Valley Of Mexico Research Articles

Species Delimitation of Scavenger Flies in the Valley of Mexico.

Identification of species involved in cadaveric decomposition, such as scavenger Diptera, is a fundamental step for the use of entomological evidence in court. Identification based on morphology is widely used in forensic cases; however, taxonomic knowledge of scavenger fauna is poor for many groups and for many countries, particularly Neotropical ones. A number of studies have documented the utility of a DNA barcoding strategy to assist in the identification of poorly known and diverse groups, particularly in cases involving immature states or fragmented organisms. To provide baseline knowledge of the diversity of scavenger Diptera in the Valley of Mexico, we generated a DNA barcode collection comprised of sequences of the cytochrome c oxidase subunit 1 (COI) gene for all families sampled at a nature reserve located in this region. We collected and identified specimens on the basis of morphology and a species delimitation analysis. Our analyses of 339 individuals delineated 42 species distributed across nine families of Diptera. The richest families were Calliphoridae (9 species), Sarcophagidae (7 species), and Phoridae (6 species). We found many of the species previously recorded for the Valley of Mexico, plus 18 new records for the region. Our study highlights the utility of DNA barcoding as a first-step strategy to assess species richness of poorly studied scavenger fly taxa.

Prior oil and gas production can limit the occurrence of injection-induced seismicity: A case study in the Delaware Basin of western Texas and southeastern New Mexico, USA

AbstractWe demonstrate that pore pressure and stress changes resulting from several decades of oil and gas production significantly affect the likelihood of injection-related induced seismicity. We illustrate this process in the Delaware Basin (western Texas and southeastern New Mexico, USA), in which hydraulic fracturing and waste-water injection have been inducing numerous earthquakes in the southernmost part of the basin where there has been no prior oil and gas production from the formations in which the earthquakes are now occurring. In the seismically quiescent part of the basin, we show that pore-pressure and poroelastic-stress changes associated with prior oil and gas production make induced seismicity less likely. The findings of this study have important implications for the feasibility of large-scale carbon storage in depleted oil and gas reservoirs.

Triassic breakup of Pangea in southern Mexico: Thermochronological evidence from the Tianguistengo formation

Southern Mexico is a key area for unraveling the tectonic evolution of North America because it contains the stratigraphic and structural record of the major tectonic events that shaped this continental mass, such as the breakup of Pangea and the growth of the North America Cordilleran Orogeny. However, multiple reactivations of faults and erosion of the stratigraphic record do not permit to adequately assess the timing of these tectonic events. Although most authors suggested that lithospheric extension and exhumation of continental blocks during Pangea breakup started in Mexico by Early Jurassic time, works published in the last decade provide an increasing number of thermo-tectonic evidence of an earlier phase of continental thinning. In this work, we present detrital apatite thermochronological and geochemical data (trace elements including rare earth elements) from fluvial deposits of the Tianguistengo formation, which is the oldest stratigraphic unit of the Otlaltepec Basin, a major basin in southern Mexico that has been linked to Pangea breakup. Our data show that at least a part of the Tianguistengo formation was derived from the adjacent Pennsylvanian–Cisuralian Totoltepec pluton. Apatite fission-track-based time–temperature modelling for unreset apatite populations suggests that the main exhumation of the Totoltepec pluton, which prompted the deposition of a part of the Tianguistengo formation, took place during Late Triassic time. Thus, our results suggest that Pangea breakup in southern Mexico started at least by Middle–Late Triassic time (240–230 Ma), as it is recorded in the Otlaltepec Basin.

