Mayra Dafne Manrique-Ortega

The limestones were important materials for pre-Hispanic civilizations; they were used to construct significant buildings and structures that played a crucial role in their culture. However, environmental factors have contributed to their deterioration, leading to their loss. Therefore, it is essential to conduct multidisciplinary research to develop new conservation treatments compatible with these materials. This research evaluated the behavior of Ca(Zn(OH)₃)₂·2H₂O (CZ) y MgO nanoparticles applied on stones samples. Firstly, the nanoparticles were synthesized using the sol-gel method and subsequently characterized by X ray diffraction (XRD) and scanning electron microscope (SEM). Therefore, it was applicated by dropwise on stones samples. Their effects were evaluated using non-destructive techniques, specifically velocity of ultrasound propagation (Vp) and contact angle measurements. The results showed that both treatments had a consolidated effect on the stones, with a significant increase on Vp recorded after the application. Additionally, variations in the contact angle were observed in the stones treated with CZ and MgO. Specifically, Stones treated with MgO reported lower contact angles values. This increased hygroscopicity behavior to suggest an enhances their water absorption capacity.

General health status of a stranded Tursiops truncatus of the oceanic ecotype in southern Gulf of Mexico, Campeche coasts: a multidisciplinary analysis

Enterolobium cyclocarpum and Piscidia piscipula are two important tree Fabaceae species distributed from the Yucatan Peninsula, Mexico. Our aims were focused on the E. cyclocarpum and P. piscipula seeds for: (1) to examine the seed permeability and imbibition rate, (2) to evaluate the effect of seed pre-germinative treatments, and (3) to characterize the structures involved on the presence of physical dormancy (PY). We used fresh seeds to determine seed permeability and imbibition rate, seed viability by means of tetrazolium test, furthermore, we applied mechanical scarification and boiler shocks for 5 s, 10 s and 15 s treatments. Morphological characterization of the seed coat was by Scanning Electron Microscope (SEM). Seed viability in E. cyclocarpum and P. piscipula were 100% and 96%, respectively. Seed permeability and imbibition rate in E. cyclocarpum were low. The highest germination in E. cyclocarpum was in the mechanical scarification (92%), while in P. piscipula, this parameter was in the 10 s boiling water treatment (76.0%). The presence of PY was confirmed in both species because they showed low seed permeability, and imbibition rate; furthermore, exhibited macrosclereids cells. The present research seeks to promote the sustainable use of E. cyclocarpum and P. piscipula.

Jadeite was greatly appreciated by pre-Hispanic cultures in Mesoamerica. Despite its importance, knowledge of its mining sources was lost after the Spanish conquest. In the 1950s the only confirmed jadeite deposits in Mesoamerica were found in the Motagua River Fault (MRF), Guatemala. The aim of this study is to present a methodology that is appropriate for the study of archeological jadeite objects using non-destructive spectroscopic and micro-ion beam analysis techniques. This methodology has been applied to perform mineral, elemental, and luminescence characterization of five jadeite samples from the MRF, with white, lilac, and green colors. Fourier-transformed infrared spectroscopy and X-ray diffraction analysis confirmed the presence of jadeite, albite, and omphacite as the main mineral phases in the samples. Elemental maps using particle-induced X-ray emission (PIXE) with a nuclear microprobe and elemental concentration analysis from individual mineral grains using micro-PIXE coupled with micro-ionoluminescence (IL) allowed the detection of minor feldspar, titanite, and grossular mineral contents. Distinctive features from the mineral, elemental, and luminescence characterization have been found that allow the identification of these five jadeite samples.

One of the most important Mayan cities of the Classic period (A.D. 200–900) of Mesoamerica is Palenque, in Chiapas. The Mayan civilization attributed great importance to greenstone minerals, in particular jadeite. This study covers the analysis of greenstones found in royal tombs of several temples corresponding to the Classic period: the Temple of the Skull, Temple of the Cross and Temples XVIII and XVIII-A. The aim of this research is to determine the use of greenstone minerals and the raw materials’ sources as a first step in understanding the development of Palenque and its relationships to other sites in the Maya region. Here, we present a non-destructive in situ study of lithic objects carried out by means of a several spectroscopic techniques, such as Raman, Fourier transform infrared (FTIR), X-ray fluorescence (XRF) and color measurements, at the Palenque site museum. FTIR and Raman allowed for the identification of minerals including jadeite, omphacite, amazonite, albite, muscovite and green quartz. Moreover, XRF was effective for in situ analysis of the elemental composition of the artifacts. This information was essential for sourcing the raw materials, in particular, jadeite. It was possible to infer the exploitation of an unknown source of jadeite for the earlier burial (A.D. 250–450). During this period the exploitation of the Verapaz and Motagua jadeite deposits also began. These sources were the primary deposits used for the manufacture of the artifacts studied from the period of A.D. 600–850. Also, a greater diversity of minerals is observed during the zenith of Palenque during this period, corresponding to the reign of Pakal. Although, between burials, the color of the artifacts is diverse, the color measurements indicated similarity in color among artifacts within individual burials.

Colonial mural painting developed in Mexico in XVI century after the conquest of the pre-Hispanic cultures following the evangelization process little information exists about the chronology of the paintings and workshops, the painters, the pictorial techniques or the materiality of this art work.In this work, we present the non-invasive methodology of study of the pigments and other components of nine mural paintings in three colonial Augustinian ex-convents located in Epazoyucan, Actopan and Ixmiquilpan, in the state of Hidalgo, central Mexico. These places were selected not only because of the inherent value and iconographic characteristics of the paintings, which date to the XVI and XVII century, but also because they are in the same region and are well preserved and in good condition. Then it is possible to compare their materiality and get new information to answer to some of questions related to these paintings.X-ray Fluorescence (XRF) and Raman spectroscopy were conducted using portable equipment on scaffolds after a global examination under ultraviolet light. We were able to distinguish between different pigments used for different colors such as vermillion, orpiment, and a copper pigment, for the bright red, gold yellow, and green, respectively. These pigments are characteristic of the known Mexican Colonial color palette. Apart from this, we also found the presence of indigo in the blues, minium, and cochineal. A first comparison among the mural paintings of the three sites indicates different palettes and painting periods.