’ avatars based on several dimensions: masculinity/femininity of the nickname, unconventionality of the nickname, masculinity/femininity of the character, style of clothing (extravagance), attractiveness, friendliness, intelligence, sociability, and trustworthiness of the character, as well as character’s activeness and openness to experience. The results revealed significant correlations between the informational and normative identity styles and the avatars’ physical and psychological attributes as evaluated by experts. These findings provide valuable insights from a developmental psychology perspective and hold practical implications for interdisciplinary collaborations between psychologists and developers, particularly in designing educational and therapeutic computer games.

Timely TGFβ signalling inhibition induces notochord.

The formation of the vertebrate body involves the coordinated production of trunk tissues from progenitors located in the posterior of the embryo. Although in vitro models using pluripotent stem cells replicate aspects of this process1-10, they lack crucial components, most notably the notochord-a defining feature of chordates that patterns surrounding tissues11. Consequently, cell types dependent on notochord signals are absent from current models of human trunk formation. Here we performed single-cell transcriptomic analysis of chick embryos to map molecularly distinct progenitor populations and their spatial organization. Guided by this map, we investigated how differentiating human pluripotent stem cells develop a stereotypical spatial organization of trunk cell types. We found that YAP inactivation in conjunction with FGF-mediated MAPK signalling facilitated WNT pathway activation and induced expression of TBXT (also known as BRA). In addition, timely inhibition of WNT-induced NODAL and BMP signalling regulated the proportions of different tissue types, including notochordal cells. This enabled us to create a three-dimensional model of human trunk development that undergoes morphogenetic movements, producing elongated structures with a notochord and ventral neural and mesodermal tissues. Our findings provide insights into the mechanisms underlying vertebrate notochord formation and establish a more comprehensive in vitro model of human trunk development. This paves the way for future studies of tissue patterning in a physiologically relevant environment.

Development and validation of a clinical prediction model for blastocyst formation during IVF/ICSI-ET

PurposeThis study aims to create and validate a clinical model that predict the probability of blastocyst formation in IVF/ICSI-ET cycles.MethodsThis study employed a retrospective methodology, gathering data from 4961 cleavage-stage embryos that cultured in the reproductive center’s of the Fourth Hospital of Hebei Medical University between June 2020 and March 2024. 3472 were in the training set and 1489 were in the validation set when it was randomly split into the training set and validation set in a 7:3 ratio. The study employed both univariate and multivariate logistic regression analysis to determine the factors those influence in the process of blastocyst formation. Based on the multiple regression model, a predictive model of blastocyst formation during IVF was created. The calibration and decision curves were used to assess the effectiveness and therapeutic usefulness of this model.ResultsThe following factors independently predicted the probability of blastocyst formation: the method of insemination, number of oocytes retrieved, pronuclear morphological score, the number of cleavage ball, cleavage embryo symmetry, fragmentation rate and morphological score and basal P levels of female. The receiver operating characteristic curve’s area under the curve (AUC) in the training set is 0.742 (95% CI: 0.724,0.759), while the validation set’s AUC is 0.729 (95% CI: 0.703,0.755), indicating a rather high clinical prediction capacity.ConclusionOur generated nomogram has the ability to forecast the probability of blastocyst formation in IVF, hence can assist clinical staff in making informed decisions.

Underwater Image Refinement: Color Distanceand Image Formation Model (DIMFM)

Underwater Image Refinement: Color Distanceand Image Formation Model (DIMFM)

Study on Development Characteristics and Reservoir Formation Model of Lower Ordovician Reservoirs in Central Sichuan

