Known as lead white, lead carbonates were used as white pigment or cosmetics from the 4th century BC to the 20th century AD. Lead white was produced by the corrosion of metallic lead by vinegar and horse manure up to the 19th c. In order to document the incorporation of carbon in the corrosion mechanism, lead carbonates were produced in the laboratory under monitored experimental conditions using materials with different isotope signatures in 14C and 13C. Six experimental setups were defined combining vinegar, acetic acid, horse manure and fossil CO2 gas. The corrosion products were characterized by X-ray diffraction. 14C content and δ13C values of the initial reactants and the final products were measured by accelerator and isotopic ratio mass spectrometry (AMS and IRSM). The reaction between lead and vinegar or acetic acid resulted in lead acetates with a carbon isotopic signature close to that of the corrosive reagent. In the presence of CO2, the carbonatation reaction occurred and the cerussite produced had a predominant 14C signature of the carbon dioxide source. These experiments demonstrate that the CO2 produced by horse manure fermentation is incorporated into the corrosion products, allowing the absolute dating of lead white by the radiocarbon method.

Desde la antigüedad, los artefactos de pizarra fueron utilizados por sociedades asentadas en diversos puntos del continente americano; su uso abarcó diferentes temporalidades y múltiples formas.

En el caso particular de Teotihuacán, ubicado en el centro de México, los artefactos en cuestión se reportan dentro y fuera de esta ciudad, depositados como ofrenda y asociados directamente al fuego, al agua y al inframundo. Aunque la pizarra fue una materia prima con una presencia constante en Teotihuacán, sólo se reconoce cuando aparece asociada a los espejos, cuando presenta diseños iconográficos, o con evidencia de decoración. Al respecto, en este texto señalamos la importancia de la pizarra en Teotihuacán, su cronología y contexto. De acuerdo con los resultados de los análisis tipológicos, geológicos y de caracterización, proponemos el aprovechamiento de diversas materias primas dentro de un mismo yacimiento, así como la identificación de las áreas de extracción de la pizarra utilizada por los teotihuacanos a través del tiempo.

Estos datos nos permiten inferir las funciones rituales, simbólicas y jerárquicas de esta materia prima dentro de la metrópoli teotihuacana.

A comparison theorem for state-dependent regime-switching diffusion processes is established, which enables us to pathwise-control the evolution of the state-dependent switching component simply by Markov chains. Moreover, a sharp estimate on the stability of Markovian regime-switching processes under the perturbation of transition rate matrices is provided. Our approach is based on elaborate constructions of switching processes in the spirit of Skorokhod’s representation theorem varying according to the problem being dealt with. In particular, this method can cope with switching processes in an infinite state space and not necessarily of birth–death type. As an application, some known results on the ergodicity and stability of state-dependent regime-switching processes can be improved.

The Classic period lowland Maya used iron-ore mosaic mirrors and deposited mirrors in the burials of rulers and other people. Depictions of mirrors suggest that they were used for scrying, as were mirrors in Mesoamerica at the time of the Spanish arrival. Maya mirror users of this kind were conjurors, who used a variety of other divining and conjuring instruments and materials, including plates and shallow bowls. Three rulers at El Peru-Waka', now called Waka' by researchers at the site, an ancient city in northwestern Peten, Guatemala, were buried with mirrors and associated divining and conjuring materials. Following a brief introduction to the city and its temples, we describe the arrangement of mirrors and associated materials in three royal tombs. We suggest that the mirrors in these tombs were used in conjuring supernatural beings into existence, particularly Akan, a death god and wahy spirit who was a patron of the Waka' realm. We propose that the rulers and mirror conjurors of Waka' were oracles and that Waka' was known for prophecy. References to Sihyaj K'ahk' in text and iconography at Waka', and his association with oracular paraphernalia such as mirrors, lead us to propose a prophetic aspect of the visit of Sihyaj K'ahk' to the site eight days prior to his famous arrival at Tikal in a.d. 378. We suggest that the three rulers we discuss were mirror oracles sustained by the prestige of the prophecy of Sihyaj K'ahk'.

The story of the Somnath temple, in the northwestern Saurashtra peninsula, has often been taken as an example of the contentious legacies of the penetration, settlement, and political establishment of Muslims in India. Its history testifies to the complex relationship between history, heritage, and the consolidation of collective memories of past events and processes.

This article focuses on two key moments in the temple's recent history: the retrieval of the Somnath gates by Lord Ellenborough in 1842 and the reconstruction of the temple between 1947 and 1951. At these two moments—one during colonial times and the other at the creation of the independent state—Somnath became the battlefield for questioning how the state should be positioned with regard to religious places, histories, symbols, and practices.

