The Logic Theorist (LT), created by Allen Newell, J. C. Shaw, and Herbert Simon in 1955-1956, is widely regarded as the first artificial intelligence program. While the original conceptual model was described in 1956, it underwent several iterations as the underlying Information Processing Language (IPL) evolved. Here I describe the construction of a new IPL-V interpreter, written in Common Lisp, and the faithful reanimation of the Logic Theorist from code transcribed directly from Stefferud's 1963 RAND technical report. Stefferud's version represents a pedagogical re-coding of the original heuristic logic into the standardized IPL-V. The reanimated LT successfully proves 16 of 23 attempted theorems from Chapter 2 of Principia Mathematica, results that are historically consistent with the original system's behavior within its search limits. To the author's knowledge, this is the first successful execution of the original Logic Theorist code in over half a century.
Daisuke Taniguchi, Patrick de Laverny, Alejandra Recio-Blanco
et al.
[Abbreviated] Context. Solar twins, stars whose stellar parameters (Teff, log g, and [M/H]) are very close to the Solar ones, offer a unique opportunity to investigate Galactic archaeology with very high accuracy and precision. However, most previous catalogs of Solar twins contain only a small number of objects (typically a few tens), and their selection functions are poorly characterized. Aims. We aim at building a large catalog of Solar twins from Gaia DR3 GSP-Spec, providing model-driven, rather than data-driven, stellar parameters including ages, together with a well-characterized selection function. Methods. Using stellar parameters from the Gaia DR3 GSP-Spec catalog, we selected Solar-twin candidates whose parameters lie within +- 200 K in Teff, +- 0.2 in log g, and +- 0.1 dex in [M/H] of the Solar values. Candidates unlikely to be genuine Solar twins were removed using Gaia flags and photometric constraints. We determined accurate ages for individual twins with a Bayesian isochrone-projection method, considering three combinations of parameters: Teff, [M/H], and either log g, M_G, or M_Ks. We also constructed a mock catalog to characterize the selection function. Results. Our final GSP-Spec Solar-twin catalog contains 6,594 stars. The mock catalog consisting of 75,588 artificial twins well reproduces the main characteristics of the observed catalog, especially for ages determined with M_G or M_Ks. To demonstrate the usefulness of our catalog, we compared chemical abundances [X/Fe] with age. We statistically confirmed the age--[X/Fe] relations for several species (e.g., Al, Si, Ca, and Y), demonstrating that trends previously identified in small but very high-precision samples persist in a much larger, independent sample. Conclusions. Our study bridges small high-precision Solar-twin samples and large data-driven ones, enabling demographic studies of Solar twins.
A commonly-used paradigm to estimate changes in the frequency of past events or the size of populations is to consider the occurrence rate of archaeological/environmental samples found at a site over time. The reliability of such a "dates-as-data" approach is highly dependent upon how the occurrence rates are estimated from the underlying samples, particularly when calendar age information for the samples is obtained from radiocarbon (14C). The most frequently used "14C-dates-as-data" approach of creating Summed Probability Distributions (SPDs) is not statistically valid, or coherent, and can provide highly misleading inference. Here, we provide an alternative method with a rigorous statistical underpinning that also provides valuable additional information on potential changepoints in the rate of events. Furthermore, unlike current SPD alternatives, our summarisation approach does not restrict users to pre-specified, rigid, summary formats (e.g., exponential or logistic growth) but instead flexibly adapts to the dates themselves. Our methodology ensures more reliable "14C-dates-as-data" analyses, allowing us to better assess and identify potential signals present. We model the occurrence of events, each assumed to leave a radiocarbon sample in the archaeological/environmental record, as an inhomogeneous Poisson process. The varying rate of samples over time is then estimated within a fully-Bayesian framework using reversible-jump Markov Chain Monte Carlo (RJ-MCMC). Given a set of radiocarbon samples, we reconstruct how their occurrence rate varies over calendar time and identify if that rate contains statistically-significant changes, i.e., specific times at which the rate of events abruptly changes. We illustrate our method with both a simulation study and a practical example concerning late-Pleistocene megafaunal population changes in Alaska and Yukon.
Evans K. Owusu, Ashley J. Ruiter, Alex J. Kemp
et al.