Scaling-up the installation of hybrid solar collectors to reduce CO2 emissions in a Mexican industrial sector from now to 2030

This work aims to study and analyze the technical and avoided CO2e emissions potential of scaling up a novel hybrid solar technology in the Food and Beverage (F&B) industrial sector in Mexico. The prospective analysis is developed establishing different economic and technological scenarios from 2020 to 2030, which are established based on energy demand historical data by location a local trends. A coupled Long-range Energy Alternatives Planning-TRNSYS (LEAP-TRNSYS) model is developed to determine the total hybrid solar collector capacity that need to be installed by 2030, and the CO2e abatement potential in the F&B industry. Valle de Mexico, Guadalajara, Monterrey, and Torreon were the identified regions with the greatest potential to deploy the proposed hybrid solar technology considering the F&B industry. The determined technical potential (total collector installation area) of the hybrid solar technology in the F&B sector was 7.25 million m2, 6.24 million m2, and 5.31 million m2 for the positive, stagnation, and negative economic growth scenarios, respectively. The deployment of the proposed hybrid solar technology has an excellent decarbonization potential in the studied sector, achieving by 2030 a CO2e emissions reduction of up to 51.7%, 43.51%, and 34.06% from the levels of 2018 for the negative, stagnation, and positive economic growth, respectively.

Settlement Patterns and Urbanization in the Yautepec Valley of Central Mexico

Abstract We carried out a full-coverage survey of the Yautepec Valley in the 1990s to reconstruct demography and settlements and their changes through time. We investigated the extent to which well-documented developments in the adjacent Basin of Mexico were paralleled in Yautepec, as well as the impact of regional empires and economies on local society. Our analyses focused on Teotihuacan relations in the Classic period and relations with the Aztec empire and the Mesoamerican world system in the Middle and Late Postclassic periods. In addition to locating, mapping, and describing sites and taking grab-bag artifact collections, we also made a series of systematic intensive surface collections (5 × 5 m) and test excavations at samples of Classic and Postclassic sites. In this paper, we describe the survey and changing settlement patterns in the Yautepec Valley. We also present several analyses of changing patterns of urbanization through the Prehispanic era. We conclude with a synthesis of changing social and cultural dynamics in this region.

Financialization of the pharmaceutical industry and its impact on urban peripheries in the Metropolitan area of the Valley of Mexico

The process of financialization is present in the health sector, particularly in the case of large pharmaceutical companies. In the case of Mexico, there has been an expansion of pharmacies with medical offices as a result of capital flows, but also due to the absence of a quality public health system. This paper analyzes how the contemporary processes of pharmaceutical company financialization have allowed the expansion of the medical office-based pharmacy scheme and, to a certain extent, the “substitution” of health services managed by public authorities in the urban peripheries of the Metropolitan Zone of the Valley of Mexico. Based on information from Farmacias Benavides and Farmacias Guadalajara, issued by the Mexican Stock Exchange, on several indicators on health and pharmacies in Mexico, as well as semi-structured interviews with residents of the metropolitan periphery, it is argued that the exponential growth of pharmacies in the last two decades is linked to the policy of expansion and construction of social housing. These housing projects, largely due to weak regulatory controls, do not develop an adequate health infrastructure both in qualitative and quantitative terms, thus favoring the opening of financial instruments that have allowed large pharmaceutical companies to expand in recent decades.

Decadal-scale spatiotemporal changes in land use/land cover of El Potosi Basin at semi-arid northeast Mexico and evolution of peat fire between 1980-2020 CE

We estimated decadal-scale changes to the land use/land cover in one of the many drought-prone agricultural basins (El Potosi Basin) of northeast Mexico by using the temporal satellite images of Landsat Multi spectral scanner (MSS), Thematic Mapper (TM) and Operational Land Imager (OLI) for 1980, 1990, 2000, 2010 and 2020 CE. Increase in land without shrub and permanent uncultivated (fallow) land, and reduction in coverages of the agricultural land and forest over the last four decades reflected the intensities of water scarcity caused from global warming as well as the agriculture related anthropogenic activities. Enhanced aridity led to 136-fold surge (ca. 2.5–340 km2) in abandonment of cultivated areas covering almost half of the basin. Absence of cropland in 2010 CE reflected the severe drought of early 21st Century but augmentation in usages of groundwater reestablished the agriculture a decade later in ca.15.7 km2. Over the last four decades, the subsurface fire from combustion of peat covered ca.17.4 km2 mostly at expenses of lands with and without shrub and agriculture land. Our temporal and spatial land use/land cover assessments might be helpful for private and government agencies to evaluate the short-term impacts of climate change and anthropogenic activities in order to mitigate their effects in this water scarce region.