Sichuan Basin is a large superimposed petroliferous basin, which has experienced multi-stage extension-convergence cycle and has great potential of oil and gas resources. In recent years, the lower combination oil and gas exploration in the middle Sichuan area has made great breakthroughs in the Sinian Dengying Formation and the Lower Cambrian Longwangmiao Formation, but has not achieved good results in the Ordovician. At present, a number of Wells in the middle Sichuan area show varying degrees of oil and gas in the Lower Ordovician strata, suggesting that the Ordovician strata in this area have the basic conditions for the formation of large-scale oil and gas reservoirs. However, no consensus has been reached on the paleogeographic pattern of Ordovician lithofacies and the distribution of favorable facies zones in this area, and the understanding of reservoir types and reservoir properties is quite different. Therefore, the weak basic research on the geological conditions of reservoir formation has severely restricted the hydrocarbon exploration of the Ordovician in this area. In this paper, the Lower Ordovician lithofacies paleogeography reconstruction and reservoir characteristics analysis are carried out by systematically combing the drilling and field profile data in the central Sichuan area, combined with core observation, thin section identification and reservoir analysis, and finally the Ordovician oil and gas accumulation model is established. The results show that the lithofacies paleogeography distribution of the Lower Ordovician Tongzi-Honghuayuanstage in the central Sichuan area is from the paleo-uplift to the east in the order of platform tidal flat to platform shoal to limited platform. The Lower Ordovician reservoir types in the middle Sichuan area include karst reservoir and dolomite reservoir, among which the karst reservoir is heavily filled and the reservoir performance is limited. The Ordovician reservoir-forming model in the middle Sichuan area reveals a new exploration model of dolomite superimposed bedding under karst in the epicontinental platform, which provides important geological basis for the new breakthrough of Ordovician oil and gas exploration.

New constraints on the central mass contents of Omega Centauri from combined stellar kinematics and pulsar timing

We performed a combined analysis of stellar kinematics with line-of-sight accelerations of millisecond pulsars (MSPs) to probe the mass content of Omega Centauri (OC ). Our mass model includes the stellar mass distribution, a more concentrated mass component linked to the observed MSP population, a generic cluster of stellar remnants (assumed to be more concentrated than the stars and MSPs), and an intermediate-mass black hole (IMBH), allowing us to determine which of these is statistically preferred to account for these observations. We mass-modeled OC using the package GravSphere to solve the Jeans equations, including constraints in the form of proper motions, line-of-sight velocities, the surface density profile of the stars, the spatial distribution of MSPs, and the recently measured line-of-sight accelerations of a subset of these MSPs, self-consistently modeling their intrinsic spin-down. We explore the impact of different assumed centers of OC on our results and we infer the posterior distributions of the model parameters from the combined likelihood using the nested sampling package dynesty Our analysis favors an extended central mass of $ over an IMBH, setting a 3sigma upper limit on the IMBH mass of $6 We find that pulsar timing observations are an important additional constraint, favoring a central mass distribution that is $ 20<!PCT!>$ more massive and extended than implied by models that are constrained by the stellar kinematics alone. Finally, we find a 3sigma confidence level (CL) upper bound of $6 on the total mass traced by the MSPs, with the density profile following $ p (r) star (r)^ with $ 0.3,$ where $ star (r)$ is the stellar mass density and $ is the stellar velocity dispersion profile. This favors models in which MSPs form via stellar encounters, as in the leading paradigm whereby MSPs are the progeny of low-mass X-ray binaries. Our analysis demonstrates how combining stellar kinematics with MSP accelerations produces new constraints on mass models, shedding light on the presence or absence of IMBHs at the centers of globular clusters. Further, we provide the first validation of its kind where MSP positions are linked to their place of formation in globular clusters, which is in excellent agreement with the expectations of stellar encounter models of MSP formation. This sets a promising precedent amid the rapid growth in the number of observations and discoveries currently taking place in this field.

Improvement of Sustainable Economic Mechanisms for the Formation of Tourist and Recreational Clusters in the Khorezm Region of the Republic of Uzbekistan

Objective: The study aims to create scientific and practical recommendations and proposals for enhancing the mechanisms of forming tourist and recreational clusters through innovative approaches, specifically tailored for application in the Republic of Uzbekistan. Method: Research was conducted through case studies, literature reviews, and data collection, focusing on identifying key factors in cluster formation, analyzing competitive tourism clusters, and developing strategies for the Khorezm region. Results and Discussion: The research focuses on enhancing the formation of tourist and recreational clusters in the Khorezm region of Uzbekistan through innovative approaches. It proposes organizing tourist complexes at various development levels, leveraging ecotourism and cultural-pilgrimage clusters such as "Khiva Smart," and developing zones like the "Amu Darya Ecological Zone." The study highlights the importance of public-private partnerships and the tourism potential of the region, with forecast values for growth in tourist flows between 2024-2027. Research Implications: Theoretically, the research introduces an innovative cluster formation model that can serve as a framework for future studies on tourism development, especially in regions with underutilized recreational potential. The findings also highlight the importance of seasonality in cluster planning, ensuring optimal resource allocation and long-term sustainability.