We recently identified an upturn in [Na/Fe] for the population of Solar-type stars in the Galactic young thick disc ($-0.3 < \mathrm{[Fe/H]} < +0.3$) at super-Solar metallicity in data from the GALactic Archaeology with HERMES (GALAH) survey. In this work, we investigate the origin of this unexplained sodium enrichment ([Na/Fe] $\approx 0$--$0.6$~dex) using the OMEGA$+$ galactic chemical evolution code. We explore the rise of [Na/Fe] using four combinations of nucleosynthetic yields from the literature, considering contributions from core-collapse supernovae, asymptotic giant branch stars, and Type~Ia supernovae. Our analysis focuses on two possible drivers of the Na enhancement: a metallicity-dependent increase in Na production from core-collapse supernovae at super-Solar metallicities, and enrichment from metal-rich AGB stars. We adopt two sets of Type~Ia supernova yields, one assuming exclusively Chandrasekhar-mass explosions and the other assuming only sub-Chandrasekhar-mass explosions. We find that the assumed Type~Ia explosion scenario has little influence on the resulting [Na/Fe] evolution, and that all chemical evolution models tested fail to reproduce the observed Na enrichment in the young thick-disc population at super-Solar metallicity. Our results suggest a possible ``under-pollution effect'' by Type~Ia supernovae -- the dominant producers of iron -- in the Solar-type stellar population of the Galactic disc. These findings provide a step toward understanding the origin of the anomalous sodium enrichment at super-Solar metallicities in the Galactic disc.
Liberty Mlambo, Elhadi Adam, Munyaradzi Davis Shekede
et al.
Understanding the influence of biophysical variables on spatial distribution and seasonal locations of elephants is valuable inter alia in understanding their movement patterns, and the carrying capacity to optimise the conservation of their habitats. Furthermore, understanding elephant distribution in time and space is beneficial for predicting locations for tourist viewing and determining potential areas of human–wildlife conflicts. In this study, we examined the environmental drivers of seasonal variations in elephant ranges and movement using telemetry data. Using the elephant tracking data and biophysical characteristics, the Adaptive-Local Convex Hull (a-LoCoH) and the Maximum Entropy Modelling (MaxEnt) algorithm were adopted to determine their potential locations and distribution in a protected area. The jackknife approach was used to assess the environmental factors influencing seasonal elephant movements based on collar data from ten individual elephants tracked between December 2015 and April 2018. The performance of the elephant distribution models for the two seasons was assessed using the area under the curve from the receiver operating characteristic based on a 30% test holdout data. Results showed that the core a-LoCoH home of elephants was larger in the dry than wet season (Wilcoxon signed-rank test; W = 3, Z = 2.4973, p < 0.012). However, no noticeable differences were observed (Wilcoxon signed-rank test; W = 10, Z = 1.7838, p < 0.07) between the dry and wet season for the total (90%) a-LoCoH ranges. The MaxEnt modelling results showed that distance to the artificial water holes was the most influential variable in predicting the potential elephant spatial distribution in both wet and dry seasons, while the normalised difference vegetation index, a proxy for forage availability, was more influential in the dry season in predicting elephant distribution. The study concludes that seasonal elephant space use is mostly influenced by water availability in both seasons, while forage availability and variability influence elephant distribution more strongly in the dry than wet season. The study provides valuable insight into the biophysical characteristics of elephant home ranges. This is useful for the sustainable management of elephants and their habitats.
Bartholdy, Bjørn Peare, Hasselstrøm, Jørgen B., Sørensen, Lambert K.
et al.
Dental calculus is an excellent source of information on the dietary patterns of past populations, including consumption of plant-based items. The detection of plant-derived residues such as alkaloids and their metabolites in dental calculus provides direct evidence of consumption by individuals within a population. We conducted a study on 41 individuals from Middenbeemster, a 19th century rural Dutch archaeological site. Skeletal and dental analysis was performed to explore potential relationships between pathological lesions and presence of alkaloids. Dental calculus was analysed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-ESI-MS/MS). We were able to detect nicotine, cotinine, caffeine, theophylline, and salicylic acid, suggesting the consumption of tea and coffee and smoking of tobacco on an individual scale, which is also confirmed by historic documentation and identification of pipe notches in the dentition. Nicotine and/or cotinine was present in 56% of individuals with at least one visible pipe notch. There is some influence of skeletal preservation on the detection of alkaloids, with higher quantities of compounds extracted from well-preserved individuals, and we observe a positive relationship between weight of the calculus sample and quantity of detected compounds, as well as between chronic maxillary sinusitis and the presence of multiple alkaloids. There are many limitations that will need to be addressed going forward with this type of analysis; we stress the need for more systematic research on the consumption of alkaloid-containing items and their subsequent concentration and preservation in dental calculus, in addition to how mode of consumption may affect concentrations in the dentition. Despite the limitations, this preliminary study illustrates many benefits of using calculus to target a variety of compounds that could have been consumed as medicine or diet. This method allows us to directly address specific individuals, which can be especially useful in individuals that are not always well-documented in historic documentation, such as rural populations, and especially children and women.