Comparative study of the indoor apparent temperature of dwellings with different roofing in the Lower Papaloapan River Basin region

This research presents a comparative study and an indoor thermal comfort analysis of self-constructed dwellings with different roofing in the Lower Papaloapan River Basin in Mexico. These include concrete roofs, zinc-coated sheet metal, asbestos sheets and palm fronds, all with and without false ceilings. The comparative study takes into account the identification and analysis of different architectural typologies, materials, structural pathologies, as well as the construction processes and the number of hours in which a dwelling is inside the comfort zone proposed. Until now, there is no relevant information about the comfort zone for the inhabitants of the studied region. Thermal comfort analysis shows that the comfort zone for the region is difficult to achieve due to the temperature and humidity of the region. Among the roofing without a false ceiling, the dwelling with palm roofing had the best performance whilst housing with zinc roofing produced the worst. Moreover, palm roofing is an ecological and vernacular option that uses local materials. In the case of a false ceiling, a standardizing effect was observed for all types of roofing. New approaches to show and analyse data and some suggestions for improving comfort conditions within homes in the region were proposed.

SALT-MAKING IN MESOAMERICA: PRODUCTION SITES AND TOOL ASSEMBLAGES

AbstractCommon salt, or sodium chloride, has always been a strategic resource of primary importance throughout the world. In pre-Hispanic Mesoamerica, salt was used primarily for human consumption, as the native diet had little chloride or sodium, two chemical components that are indispensable for human health and nutrition. Here I discuss the traditional salt industries of Michoacán, Colima, Guerrero, the Basin of Mexico and Puebla, paying special attention to the production sites and the tool assemblages linked to salt production in these areas of Mesoamerica. This article sheds light on salt's role in the culture and history of the ancient Mesoamerican ecumene through the lens of ethnoarchaeology and ethnohistory.

Stability of basement-rooted faults in the Delaware Basin of Texas and New Mexico, USA

Since 2009 the Delaware Basin of Texas and New Mexico has experienced increased seismicity related to oilfield operations. Available, near present-day principal stress orientations, relative magnitudes, and vertical stress estimates are integrated to characterize 20 stress domains in the Delaware Basin. Data density, variability, and quality inform classification of most-likely, less likely, and least likely stress tensor fields. A new interpretation of Delaware Basin, 3D basement-rooted faults is analyzed for stability using most-likely stress tensors. Fault stability is expressed in terms of slip tendency (Ts) and critical pore pressure (ΔPfc). Individual faults are compared in terms of their stability and potential seismic capability, and stress scenarios can be compared for their effects on fault stability. Faults range from stable to critical under the conditions investigated, 8% of total mapped fault area may become critically stressed by small pore-pressure increases (1 MPa, 145 psi) above ambient. Comparison of stability measures with focal mechanisms of recent pore-pressure-induced seismicity indicates that Ts and ΔPfc have predictive value. This work provides critical information for earthquake hazard and mitigation studies in the Delaware Basin.

A Review of Climate Change Impacts on the USA-Mexico Transboundary Santa Cruz River Basin

In the parched Upper Santa Cruz River Basin (USCRB), a binational USA–Mexico basin, the water resources depend on rainfall-triggered infrequent flow events in ephemeral channels to recharge its storage-limited aquifers. In-situ data from the basin highlight a year-round warming trend since the 1980s and a concerning decline in average precipitation (streamflow) from 1955–2000 to 2001–2020 by 50% (87.6%) and 17% (63%) during the winter and summer, respectively. Binational sustainable management of the basins water resources requires a careful consideration of prospective climatic changes. In this article we review relevant studies with climate projections for the mid-21st century of four weather systems that affect the region’s precipitation. First, the North American Monsoon (NAM) weather system accounts for ~60% of the region’s annual rainfall. The total NAM precipitation is projected to decline while heavy rainfall events are expected to intensify. Second, the frequency of the pacific cold fronts, the region’s prevalent source of winter precipitation, is projected to decline. Third, the frequency and intensity of future atmospheric rivers, a weather system that brings winter rainfall to the region, are projected to increase. Fourth, the frequency and intensity of large eastern pacific tropical cyclones (TC) are expected to increase. On rare occasions, remnants of TC make their way to the USCRB to cause storms with considerable impact on the region’s water resources. In contrast to the high confidence projections for the warming trend to persist throughout the mid-21st century, the precipitation projections of these four weather systems affecting the region encompass large uncertainties and studies have often reported contradicting trends. An added source of uncertainty is that the USCRB is located at the periphery of the four rain-bearing weather systems and small mesoscale changes in these weather systems may have accentuated impacts on their edges. Despite the high uncertainty in the projections of future precipitation, the early 21st century drying trend and the projected mid-21st century decline in precipitation events serve as a pressing call for planning and actions to attain sustainable water resources management that reliably satisfies future demands.