While the temple was apparently dealt with as a tangible place of heritage, both episodes show how the value endowed upon the temple had far more complex meanings. The analysis proposed in this article ends with the reconstruction of the temple. This shows the way in which architects of independent India addressed the country's history, directly or indirectly engaging with the construction of a heritage for the new state. Their efforts aimed to strengthen a shared memory of the past, which could in turn consolidate membership and a sense of belonging to the new nation. Advocates and promoters of the temple's reconstruction, among whom were Vallabhbhai Patel and K. M. Munshi, envisioned that the reconstruction would embody the long-awaited liberation of India from centuries of continuous domination by ‘foreign’ powers. In contrast, secular politicians, with Nehru at the helm, opposed the reconstruction, fearing that Somnath might become the symbol of a sectarian vision of the nation and, in the wake of partition, derail efforts to characterise independent India as an inclusive country. While the reconstruction did eventually take place, the entire episode invites us to question the relationship between the framing of Indian nationalism and the heritagisation of Indian history. Following a critical theoretical approach to Heritage studies, where heritage has less to do with the item that is preserved than with the value with which it is endowed, this article proposes to investigate the meanings that heritage preservation, conservation, and reconstruction acquired as part of the project of nation- and state-building.

A simple model by which Hardy-Weinberg proportions are attained in a single generation while maintaining gene frequencies is stated and illustrated. The title ‘Quasi-random mating’ is proposed. Confusion about the Hardy-Weinberg principle can be avoided only if there is clear separation between the basic deterministic model and factors influencing a population’s structure. Eighty years passed before C. C. Li coined the term ‘pseudo-random mating’. The lesson taught by Li has not been taken on board.

In the aftermath of the United States’ 2020 presidential election, state legislatures have introduced and passed an unprecedented number of restrictive voting bills. While past research has looked at the state-level drivers of restrictive voting legislation, this project explores what factors predict which legislators within states push for these laws. Specifically, I ask whether district-level characteristics predict when lawmakers use bill sponsorship to send messages about their positions beyond those sent by simple roll-call votes. I use theories of geographical threat and racial resentment to predict where sponsorship of these bills is most likely. My results tie these theoretical expectations to observed legislative activity: the whitest state legislative districts in the least-white states were the most likely to be represented by lawmakers who sponsored restrictive bills, as were districts with the most racially resentful white residents. I conclude that, despite lawmakers justifying these restrictive laws by claiming that fraud is a major problem, race and racism are inherently tied to the introduction and passage of these bills. This raises important questions about commitments to multiracial democracy.

This Special Section focuses on recent research centered on iron-ore mirrors in Mesoamerica and Central America. Iron-ore mirrors are rare and esoteric artifacts, mainly crafted by specialized centers in the Maya, central Mexico, and Zapotec areas from the Early Preclassic to the Postclassic. They were found in numerous archaeological sites and cultures, from the Gila River in the United States to the isthmus of Panama.

In this introduction, we present a temporal, geographical, and contextual framework for the actual knowledge on mirrors, in order to fully understand the complexity and importance of the research on these prestigious artifacts. Indeed, the mirrors combine spiritual and political power in a portable and material way, giving a great insight into Mesoamerican beliefs and leading to important information on the relation between rulers of different political centers from different cultural areas.

Finally, we present the articles of the Special Section and give an overview of their content and relevance to the topic.

In this paper, we study the relationship of the Brouwer degree of a vector field with the dynamics of the induced flow. Analogous relations are studied for the index of a vector field. We obtain new forms of the Poincar é–Hopf theorem and of the Borsuk and Hirsch antipodal theorems. As an application, we calculate the Brouwer degree of the vector field of the Lorenz equations in isolating blocks of the Lorenz strange set.

Different types of iron ore and pyrite were used to craft a wide variety of reflective artifacts in pre-Columbian Mesoamerica, including “mirrors,” pectorals, necklaces, and dental inlays, among others. In the Maya region, most of these have only been visually assessed, without using analytical techniques. Consequently, our understanding of the diversity of raw materials used in artifact production has been limited. This article presents preliminary results from a pilot study aiming to identify the raw materials used in the manufacture of different reflective objects from a small sample of finds from the sites of La Corona and Cancuen, located in Guatemala, through the use of scanning electron microscopy with EDS detectors (SEM-EDS), energy-dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), and Raman spectroscopy. Although further analyses are needed to confirm the representativeness of the sample, these results indicate the use of hematite and goethite (iron oxides), but not pyrite (iron sulfide). This study also shows how improved knowledge of raw material use can elicit previously unknown patterns of distribution and exchange, and highlight patterns of inter- and intrasite variability in the production, use, and exchange of reflective objects over time in the Maya region throughout the Classic period.