Context. Understanding the Milky Way's formation and evolution across cosmic epochs necessitates precise stellar age determination across all Galactic components. Recent advancements in asteroseismology, spectroscopy, stellar modelling, and machine learning, coupled with all-sky surveys, now offer highly reliable stellar age estimates. Aims. This study aims to furnish accurate age assessments for the Main Red Star Sample within the APOGEE DR17 catalogue. Leveraging asteroseismic age constraints, we employ machine learning to achieve this goal. Methods. We explore optimal non-asteroseismic stellar parameters, including T$_{eff}$, L, [CI/N], [Mg/Ce], [$α$/Fe], U(LSR) velocity, and 'Z' vertical height from the Galactic plane, to predict ages via categorical gradient boost decision trees. Training merges samples from the TESS Southern Continuous Viewing Zone and Second APOKASC catalogue to mitigate data shifts, enhancing prediction reliability. Validation employs an independent dataset from the K2 Galactic Archaeology Program. Results. Our model yields a median fractional age error of 20.8%, with a prediction variance of 4.77%. Median fractional errors for stars older than 3 Gyr range from 7% to 23%, from 1 to 3 Gyr range from 26% to 28%, and for stars younger than 1 Gyr, it's 43%. Applicable to 125,445 stars in the APOGEE DR17 Main Red Star Sample, our analysis confirms previous findings on the young Galactic disc's flaring and reveals an age gradient among the youngest Galactic plane stars. Additionally, we identify two groups of metal-poor ([Fe/H] < -1 dex) young stars (Age < 2 Gyr) exhibiting similar chemical abundances and halo kinematics, likely remnants of the predicted third gas infall episode (~2.7 Gyr ago).
Lidia La Mendola, Matteo Accardi, Fabrizio Agnello
et al.
This paper presents the path of knowledge developed for assessing the structural safety of the Norman-age Pisan Tower, which is mostly incorporated into the Royal Palace in Palermo, Italy. Historical, geomatic, and mechanical investigations were conducted and the most relevant results are herein collected and presented. The research path was addressed to specific tasks: identification of the building, geometric surveys, recognition of the sequence of phases of building transformation, detection of the components of the load-bearing structure, structural diagnostic surveys, and investigation of the subsoil and foundations. The explicit vulnerabilities found were mostly confined to the Piazzi library floor, while implicit vulnerabilities were identified in the presence of false walls and in high loads and fillings on the vaults of the last levels. The results of the analyses allowed the individuation of the confidence factors to use in structural analysis models aimed at the assessment of the seismic safety of the building.
Daniel R. Weisz, Alessandro Savino, Andrew E. Dolphin
Using color-magnitude diagrams from deep archival Hubble Space Telescope imaging, we self-consistently measure the star formation history of Eridanus II (Eri II), the lowest-mass galaxy ($M_{\star}(z=0) \sim 10^5 M_{\odot}$) known to host a globular cluster (GC), and the age, mass, and metallicity of its GC. The GC ($\sim13.2\pm0.4$ Gyr, $\langle$[Fe/H]$\rangle = -2.75\pm0.2$ dex) and field (mean age $\sim13.5\pm0.3$ Gyr, $\langle$[Fe/H]$\rangle = -2.6\pm0.15$ dex) have similar ages and metallicities. Both are reionization-era relics that formed before the peak of cosmic star and GC formation ($z\sim2-4$). The ancient star formation properties of Eri II are not extreme and appear similar to $z=0$ dwarf galaxies. We find that the GC was $\lesssim4$ times more massive at birth than today and was $\sim$10% of the galaxy's stellar mass at birth. At formation, we estimate that the progenitor of Eri II and its GC had $M_{\rm UV} \sim -7$ to $-12$, making it one of the most common type of galaxy in the early Universe, though it is fainter than direct detection limits, absent gravitational lensing. Archaeological studies of GCs in nearby low-mass galaxies may be the only way to constrain GC formation in such low-mass systems. We discuss the strengths and limitations in comparing archaeological and high redshift studies of cluster formation, including challenges stemming from the Hubble Tension, which introduces uncertainties into the mapping between age and redshift.