Frequency of risk infections for congenital infection in pregnant women

BACKGROUND: TORCH and other infections can be vertically transmitted and provoke abortions or result in congenitally infected newborns. Most babies are born with subclinical infection but have a high risk of developing sequalae later. OBJECTIVE: To determine the frequency of seven endemic infections that represent risk for vertical transmission among pregnant women of a tertiary care hospital. MATERIALS AND METHODS: Prospective, cross-sectional study carried out in pregnant women attended at the INPer between 2010 and 2012. Infections were investigated by serological risk markers among pregnant women living in the Valley of Mexico and answered a questionnaire including risk factors. RESULTS: A total of 1079 pregnant women were studied, and the overall frequency of infection was 5.7%. Anti-Toxoplasma gondii low avidity IgG (2.0%) and parvovirus B19 IgM (2.0%) were the most common. No HBV S-Ag and one rubella case were detected. An association of markers studied with fetal malformations and transfusions (p < 0.015) was found. Toxoplasma infection was associated with the last two variables, as well as with the consumption of raw meat, previous positive TORCH and infection with HPV. Parvovirus B19 IgM was associated with stillbirths, and T. pallidum with HIV. Four cases had double infections. CONCLUSIONS: This study supports the success of vaccination control programs against rubella and active HBV, although infections or perinatal risk are still challenging for this group of women and their children´s health.

Y chromosome diversity in Aztlan descendants and its implications for the history of Central Mexico

SummaryNative Mexican populations are crucial for understanding the genetic ancestry of Aztec descendants and coexisting ethnolinguistic groups in the Valley of Mexico and elucidating the population dynamics of the prehistoric colonization of the Americas. Mesoamerican societies were multicultural in nature and also experienced significant admixture during Spanish colonization of the region. Despite these facts, Native Mexican Y chromosome diversity has been greatly understudied. To further elucidate their genetic history, we conducted a high-resolution Y chromosome analysis with Chichimecas, Nahuas, Otomies, Popolocas, Tepehuas, and Totonacas using 19 Y-short tandem repeat and 21 single nucleotide polymorphism loci. We detected enormous paternal genetic diversity in these groups, with haplogroups Q-MEH2, Q-M3, Q-Z768, Q-L663, Q-Z780, and Q-PV3 being identified. These data affirmed the southward colonization of the Americas via Beringia and connected Native Mexicans with indigenous populations from South-Central Siberia and Canada. They also suggested that multiple population dispersals gave rise to Y chromosome diversity in these populations.

Water scarcity reduces the efficiency of the manufacturing industry in the valley of Mexico Basin: DEA-based two-stage efficiency analysis

ABSTRACT This study analysed the impact of a series of socioeconomic variables on the efficiency of production processes used by different economic units belonging to the manufacturing industry in a hydrological basin with water scarcity problems. The main finding is that the economic units that used water from overexploited aquifers had lower efficiency scores than those that used water from non-exploited aquifers. Thus, the design of public policies for this sector, which is highly dependent on this natural resource, should take into account that actions to conserve water supply sources greatly affect the efficiency of the manufacturing industry.