Novel pseudo-hexagonal montmorillonite model and microsecond MD simulations of hydrate formation in mixed clay sediments with surface defects.

Both CH4 hydrate accumulation and hydrate-based CO2 sequestration involve hydrate formation in mixed clay sediments. The development of realistic clay models and a nanoscale understanding of hydrate formation in mixed clay sediments are crucial for energy recovery and carbon sequestration. Here, we propose a novel molecular model of pseudo-hexagonal montmorillonite nanoparticles. The stress-strain curves of tension, compression, and shear of pseudo-hexagonal montmorillonite nanoparticles exhibit linear characteristics, with tension, compression, and shear moduli of ∼435, 410, and 137GPa, respectively. We perform microsecond molecular dynamics simulations to study CH4 and CH4/CO2 hydrate formation in montmorillonite-illite mixed clay sediments with surface defects. The results indicate that hydrate formation in mixed clay sediments is significantly influenced by the presence of clay defects. CH4 and CH4/CO2 mixed hydrates are challenging to form at the junction between the inside and outside clay defects. CH4 and CH4/CO2 mixed hydrates exhibit a preference for forming outside the clay defects rather than inside the clay defects. Some CH4 and CO2 molecules from the inside clay defect migrate to the outside clay defect, thereby promoting CH4 and CH4/CO2 mixed hydrate formation outside the clay defects. This molecular insight advances the development of clay particle models and expands an understanding of natural gas hydrate accumulation and hydrate-based CO2 sequestration.

Follow-up supportive policies and risk perception influence livelihood adaptation of anti-poverty relocated households in ethnic mountains of southwest China

The poverty alleviation relocation program (PAR) is a milestone project in breaking spatial poverty traps in ethnic mountainous regions and provides a key solution for eradicating global absolute poverty. As direct participants in the restructuring of environmental and livelihood systems, the livelihood adaptation of relocated households is fundamental to the sustainable development of human-land systems in resettlement sites and the consolidation of the success of poverty alleviation. This research constructs an adaptive integration analysis framework of “external disturbance-adaptation process-adaptation outcome”, by utilizing questionnaire data from relocated households in the Liangshan Yi minority area of Southwest China, and employing a formative structural equation model to investigate the transmission mechanisms and heterogeneous effects of PAR on livelihood adaptation across different resettlement characteristics. The results indicate that: (1) External disturbance of PAR facilitates positive adaptation outcomes, with follow-up supportive policy as the most significant determinant, which contributes directly to adaptation outcomes and indirectly through improved learning and self-organization capacity. Conversely, risk perception has a negative impact on adaptation outcomes and further exacerbates adverse impacts by reducing buffering capacity. (2) The pathways influencing subjective and objective adaptation outcomes demonstrate heterogeneity. PAR has a positive impact on subjective adaptation, but a non-significant effect on objective adaptation, self-organization capacity and buffering capacity are the most important direct drivers and mediating variables affecting both, respectively. (3) Resettlement characteristics exert a moderating effect on livelihood adaptation. The positive effect of follow-up supportive policy on learning capacity and the marginal contribution of learning capacity to adaptative strategies being greater in mid-to-long-term resettlements. Buffering capacity of village resettlements and subjective adaptation of town resettlements are more beneficial from follow-up supportive policy.

The impact of different effective models for star formation on the properties of simulated Milky Way-sized galaxies

Abstract Hydrodynamical cosmological simulations of galaxy formation such as
IllustrisTNG or Auriga have shown considerable success in approximately matching
many galaxy properties, but their treatment of the star-forming interstellar medium (ISM)
has relied on heuristic sub-grid models. However, recent high-resolution simulations of
the ISM that directly resolve the regulation of star formation suggest different mean rela-
tions for the dependences of pressure and star formation rate on the average gas density.
In this study, we adopt such a modern, physically grounded parameterisation inspired by
the TIGRESS small-scale simulations. We dub this model TEQS and use it for a detailed
comparative analysis of the formation and evolution of Milky Way-sized galaxy when
compared with the widely used TNG model. By employing high-resolution simulations
in tall box setups, we first investigate the structural differences expected for these two
models when applied to different self-gravitating gas surface densities. Our results indi-
cate that TEQS produces considerably thinner gaseous layers and can be expected to form
stellar distributions with smaller scale height than TNG, especially at higher surface den-
sity. To test whether this induces systematic structural differences in cosmological galaxy
formation simulations, we carry out zoom-in simulations of 12 galaxies taken from the
set of Milky Way-sized galaxies that have been studied in the Auriga project. Comparing
results for these galaxies shows that disk galaxies formed with the TEQS model have on
average very similar stellar mass but are more concentrated in their central regions and ex-
hibit smaller stellar radii compared to those formed with the TNG model. The differences
in the scale heights of the formed stellar disks are only marginal, however, suggesting that
other factors for setting the thickness of the disk are more important than the applied ISM
equation-of-state model. Overall, the predicted galaxy structure is quite similar for TNG
and TEQS despite significant differences in the employed star formation law, demonstrat-
ing that feedback processes are more important in regulating the stellar mass than the
precise star formation law itself.