Синика Виталий Степанович, Разумов Сергей Николаевич, Лысенко Сергей Дмитриевич
et al.
В статье впервые публикуются и анализируются материалы, полученные при исследовании венгерского погребения 3 кургана 7 группы «ДОТ» у с.Глиное Слободзейского района на левобережье Нижнего Днестра. Захоронение было совершено в прямоугольной яме возле юго-восточной полы насыпи. Костяк лежал в вытянутом положении на спине, головой на запад-юго-запад. У левого плеча находилась левая плечевая кость овцы. Подобный обряд зафиксирован не только в венгерских могилах Северного Причерноморья, но и восточнее – в Подонье, в Поволжье и на Урале. В качестве жертвенных животных венгры использовали не только овец, но и лошадей, а также крупный рогатый скот. В ногах была поставлена деревянная колода. У левого колена был найден железный нож, у левой стопы – железная пластина. Поверх левого крыла таза лежали две серединные костяные накладки от лука. На правой лучевой кости располагались остатки колчана в виде пяти железных наконечников стрел и железного шила. Под правым запястьем, у крыла таза, зафиксированы фрагменты железного кресала и кресальный кремень. Аналогии наконечникам стрел, а также радиоуглеродные даты позволяют датировать захоронение концом IX – первой половиной Xвв. Это погребение, вместе с ранее исследованными на левобережье Нижнего Днестра венгерскими могилами, позволяет фиксировать пребывание венгров в регионе с середины IX по середину Xвв.
Matthew Raymond Gent, Philipp Eitner, Aldo Serenelli
et al.
Context. The presence of [$α$/Fe]-[Fe/H] bi-modality in the Milky Way disc has animated the Galactic archaeology community since more than two decades. Aims. Our goal is to investigate the chemical, temporal, and kinematical structure of the Galactic discs using abundances, kinematics, and ages derived self-consistently with the new Bayesian framework SAPP. Methods. We employ the public Gaia-ESO spectra, as well as Gaia EDR3 astrometry and photometry. Stellar parameters and chemical abundances are determined for 13 426 stars using NLTE models of synthetic spectra. Ages are derived for a sub-sample of 2 898 stars, including subgiants and main-sequence stars. The sample probes a large range of Galactocentric radii, $\sim$ 3 to 12 kpc, and extends out of the disc plane to $\pm$ 2 kpc. Results. Our new data confirm the known bi-modality in the [Fe/H] - [$α$/Fe] space, which is often viewed as the manifestation of the chemical thin and thick discs. The over-densities significantly overlap in metallicity, age, and kinematics, and none of these is a sufficient criterion for distinguishing between the two disc populations. Different from previous studies, we find that the $α$-poor disc population has a very extended [Fe/H] distribution and contains $\sim$ 20$\%$ old stars with ages of up to $\sim$ 11 Gyr. Conclusions. Our results suggest that the Galactic thin disc was in place early, at look-back times corresponding to redshifts z $\sim$ 2 or more. At ages $\sim$ 9 to 11 Gyr, the two disc structures shared a period of co-evolution. Our data can be understood within the clumpy disc formation scenario that does not require a pre-existing thick disc to initiate a formation of the thin disc. We anticipate that a similar evolution can be realised in cosmological simulations of galaxy formation.
Abstract In the 21st century, advances in computer science have impacted archaeology, most recently in the development of automated algorithms. Like most technology, these methods have been the source of ongoing debate, particularly in their utility for archaeology. Here, I focus on a contribution of automation and machine learning in archaeology that is often overlooked: the ability of computer algorithms to codify unambiguous, semantically consistent definitions. Archaeology has long struggled with establishing consistent characterizations of the phenomena it studies. As such, I argue that the procedures used for automated methods are useful for archaeologists – even outside of automated analyses – by allowing for the creation of consistent definitions which permit for reproducible research designs.
