Hasil untuk "Archaeology"

Richard Coll Josifov, Luc Devroye, Gabor Lugosi

We investigate the behaviour of five classical centrality measures--Jordan, rumor, betweenness, degree, and closeness centralities--in the setting of uniform random recursive trees. Motivated by applications in network archaeology, we focus on two fundamental questions: (i) the birth index (time of arrival) of the most central vertex, and (ii) the relative centrality of the root. We quantify the probability that the root is the most central vertex, analyze its expected rank under each centrality measure, and determine the expected birth index of a central vertex. In addition, we characterize the typical size of the set of top-ranked vertices that contains the root with high probability. Finally, for each centrality notion, we study the persistence properties of the center and the asymptotic behaviour of the root's rank.

Zhongyuan Zhang, Alexander P Ji, Vinicius M Placco et al.

Massive Population III stars are currently not observed, but their initial mass function (IMF) can be inferred through stellar archaeology: fitting core-collapse supernova yield models to elemental abundances of low-mass, long-lived metal-poor stars. While prior work demonstrates that yield fitting can recover progenitor properties, it remains unclear which measured elements most control mass recovery quality and what level of IMF precision is achievable for a measured element set. We perform a systematic study of element importance for progenitor mass recovery. Using the Heger & Woosley (2010) yield grid, we generate mock observations, fit the initial mass, and evaluate the typical performance on the fractional mass recovery. Add/remove-one-element experiments and comparisons among different baseline element sets are used to rank elements by importance. We find that the most important elements for accurate mass recovery are C, N, Na, and K, with O, Al, Co, and Ni consistently improving performance when available. Overall, with currently measurable elements from high-resolution spectroscopy, stellar archaeology can deliver practical Population III IMF constraints assuming the core-collapse supernova yield models provide a good representation of stellar evolution in the early universe.

Roxana Jaramillo España

Jonathan Shepard

Martin Hanik, Esfandiar Nava-Yazdani, Christoph von Tycowicz

For decades, de Casteljau's algorithm has been used as a fundamental building block in curve and surface design and has found a wide range of applications in fields such as scientific computing, and discrete geometry to name but a few. With increasing interest in nonlinear data science, its constructive approach has been shown to provide a principled way to generalize parametric smooth curves to manifolds. These curves have found remarkable new applications in the analysis of parameter-dependent, geometric data. This article provides a survey of the recent theoretical developments in this exciting area as well as its applications in fields such as geometric morphometrics and longitudinal data analysis in medicine, archaeology, and meteorology.

Noa Keshet, Ehud Behar, Timothy R. Kallman

Supernovae are responsible for the elemental enrichment of the galaxy and some are postulated to leave behind a black hole. In a stellar binary system the supernova pollutes its companion, and the black hole can accrete back its own debris and emit X-rays. In this sequence of events, which is only poorly understood, winds are ejected, and observed through X-ray absorption lines. Measuring abundances of elements in the wind can lead to inferences about the historical explosion and possibly identify the long-gone progenitor of the compact object. Here, we re-analyze the uniquely rich X-ray spectrum of the 2005 outburst of GRO J1655-40. We reconstruct the absorption measure distribution (AMD) of the wind, and find that it increases sharply with ionization from H-like O up to H-like Ca, and then flattens out. The AMD is then used to measure relative abundances of 18 different elements. The present abundances are in partial agreement with a previous work with discrepancies mostly for low-Z elements. The overabundance of odd-Z elements hints at a high-metallicity, high-mass ($\simeq25\,M_\odot$) progenitor. Interestingly, the abundances are different from those measured in the companion atmosphere, indicating that the wind entrains lingering ambient supernova debris. This can be expected since the current total stellar mass of the binary ($<10\,M_\odot$) is much less than the progenitor mass.

Maria Rah, Manolya Yatman, Ali Taani et al.