Deepwater sedimentary bedforms in a mobile substrate terrain: Examples from the central Gulf of Mexico Basin

We have used high-resolution geophysical data to investigate depositional and erosional bedforms in two geomorphologic provinces of the deepwater central Gulf of Mexico Basin: (1) the Mad Dog and Atlantis areas in the Sigsbee Escarpment region and (2) the Holstein minibasin within the salt canopy in the slope. Multibeam bathymetry indicates that the seafloor relief in the study areas is highly irregular because it is influenced by the dynamic behavior of underlying salt bodies resulting in the development of diverse bathymetric features. Side-scan images reveal erosional furrows of different morphologies at the base of the Sigsbee Escarpment that are oriented subparallel to the escarpment. Wide and sinuous furrows overlie mass transport deposits (MTDs), whereas, in other areas along strike, narrow rectilinear furrows are found beneath MTDs. The furrow fields in the Sigsbee Escarpment are located within a large series of erosional features that are linked to the action of westward flowing bottom currents associated with topographic Rossby waves that manage to rework sediments at water depths up to 2000 m. The interaction between the bottom current flow and the seafloor is likely influenced by the MTD’s irregular top surface relief and lateral changes in the escarpment’s morphology resulting in the development of complex sinuous furrow morphologies. North of the escarpment, subbottom profiles indicate a series of buried sediment waves found in the southern rim of the Holstein minibasin. Sediment wave morphometry indicates wavelengths ranging from 116 to 339 m and wave heights between approximately 0.8 and 2.4 m. Sediment waves were likely formed by turbidity currents as they exited the minibasin. The vertical change in topographic relief from the minibasin to the salt high led to variations in flow thickness and flow velocity of turbidity currents passing over the minibasin’s open rim. Consequently, these changes in flow regime led to the formation of sediment waves.

Residential patterns of Mexica human sacrifices at Mexico-Tenochtitlan and Mexico-Tlatelolco: Evidence from phosphate oxygen isotopes

This is the first systematic study of residential patterns of Mexica human sacrifices, as determined from bone and enamel phosphate oxygen isotope data of individuals recovered at the Templo Mayor of Tenochtitlan (n = 36) and the Templo R of Tlatelolco (n = 24). We identify these individuals’ geographic residences and compare these patterns with phosphate oxygen isotope data from a contemporary non-sacrificial group (Ecatepec; n = 24) from the Basin of Mexico. The sacrifices’ residential patterns are evaluated to assess their group membership (i.e., as locals, long-term residents, or non-locals from other regions of Mesoamerica). The Tlatelolco subadult and adult sacrifices were either locals or long-term residents. The Templo Mayor subadult sacrifices offered at several ceremonies were non-locals and long-term residents, while the adult sacrifices were long-term residents (e.g., slaves living in Tenochtitlan >10 yrs.) or non-locals (e.g., war captives, slaves, spoils-of-war sacrificed soon after arriving to the Basin). Our results demonstrate the Templo Mayor priests had broad access to long-term residents and non-locals with origins from Mesoamerican regions subjugated by the Mexica. This study illustrates the Mexica obtained individuals for sacrifice with a diverse range of physical, social, and geographic characteristics for their ritual ceremonies.

Chemical Mapping to Evaluate Post-Depositional Diagenesis among the Earliest Ceramics in the Teotihuacan Valley, Mexico

Chemical and mineral sourcing techniques are commonly employed in archaeology to reconstruct patterns of ceramic exchange and raw material procurement practices for the past, but the effects of post-depositional diagenesis are still often ignored despite a number of key studies warning that the composition of ceramics from archaeological deposits often diverges greatly from their original composition at the time of production. This current study on diagenesis derives from a large chemical and petrographic analysis of some of the earliest ceramics (1500–100 cal Before Common Era [BCE]) in the Basin of Mexico at a time when the development of ceramic trade networks helped to spread early stylistic canons across Mesoamerica. One important site, Altica, consistently presents ceramics that are high in barium. We use laser ablation-inductively coupled plazma—mass spectrometry (LA-ICP-MS) to map the cross-sections of several samples from this site with the idea that post-depositional intake of mobile cations would appear as enriched at the surfaces of the pottery and around pores. Conversely, cations that leach out of the fabric would exhibit depleted concentrations in those same areas. We find that barium and a suite of other elements (e.g., copper, zinc, lead, tin, arsenic, calcium, strontium, and vanadium) have been chemically altered due to nearly 3000 years of burial in the soil. We explore the implications of those revelations for properly sourcing archaeological ceramics found at the Altica site and provide additional guidance for archaeologists and geochemists who employ ceramic compositional sourcing elsewhere.