The Eastern Anatolia region, a high plateau, is exceptionally rich in paintings on rocks. Rock paintings in Ardahan, Kars, Erzurum, Erzincan, and Van-Hakkari mountainous region constitute a large part of this wealth. The technique of line, engraving, carving, and pecking was generally used in rock paintings drawn on andesitic and basalt stones in the region. The motifs encountered in rock painting areas are human (shaman), horse, bull - ox - cow, deer, wolf, dog, and sheep - ram - mountain goat. Furthermore, scenes of hunting and war, ceremonial and geometric scenes, and celestial shapes are among the covered themes. Sixteen rock painting areas were identified in the Northeast Anatolian region. Nine centers were examined in the study; Çıldır Başköy, Borluk Valley/Azat village, Camuşlu, Digor/Dolaylı, Geyiklitepe, Kurbanağa, Dilli Valley, Cunni Cave, and Şenkaya Kaynak village are rock paintings. There are more than 368 figures in these paintings, of which 119 are mountain goat figures. In the study, the morphology of the mountain goat motif in the related rock painting areas was examined, and its symbolic meaning and place in the hunting ritual and the possible cosmic world were analyzed.
Conservation policy in the giant Galpagos tortoise, an iconic endangered animal, has been assisted by genetic markers for 15 years: a dozen loci have been used to delineate thirteen (sub)species, between which hybridization is prevented. Here, comparative reanalysis of a previously published NGS data set reveals a conflict with traditional markers. Genetic diversity and population substructure in the giant Galpagos tortoise are found to be particularly low, questioning the genetic relevance of current conservation practices. Further examination of giant Galapagos tortoise population genomics is critically needed.
Este artículo explica cómo se han desarrollado los estudios alrededor de la antropología de las élites en el Ecuador. Argumenta que en aquellos existe una fuerte crítica frente a las burguesías y esencialismos indígenas. Adicionalmente, dichos estudios, se valen de conceptos antropológicos como el parentesco, símbolos, habitus para analizar la conformación de familias burguesas y su permanencia en la sociedad. Además, se exponen propuestas políticas basadas en la crítica a la desigualdad de clases sociales y la indignación como motivo.
Daichi Kashino, Simon J. Lilly, Alvio Renzini
et al.
We measure the relationship between stellar mass and stellar metallicity, the stellar mass--metallicity relation (MZR), for 1336 star-forming galaxies at $1.6\le z\le3.0$ (<z>=2.2) using rest-frame far-ultraviolet spectra from the zCOSMOS-deep survey. High signal-to-noise composite spectra containing stellar absorption features are fit with population synthesis model spectra of a range of metallicity. We find stellar metallicities, which mostly reflect iron abundances, scaling as $(Z_{Fe,\ast}/Z_{Fe,\odot})=-(0.81\pm0.01)+(0.32+0.03)\log(M_\ast/10^{10}M_\odot)$ across the mass range of $10^9\lesssim M_\ast/M_\odot\lesssim10^{11}$, being $\approx6\times$ lower than seen locally at the same masses. The instantaneous oxygen-to-iron ratio ($α$-enhancement) inferred using the gas-phase oxygen MZRs, is on average found to be [O/Fe]$\approx0.47$, being higher than the local [O/Fe]$\approx0$. The observed changes in [O/Fe] and [Fe/H] are reproduced in simple flow-through gas-regulator models with steady star-formation histories (SFHs) that follow the evolving main sequence. Our models show that the [O/Fe] is determined almost entirely by the instantaneous specific star formation rate alone while being independent of the SFHs, mass, and the gas-regulation characteristics of the systems. We find that the locations of $\sim10^{10}M_\odot$ galaxies at z~2 in the [O/Fe]--metallicity planes are in remarkable agreement with the sequence of low-metallicity thick-disk stars in our Galaxy. This manifests a beautiful concordance between the results of Galactic archaeology and observations of high-redshift Milky Way progenitors. However, there remains a question of how and when the old metal-rich, low-$α$/Fe stars seen in the bulge had formed by z~2 because such a stellar population is not seen in our data and difficult to explain in the context of our models.
ABSTRACT The use of archaeological survey data for evaluation of landscape dynamics has commonly been concerned with the distribution of settlements and changes in number of recorded sites over time. Here we present a new quantitative approach to survey-based legacy data, which allows further assessments of the spatial configuration of possible land-use areas. Utilizing data from an intensive archaeological survey in the Berbati-Limnes area, Greece, we demonstrate how GIS-based kernel density estimations (KDE) can be used to produce cluster-based density surfaces that may be linked to past land-use strategies. By relating density surfaces to elevation and slope, it is also possible to quantify shifts in the use of specific environments on a regional scale, allowing us to model and visualize land-use dynamics over time. In this respect, the approach provides more multifaceted information to be drawn from archaeological legacy data, providing an extended platform for research on human-environment interactions.