El sitio de Tak'alik Ab'aj se encuentra en la bocacosta suroccidental de Guatemala. Durante las excavaciones del Entierro 1 de la Estructura 7A, fechado para finales del preclásico tardío (150 d.C.), se recuperó un rico ajuar funerario compuesto por decenas de piezas de jadeitita, hematita, pirita y cuatro mosaicos “reflectores” de este mismo material. Cada uno fue labrado con la misma tecnología de manufactura y soporte “flexible” de fragmentos de cerámica (ensamblados con resina) por primera vez documentado, y diseño propio para la función y significado que desempeñara. Dos de ellos fueron integrados en la pechera y faldellín del traje ceremonial; los otros dos como parte del ajuar adicional de un posible portaestandarte.

En este trabajo se incluye el estudio traceológico-tecnológico de las teselas de estos mosaicos del Entierro 1 a través de la caracterización de sus huellas de manufactura con arqueología experimental y microscopías óptica y electrónica de barrido. De esta manera se detectó una elaboración muy estandarizada en la que se aprovecharon instrumentos hechos con rocas volcánicas locales, como la dacita, cuyo sello tecnológico no ha sido reportado hasta el momento en otra colección lapidaria maya.

Smith and Kidder (1951:44) were among the first to highlight pyrite pre-Hispanic mirrors as “marvels of painstaking craftsmanship.” These mirrors present reflective surfaces consisting of 20–50 pyrite tesserae with beveled edges, perfectly cut, and average 2 mm in thickness. The first known examples of mirrors in Mesoamerica were the “Olmec” type—a concave mirror created from a single hematite piece developed during the Middle Preclassic period. Later, in the Classic period, pyrite mosaic mirrors replaced them. Unfortunately, we do not understand the changes from one type to the other. In this work, we present two pyrite mirrors found at the site of Chiapa de Corzo, Chiapas, Mexico, dating around 700–500 b.c., as possible forerunners of Classic pyrite mirrors. Also, we present traceological analysis of their manufacturing process using experimental archaeology and scanning electron microscopy. Based on these examinations, we identify likely materials and techniques employed in crafting them. We posit that production of these mirrors could have been the result of the development of specialized artisans at distinct workshops, increasing the complexity and labor investment in the lapidary objects as prestige goods.

Association of Pulmonary Artery Aneurysm with Ischemic Heart Disease is uncommon, and its surgical management has been rarely described in the literature. Surgical intervention should be individualised according to the coexisting diseases and comorbidities to achieve optimal outcome. We report a case of a 76-year-old man with background history of coronary artery stenting due to ischaemic heart disease. The patient presented with features of coronary compression due to giant pulmonary artery aneurysm. He was operated with replacement of aneurysmal pulmonary trunk with 25 mm Hancock conduit.

In this paper, a new design approach for the six-port (SP) junction is introduced. The proposed design includes a generalized broadband matching and smooth miniaturization scheme and is extendable for any passive multiport structure. A multilayer technology and a microstrip to slot coupling operation are employed for the designed SP, which comprises power divider and three hybrid couplers. The conducted measurements of the constructed SP junctions validates the design approach. Optimal performance of the SP network in terms of miniaturization, bandwidth, and response accuracy were obtained for the 5G low band.

Under Article 41 of the UN Charter, the Security Council has established 31 sanctions regimes since 1966. Sanctions measures encompass a broad range of enforcement actions not involving the use of armed force. The measures have ranged from comprehensive economic and trade sanctions to more targeted measures such as arms embargoes, travel bans, and financial or commodity restrictions. In recent years, there have been increasing numbers of complaints from humanitarian organizations that sanctions cause or exacerbate humanitarian crises. The UN Office for the Coordination of Humanitarian Affairs (OCHA) has estimated that at least 222 million people were experiencing acute food insecurity at the end of 2022, the largest global food crisis in modern history. At the same time, the countries that need the most assistance are often subject to international sanctions regimes. As of March 2023, UN sanctions applied in nine of the top ten operations of the International Committee of the Red Cross.

The article is concerned primarily with Maulana Azad's early political and theological writings with a view to understanding his positions on Islam and the non-Islamic religions. It opens with a brief description of his discussion of Mughal history and religious culture, and then notes his portrayal of Shaikh Ahmad Sirhindi (d. 1624) as an exemplary political figure, who raised his voice against Akbar's heresy. This portrayal has had a significant historiographical afterlife. Several modern scholars followed Azad's reading. The article asks whether Azad was truly the first to have such a view of the saint, and thereby influenced the modern writings on Mughal India. We will notice that Sirhindi was already portrayed as a political figure in the Mughal-era historical accounts devoted to him. Azad only chose to work within a certain memory of Sirhindi—but why did he choose to use an earlier tradition and not a purely religious interpretive framework of his own for analysing and presenting the saint's position? The article examines Azad's rationale for such a portrayal in light of his political concerns. It then discusses in some depth the theological discourses in his Tazkira and the early issues of Al-Hilāl.