Comparing E-MOSAICS predictions of high-redshift proto-globular clusters with JWST observations in lensed galaxies

ABSTRACT High-resolution imaging and strong gravitational lensing of high-redshift galaxies have enabled the detection of compact sources with properties similar to nearby massive star clusters. Often found to be very young, these sources may be globular clusters detected in their earliest stages. In this work, we compare predictions of high-redshift ($z \sim 1$–10) star cluster properties from the E-MOSAICS simulation of galaxy and star cluster formation with those of the star cluster candidates in strongly lensed galaxies from JWST and Hubble Space Telescope (HST) imaging. We select galaxies in the simulation that match the luminosities of the majority of lensed galaxies with star cluster candidates observed with JWST. We find that the luminosities, ages, and masses of the brightest star cluster candidates in the high-redshift galaxies are consistent with the E-MOSAICS model. In particular, the brightest cluster ages are in excellent agreement. The results suggest that star clusters in both low- and high-redshift galaxies may form via common mechanisms. However, the brightest clusters in the lensed galaxies tend to be $\approx 1$–$1.5 \, \rm {mag}$ brighter and $\approx 0.5$ dex more massive than the median E-MOSAICS predictions. We discuss the large number of effects that could explain the discrepancy, including simulation and observational limitations, stellar population models, cluster detection biases, and nuclear star clusters. Understanding these limitations would enable stronger tests of globular cluster formation models.

A Census of Dwarf Galaxy Satellites around LMC-mass Galaxy NGC 2403* * This research is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

We present the first comprehensive census of the satellite population around a Large Magellanic Cloud stellar-mass galaxy, as part of the Magellanic Analog Dwarf Companions and Stellar Halos (MADCASH) survey. We have surveyed NGC 2403 (D = 3.0 Mpc) with the Subaru/Hyper Suprime-Cam imager out to a projected radius of 90 kpc (with partial coverage extending out to ∼110 kpc, or ∼80% of the virial radius of NGC 2403), resolving stars in the uppermost ∼2.5 mag of its red giant branch. By looking for stellar overdensities in the red giant branch spatial density map, we identify 149 satellite candidates, of which only the previously discovered MADCASH J074238+65201-dw is a bona fide dwarf, together with the more massive and disrupting satellite DDO 44. We carefully assess the completeness of our search via injection of artificial dwarf galaxies into the images, finding that we are reliably sensitive to candidates down to M V ∼ −7.5 mag (and somewhat sensitive to even fainter satellites). A comparison of the satellite luminosity function of NGC 2403 down to this magnitude limit to theoretical expectations shows overall good agreement. This is the first of a full sample of 11 Magellanic Cloud–mass host galaxies we will analyze, creating a statistical sample that will provide the first quantitative constraints on hierarchical models of galaxy formation around low-mass hosts.

Dependence of pollutant emissions on operating parameters of gas pumping units at subzero temperatures

Abstract Pollutant emissions from gas-fired equipment are determined by the combustion parameters and the design of the units and burners. In addition to the design, NOX and CO emissions significantly depend on environmental parameters, including air temperature. The article examines the features of pollutant formation processes during operation of gas turbine units of various designs and configurations: both stationary units such as the GTK-10M designed for main gas transportation and converted marine engines DR-59L used as a drive for gas pumping units at subzero outside air temperatures. The operation of hot water boilers as part of a gas heating unit was also investigated. The studies were conducted to develop mathematical models of pollutant formation to create a continuous calculation control system that will allow for high-precision determination and prediction of limit values for NOX and CO emissions and minimize the impact of emissions on the environment.