Population genetics of wild and captive Trachemysvenusta (Gray, 1856) (Reptilia: Emydidae) in the Usumacinta river basin in Mexico.

The Mesoamerican slider Trachemysvenusta is endemic to Central America and Southern Mexico. Several human-mediated disturbances, including habitat degradation and illegal hunting for food, have impacted its populations along the Usumacinta river basin. The extent to which these disturbances have affected the genetic diversity and population structure of T. venusta inhabiting the basin remains unresolved. To this end, we analyzed eight microsatellite markers in five wild populations of T. venusta from the middle and lower reaches of the basin as well as one captive population. Our results show high levels of genetic diversity for all analyzed populations, low F ST values, high gene flow and no genetic structure, indicating an absence of genetic differentiation across sites and, thus, a single panmictic population for the basin. Evidence of a genetic bottleneck was observed in two of the wild populations (and the captive one), indicating some impact from disturbances, whether from poaching or habitat fragmentation, despite the seemingly high connectivity of most populations. Results are discussed in terms of the relative importance of genetic parameters for the conservation of T. venusta, particularly in light of the importance of demographic stochasticity in local conditions undergoing rapid changes.

New approach for local C-band weather radar precipitation calibration

Weather radar calibration is a topic of great current interest because it is useful for various hydrological applications. Several methods have been developed for adjusting the relation between reflectivity data Z and rainfall intensity R (Z/R) because droplet size distributions in different storm events are unknown and highly variable in time and space. The present study developed and tested a new space and time window-based procedure for optimal local calibration of weather radar using Z/R relations and applying it to convective and stratiform storms in the lower Grijalva river basin in Mexico. Improving rain estimates from the Sabancuy, Campeche radar is essential because it monitors this basin, which is prone to floods. The resulting estimates of the optimal power-law (Z = ARb) window-based procedure (OP) are compared with those of the default Marshall and Palmer (MP) relation using the observed rain gauge records. The appropriate window was selected using a criterion that considers factors affecting the free fall of raindrops. For most of the storms tested, metrics for the OP models showed better values than those calculated for the MP ones. The best MP performance is when using smooth calibration data, achieving similar metric results to that of the OP. The proposed observed calibration method could be useful to improve the default MP model estimates at any weather radar with similar characteristics to the ones analyzed in this work. The resulting Z/R relations could improve precipitation radar estimates for hydrologic model inputs.

Exhuming theNahualli:Shapeshifting, Idolatry, and Orthodoxy in Colonial Mexico

AbstractThis article examines the relationship between ritual specialists,nanahualtinornahualistas(pl.) andnahualliornahual(sing.), and healing practices, adding context to the social roles they fulfilled and the range of feats they performed. The cases examined here reveal that nanahualtin operated as intellectuals in their communities because of their ability to control animals, prognosticate, and heal or harm individuals at will. Some nanahualtin shapeshifted from humans to animals while others possessed animal companions. The elevated status of nanahualtin led commoners to seek their advice, which conflicted with the established orthodoxy of the Catholic Church. Because clergymen championed the sacraments as the best way to access the divine, non-orthodox rituals performed in mountains, rivers, and caves were derided as idolatrous devil worship.The 11 criminal and Mexican Inquisition cases examined here range from 1599 to 1801. Two seventeenth-century cases (1678 and 1685) and one eighteenth-century case (1701) contain Nahuatl phrases and testimonies from Chiapas and Tlaxcala, respectively. The cases from Chiapas demonstrate the use of Nahuatl as a vehicular language outside the central valley of Mexico. This article examines the gender of the animals into which ritual specialists transformed as an emergent category from trial records, which provides insight into Catholic officials’ understanding of the nahualli. Last, this study notes social divisions between rural and urban clergy regarding the power of nanahualtin and the efficacy of their magic.