The Milky Way is a spiral galaxy comprising three main components: the Bulge, the Disk, and the Halo. Of particular interest is the Galactic disk, which holds a significant portion of the baryonic matter angular momentum and harbors at least two primary stellar populations: the thin and thick disks. Understanding the formation and evolution of the Galactic disk is crucial for comprehending the origins and development of our Galaxy. Stellar archaeology offers a means to probe the disk's evolution by listening to the cosmological narratives of its oldest and most pristine stars, specifically the metal-poor stars. In this study, we employed accurate photometric metallicity estimates and Gaia Early Data Release 3 astrometry to curate a pure sample of the oldest Galactic stars. This proceeding presents a summary of our primary findings.

Natálya Cristiana Pereira Pinheiro

Este artigo tem como objetivo aprofundar a análise das referências históricas compreendidas entre os séculos XVIII e XIX, explorando as espécies botânicas e práticas agroecológicas dos povos indígenas na região do Alto Rio Tapajós. Busca-se estabelecer um diálogo entre a etnohistória, etnobotânica e arqueologia, visando contribuir para a compreensão da construção de florestas culturais ao longo do rio Tapajós. Utilizando como base exemplos de povos do Tronco Tupi (Apiaká, Kaiabi, Munduruku e Sateré-Mawé), este estudo se propõe a examinar as complexas relações entre comunidades indígenas e a agrobiodiversidade, evidenciando a riqueza cultural e os sistemas de manejo antigo na região.

Randall Souza

Archaeologists deploy a variety of models and theories, often tailored to specific questions or situations, in making sense of the material record we study. The concept of the community of practice, originally developed in the context of modern work and learning situations, describes among other things how participation in shared activities can create and shape social relationships. It therefore offers a powerful and flexible framework for the many archaeological research agendas in which group dynamics play a role. Some archaeologists have already begun to use the community of practice approach (CoP) as an interpretive framework, and this essay argues that a wider embrace would be a benefit to individual archaeologists and to the field as a whole.

Saubin, Méline, Coville, Jérome, Xhaard, Constance et al.

Dispersal, and in particular the frequency of long-distance dispersal (LDD) events, has strong implications for population dynamics with possibly the acceleration of the colonisation front, and for evolution with possibly the conservation of genetic diversity along the colonised domain. However, accurately inferring LDD is challenging as it requires both large-scale data and a methodology that encompasses the redistribution of individuals in time and space. Here, we propose a mechanistic-statistical framework to estimate dispersal from one-dimensional invasions. The mechanistic model takes into account population growth and grasps the diversity in dispersal processes by using either diffusion, leading to a reaction-diffusion (R.D.) formalism, or kernels, leading to an integro-differential (I.D.) formalism. The latter considers different dispersal kernels (e.g. Gaussian, Exponential, and Exponential-power) differing in their frequency of LDD events. The statistical model relies on dedicated observation laws that describe two types of samples, clumped or not. As such, we take into account the variability in both habitat suitability and occupancy perception. We first check the identifiability of the parameters and the confidence in the selection of the dispersal process. We observed good identifiability for all parameters (correlation coefficient >0.9 between true and fitted values). The dispersal process that is the most confidently identified is Exponential-Power (i.e. fat-tailed) kernel. We then applied our framework to data describing an annual invasion of the poplar rust disease along the Durance River valley over nearly 200 km. This spatio-temporal survey consisted of 12 study sites examined at seven time points. We confidently estimated that the dispersal of poplar rust is best described by an Exponential-power kernel with a mean dispersal distance of 1.94 km and an exponent parameter of 0.24 characterising a fat-tailed kernel with frequent LDD events. By considering the whole range of possible dispersal processes our method forms a robust inference framework. It can be employed for a variety of organisms, provided they are monitored in time and space along a one-dimension invasion.

Tullio Basaglia, Zane W. Bell, Daniele DAgostino et al.

This paper summarizes Geant4 contribution to scientific research over the past 25 years through a scientometric analysis of the results with which it has been associated. The scientometric data collected from scholarly literature and databases are evaluated with methods pertaining to econometrics and ecology to quantify relevant traits, diversity and disparity in their scientific and geographic distributions, and to identify statistically significant trends. The analysis reviews the contribution of Geant4 to the field - experimental particle physics - that originally motivated its development and highlights its role in other research domains including nuclear physics and engineering, astrophysics and space science, biomedical physics, archaeology and the cultural heritage.