On the Stellar Disk Vertical Scale Height of Edge-on Galaxies from S4G

Disk galaxies viewed as thin planar structures resulting from the conservation of angular momentum of an initially rotating pregalactic cloud allow merely a first-order model of galaxy formation, but the presence of vertically extended structures has allowed us to gather a deeper understanding of the richness in astrophysical processes (e.g., minor mergers, secular evolution) that ultimately results in the observed diversity in disk galaxies and their vertical extensions. We measure the stellar disk scale height of 46 edge-on spiral galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G) project. This paper aims to investigate the radial variation of the stellar disk vertical scale height and the existence of the so-called thick disk component in our sample. The measurements were made using one-, two-, and three-dimensional profile fitting techniques using simple models. We found that two-thirds of our sample show the presence of a thick disk, suggesting that these galaxies have been accreting gaseous material from their surroundings. We found an average thick-to-thin disk scale height ratio of 2.65, which is in good agreement with previous studies. Our findings also support the disk flaring model, which suggests that the vertical scale height increases with radius. We further found good correlations between the scale height h z and the scale length and between h z and the optical de Vaucouleurs radius R 25.

Uncertainty Quantification in Reduced‐Order Gas‐Phase Atmospheric Chemistry Modeling Using Ensemble SINDy

AbstractUncertainty quantification during atmospheric chemistry modeling is computationally expensive as it typically requires a large number of simulations using complex models. As such, large‐scale modeling is typically performed with simplified chemical mechanisms for computational tractability. Here, we describe a probabilistic surrogate modeling method using principal components analysis (PCA) and Ensemble Sparse Identification of Nonlinear Dynamics (E‐SINDy) to both automatically simplify a gas‐phase chemistry mechanism and to quantify the uncertainty introduced when doing so. We demonstrate the application of this method on a small photochemical box model for ozone formation. With 100 ensemble members, the calibration ‐squared value is 0.86 among the three latent species on average and 0.98 for ozone, demonstrating that predicted model uncertainty aligns well with actual model error. In addition to uncertainty quantification, this probabilistic method also improves accuracy as compared to an equivalent deterministic version, by 64% for the ensemble prediction mean or 45% for deterministic prediction by the best‐performing single ensemble member. Overall, the ozone testing root mean square error (RMSE) is 20% of its root mean square (RMS) concentration. Although our probabilistic ensemble simulation ends up being slower than the reference model it emulates, we hypothesize that use of a more complex reference model in future work will result in additional opportunities for acceleration. Versions of this approach applied to full‐scale chemical mechanisms may result in improved uncertainty quantification in models of atmospheric composition, leading to enhanced atmospheric understanding and improved support for air quality control and regulation.

A Novel Image Formation Model for Descattering.

In the field of image descattering, the image formation models employed for restoration approaches are often simplified. In these models, scattering distribution is uniform in homogeneous media when transmission is fixed. Through specifically designed experiments, we discover that scattering exhibits non-uniform characteristics even in homogeneous media. Neglecting non-uniform scattering in these models limits their accuracy in representing scattering distribution, resulting in existing image descattering approaches inadequate. To tackle these issues, this paper proposes a novel image formation model for image descattering, considering more physical parameters, such as zenith angle, azimuth angle, scattering phase function, and camera focal length. Our model describes the light transfer process in scattering media more accurately. For image descattering, we introduce corresponding algorithms for parameter estimation in our model and simultaneous restoration from degraded images. Experimental evaluations demonstrate the effectiveness of our proposed model in various tasks, including physical parameter estimation, pure-scattering removal, image dehazing, and underwater image restoration. In terms of calculating parameters, our results are close to the real values; in terms of underwater image restoration, our work outperforms the state-of-art methods; in terms of image dehazing, our work promotes the performance of existing methods by replacing previous models with our model.