Anish Ghoshal, Yann Gouttenoire, Lucien Heurtier et al.

Light primordial black holes (PBHs) with masses smaller than $10^9$ g ($10^{-24} M_\odot$) evaporate before the onset of Big-Bang nucleosynthesis, rendering their detection rather challenging. If efficiently produced, they may have dominated the universe energy density. We study how such an early matter-dominated era can be probed successfully using gravitational waves (GW) emitted by local and global cosmic strings. While previous studies showed that a matter era generates a single-step suppression of the GW spectrum, we instead find a "double-step" suppression for local-string GW whose spectral shape provides information on the duration of the matter era. The presence of the two steps in the GW spectrum originates from GW being produced through two events separated in time: loop formation and loop decay, taking place either before or after the matter era. The second step - called the "knee" - is a novel feature which is universal to any early matter-dominated era and is not only specific to PBHs. Detecting GWs from cosmic strings with LISA, ET, or BBO would set constraints on PBHs with masses between $10^6$ and $10^9$ g for local strings with tension $Gμ= 10^{-11}$, and PBHs masses between $10^4$ and $10^9$ g for global strings with symmetry-breaking scale $η= 10^{15}~\mathrm{GeV}$. Effects from the spin of PBHs are discussed.

Fabian Hinterer, Simon Hubmer, Prashin Jethwa et al.

In this paper, we consider the problem of reconstructing a galaxy's stellar population-kinematic distribution function from optical integral field unit measurements. These quantities are connected via a high-dimensional integral equation. To solve this problem, we propose a projected Nesterov-Kaczmarz reconstruction (PNKR) method, which efficiently leverages the problem structure and incorporates physical prior information such as smoothness and non-negativity constraints. To test the performance of our reconstruction approach, we apply it to a dataset simulated from a known ground truth density, and validate it by comparing our recoveries to those obtained by the widely used pPXF software.

Valerii Otiakovskii

This is a review of a recent book on the formal method’s reception in the Soviet Ukraine. Published in the autumn of 2021, just several months before the beginning of Russia’s war against Ukraine, the book by Galina Babak and Alexander Dmitriev is of particular interest in the light of the inevitable upcoming reconfiguration of Slavic Studies. It both transforms and redefines the well-established ideas concerning the history of Russian (i.e., Moscow-Leningrad) formalism, outlining a previously unknown — and a very original — line of its perception. KEYWORDS: 20th-Century Ukrainian Literary Theory and Criticism, Galina Babak (b. 1988), Alexander Dmitriev (b. 1973), Book Review.

Die Redaktion

Sebastián Gómez Ruiz

This article is a case study of the exchanges and relationships that arose from the circulation of images in the Arhuaco community of Kutunzama in the Sierra Nevada de Santa Marta. The circulation of photographs, which show the present and past history of the Arhuaco people, led to an exchange between the mamos, the community and myself —as ethnographer—. The purpose of this text is to show how the circulation of these photographs can be understood as a gift in a process of redistribution based on the evocative, material and sensual capacities of the images. This article consists of an ethnographic approach, developed between 2017 and 2019, on the basis which the community’s forms of organization and kinship are understood via the elicitation of photographs and films, interviews and participant observation. This circulation also made it possible to activate narratives of the recent history of the village, related to the settlement and the context of territorial disputes in the area. Ethnographic photography allowed us to approach notions of time and space, and to broaden the Arhuaco notion of makruma. Rather than conceiving of this notion as a gift, it is understood as a process of redistribution in which the given object possesses the characteristics of the person who gives it and the return of the object (in this case the images) becomes a way of settling a spiritual debt. The text shows the image as a means of interaction, a means of encounter, a place of circulation and sensory experience. It approaches the image as a multisensory object and the photograph not only as a representational object, but also as one that traces social relations based on the indigenous notion of makruma.

Jennifer Bates

Domestication is one of the fundamental process that has shaped our world in the last 12,000 years. Changes in the morphology, genetics, and behavior of plants and animals have redefined our interactions with our environments and ourselves. However, while great strides have been made towards understanding the mechanics, timing, and localities of domestication, a fundamental question remains at the heart of archaeological and scientific modelling of this process—how does domestication fit into a framework of evolution and natural selection? At the core of this is the ontological problem of what is a species? In this paper, the complicated concepts and constructs underlying ‘species’ and how this can be applied to the process of domestication are explored. The case studies of soybean and proto-indica rice are used to illustrate that our choice of ‘species’ definitions carries with it ramifications for our interpretations, and that care needs to be made when handling this challenging classificatory system.

م. مالك مهدي حايف

ملخص البحث :  عدَ المؤرخون دراسة الجوانب التاريخية بعصورها المتعددة في التاريخ العربي الإسلامي من خلال كتب الأدب والبلاغة بالدراسات المهمة, لأنها تتطرق إلى أحداث تاريخية مغمورة في هذه الكتب, فهذه الدراسة تهدف إلى معرفة هذه الحوادث التاريخية ومن ثم مقارنتها بأمهات المصادر, لذا انصَبت دراستنا بموضوع البحث الذي تناول اسارى غزوة بدر الكبرى سنة 2ه ومقدار فدائهم في التاريخ الإسلامي من خلال كتاب (نهاية الإرب في فنون الأدب) لأبي العباس شهاب الدين النويري(733ه/1332م), والذي اشتمل على مبحثين, تناول المبحث الأول: الملامح العامة لسيرته ونشأته العلمية, متضمنة: اسمه ونسبه, ولقبه وكنيته, وولادته ونشأته, ووفاته, وشيوخه, ومنهجه وموارده, وعلاقته وتقربه من الأسرة الحاكمة التركية, فضلاً عن مؤلفاته, أما المبحث الثاني: فتناولت الدراسة: أسارى غزوة بدر ومقدار فدائهم من خلال كتابه, والتي تضمنت بيان معنى الإسار والفداء لغةً واصطلاحاً, وتسمية من أسر من المشركين في هذه الغزوة, وبذكر عدد من الأسرى الذين ذكرهم النويري في كتابه.  

Óscar Hernández-Muñoz, Alicia Sánchez-Ortiz

The three-dimensional models of wax belonging to the scientific heritage of the Complutense University of Madrid are a rare and extraordinary material that deserves to be preserved because it has great relevance to understand how surgeons and anatomists found formulas of visual construction that made possible the diffusion of his knowledge about the human body. In the present investigation, an anatomical wax model of the 18th century, with a remarkable degree of structural deterioration and weakness, has been restored, testing a new volumetric loss reconstruction methodology based on photogrammetric digitization of the sculpture, 3D modelling of the lost pieces and 3D printing of their moulds to obtain from them the final copies in waxy material. Due to this methodology, it has been possible to reduce the handling of the figure during the restoration process and the risk of accidental deterioration has been minimized.

Glauco Constantino Perez, Mercedes Okumura, Marisa Coutinho Afonso et al.

Este artigo apresenta um estudo de caso explorando o amplo potencial de aplicação do programa de estatística R na análise de dados arqueológicos. O programa R é um ambiente de desenvolvimento integrado para cálculos estatísticos e gráficos, tendo seu uso a partir de pacotes que são bibliotecas de cálculos aplicadas a áreas de estudo específicas. Neste artigo, utilizam-se dados dos sítios arqueológicos dos grupos ceramistas das tradições Tupiguarani e Itararé-Taquara, que se localizam nas bacias dos Rios Tietê e Paranapanema no Estado de São Paulo, como estudo de caso para a utilização do método. Apresentam-se análises descritivas de atributos elencados previamente e análises inferenciais com modelos de regressão logística de Distância Euclidiana (DE) e Regressão logística Bayesiana.