Exoplanets across galactic stellar populations with PLATO

Context. The vast majority of exoplanet discoveries to date have occurred around stars in the solar neighbourhood, with chemical compositions comparable to that of the Sun. However, models suggest that planetary systems in different Galactic environments, with varying dynamical histories and chemical abundances, may exhibit distinct characteristics, which can help improve our understanding of planet formation processes. Aims. This study aims to assess the potential of the upcoming PLATO mission to investigate exoplanet populations around stars in diverse Galactic environments, specifically focusing on the Milky Way thin disk, thick disk, and stellar halo. We aim to quantify PLATO’s ability to detect planets in each environment and determine how these observations could constrain planet formation models. Methods. Beginning with the all-sky PLATO Input Catalogue, we kinematically classified the 2.4 million FGK stars into their respective Galactic components. For the sub-sample of stars in the long-observation LOPS2 and LOPN1 PLATO fields, we estimated planet occurrence rates using the New Generation Planet Population Synthesis dataset. Combining these estimates with a PLATO detection efficiency model, we predicted the expected planet yields for each Galactic environment during a nominal 2+2 year mission. Results. Based on our analysis, PLATO is likely to detect at least 400 exoplanets around the α-enriched thick disk stars. The majority of those planets are expected to be super-Earths and sub-Neptunes with radii between 2 and 10 R⊕ and orbital periods between 2 and 50 days, which is ideal for studying the link between the radius valley and stellar chemistry. For the metal-poor halo, PLATO is likely to detect between 1 and 80 planets with periods between 10 and 50 days, depending on the potential existence of a metallicity threshold for planet formation. The PLATO fields contain more than 3400 potential target stars with [Fe/H] < −0.6, which will help improve our understanding of planets around metal-poor stars. We identified a specific target list of 47 (kinematically classified) halo stars in the high-priority, high-signal-to-noise PLATO P1 sample, offering prime opportunities in the search for planets in metal-poor environments. Conclusions. PLATO’s unique capabilities and large field of view position it as a valuable tool for studying planet formation across the diverse Galactic environments of the Milky Way. By probing exoplanet populations around stars with a varying chemical composition, PLATO will provide helpful insights into the connection between stellar chemistry and planet formation.

Bayesian Belief Networks: Redefining wholesale electricity price modelling in high penetration non-firm renewable generation power systems

The transition of electricity generation from firm to non-firm renewable generation is driving changes in wholesale electricity price dynamics that are increasingly challenging to model due to the stochastic nature of wind and solar as the primary energy source. Robust pricing models are essential for optimising financial performance in liberalised electricity markets. The novelty of this paper is the application of Bayesian Belief Networks in the modelling of wholesale electricity price formation, specifically in power systems with a high penetration of non-firm renewable generation. This paper links the mathematical Bayesian representation to established statistical and computational approaches using a functional supply-side wholesale electricity market pricing model. In addition, the paper introduces a novel validation method employing volatility analysis to assess the case study's performance.The case study revealed that when the proportion of stochastic generation was ≥40 % penetration in a trading interval, the Bayesian Belief Network model's accuracy considerably outperformed the benchmark model with a Mean Absolute Scale Error of 1.43 compared to 1.63 in those intervals. Finally, the volatility analysis results challenged the prevailing notion of a positive causal relationship between non-firm renewable penetration and price volatility.

The formation of supermassive black holes from Population III.1 seeds. III. Galaxy evolution and black hole growth from semi-analytic modelling

ABSTRACT We present an implementation of Pop III.1 seeding of supermassive black holes (SMBHs) in a theoretical model of galaxy formation and evolution to assess the growth of the SMBH population and the properties of the host galaxies. The model of Pop III.1 seeding involves SMBH formation at redshifts $z\gtrsim 20$ in dark matter minihaloes that are isolated from external radiative feedback, parametrized by isolation distance $d_{\rm iso}$. Within a standard $\Lambda$CDM cosmology, we generate dark matter haloes using the code pinocchio and seed them according to the Pop III.1 scenario, exploring values of $d_{\rm iso}$ from 50 to 100 kpc (proper distance). We consider two alternative cases of SMBH seeding: a halo mass threshold model in which all haloes $\gt 7\times 10^{10}\,\rm M_\odot$ are seeded with $\sim 10^5\,\rm M_\odot$ black holes; an all light seed model in which all haloes are seeded with low, stellar mass black holes. We follow the redshift evolution of the haloes, populating them with galaxies using the GAlaxy Evolution and Assembly theoretical model of galaxy formation, including accretion on SMBHs and related feedback processes. Here we present predictions for the properties of galaxy populations, focusing on stellar masses, star formation rates, and black hole masses. The local, $z\sim 0$ metrics of occupation fraction as a function of the galaxy stellar mass, galaxy stellar mass function, and black hole mass function all suggest a constraint of $d_{\rm iso}\lt 75\:$ kpc. We discuss the implications of this result for the Pop III.1 seeding mechanism.