Valley Of Mexico Research Articles

A panoramic view of hospitalized young children in the metropolitan area of the valley of Mexico during COVID-19

ObjectivesThis work provides an overview of young children's (aged 0-9) infectious diseases epidemiology, by exploring the link between various comorbid conditions, COVID-19, and death rate. MethodsPublic data on hospitalized young children was obtained from national databases of the Mexican health care system from 2020-2022. Data included age, year of entry, gender, the time between admission to death (hospitalization time), date of death, comorbidities, and admissions to the intensive care unit. Children were separated into age groups and frequencies were calculated. Binary regression models were developed to determine the correlation of comorbidities and COVID-19 to death as calculated by odds ratios (OR). ResultsFrom 2020-2022, there were 11,815 hospitalizations among young children, of which 15.98% were due to COVID-19, 2.55% of hospitalizations resulted in fatalities from which 32.45% of deaths were COVID-19 related. The highest case-calculated fatality ratio of COVID-19 infected young children was estimated at 7.04% by early 2020, but dropped to 2.11% by the end of the second semester of 2022. The most frequent comorbidities associated with their hospitalization and death for the general population were intubation (OR: 17.967), pneumonia (OR: 2.263), diabetes (OR: 7.301), cardiovascular diseases (OR: 1.528) and COVID-19 (OR: 261). For the COVID-19-positive group, the most impactful comorbidities were intubation (OR: 20.232), pneumonia (OR: 3.057), and diabetes (OR: 12.824). ConclusionChildren's hospitalizations and deaths were common during the pandemic; wherein major comorbidities played an important role. Therefore, effective comorbidity management and vaccination programs are essential to reduce hospitalizations and deaths among young children.

Urban mobility and comorbidities on the incidence and death from COVID-19 in the MAVM

Purpose: To identify and quantify, on one hand, the effect of public transportation modes on the incidence rate of COVID-19 infections and, on the other hand, the comorbidities more related to the rate of COVID-19 deaths in the Metropolitan Area of the Valley of Mexico during the first wave of the coronavirus pandemic. Methodological design: Two multi-linear regression models were fitted, considering the COVID-19 incidence rate and COVID-19 death rate as dependent variables. Transport, demographic, and healthcare variables were also considered as explanatory. The number of arrivals to a municipality using any mode of transportation was considered to identify the effect of public transportation modes on the incidence rate of COVID-19 infections, and the prevalence of healthcare was considered to determine which comorbidities (included in the model) are more related to the rate of COVID-19 deaths. Results: The greater the number of trips made using small public transport vehicles, the more significantly the incidence rates increase. The number of trips done by walking negatively affects the incidence rate of COVID-19. The prevalence of diabetes and pneumonia is highly associated with increased COVID-19 deaths. Research imitations: This study was carried out considering a hypothetical scenario where the containment measures did not affect the number of trips made in the study area due to the difficulty of obtaining updated data. Findings: Men are more likely to be infected than women. Not only are the comorbidities related to mortality due to COVID-19, but they are also risk factors for contracting the disease.

Long‐term processes between Classic and Postclassic populations in the Mexico basin

AbstractThe study of nonmetric traits is useful for establishing biological differences or affinities between populations. This study considered 12 nonmetric cranial characters. The objective is to compare five series of two different cultural horizons: three populations of the Teotihuacán Classic period and two of the Mexica Postclassic period. For the selection of nonmetric traits, those not altered by intentional cephalic modification were considered. From the sample of materials, it was assessed whether the populations of the Classic period could have biological and cultural affinity between them, making a migratory interpretation which indicates differences in nonmetric characters between them. The mean measure of divergence (MMD) was considered as bio‐distance. The distance matrix was analyzed using the unweighted pair group method with arithmetic mean and nonmetric multidimensional scaling. Frequencies were studied using the principal component analysis. Mantel test and partial Mantel test were used to compare the distance matrix obtained with the MMD with sites geographical distance matrix, type of settlements matrix, and period of the site's matrix. In none of those cases were found a correlation at the level. Making more plausible that the results of the nonmetric traits MMD matrix agree with a migration process. All methods agree on separating Classical populations into one group and Postclassic populations into another. The archeological contexts, and the study of the material culture found, agree with the analysis of nonmetric characters.

The Potash Identification (PID) Plot: A Rapid Screening Crossplot for Discrimination of Commercial Potash

Potash minerals are the primary source of potassium (K), which is used for the manufacture of gunpowder, fertilizer, and as a sodium-seasoning substitute. Commercial potash minerals are all evaporites. Because potassium-40 (40K) is radioactive (decaying to argon-40 (40Ar) and releasing a gamma ray (GR) in the process), commercial potash mineralization is often discovered when GR (γ ray) logs in petroleum wells drilled through evaporite sequences “go off scale.” However, not all potash minerals may be commercial sources of potassium via underground mining techniques, and potassium is not the only radioactive element. For example, the mineralogy of the McNutt “potash” Member of the Salado Formation in southeast (SE) New Mexico is extremely complex, consisting of multiple thin (i.e., less than 10 ft thick) beds of six low-grade (radioactive) potash minerals, only two of which are commercial for underground mining. There are also four nonradioactive evaporite minerals, one of which may interfere with potash milling chemistry and numerous claystones and marker beds (shales and/or volcanics), with GR count rates comparable to the low-grade potash mineralization in this sequence. Because of this complexity, traditional borehole wireline (WL) and logging-while-drilling (LWD) potash assay techniques, such as GR log-to-core assay transforms, may not be sufficient to identify potentially commercial potash mineralization for underground mining (Teufel, 2008) in SE New Mexico. Crain and Anderson (1966) and Hill (2019) developed linear programming and multimineral analyses, respectively, to estimate potash mineralogy and grades from multiple borehole geophysical measurements. However, both of these approaches require large sets of multiple log measurements. In SE New Mexico, petroleum wells are drilled through the Salado Formation evaporite (including the McNutt “potash” Member) with air, then cased and cemented in place without running WL measurements. Then, the wells are drilled out to total depth (TD) in the underlying sediments with water-based mud. Complete log suites are run from TD to the casing shoe, with only the GR and neutron logs recorded through the cased evaporite sequence for stratigraphic and structural correlation. As a result, essentially all recent oil and gas wells in SE New Mexico have casedhole gamma ray and neutron logs through the Salado evaporite. Hill and Crain (2020) developed a simple crossplot involving only GR and neutron log data, which could discriminate between anhydrous and hydrated potassium evaporite minerals. Logs from these wells could provide a rapid potash screening database if used properly. This technique can be used with both openhole and casedhole petroleum well logs, as well as corehole WL logs, and provides discrimination of commercial potash mineralization from noncommercial (potash and non-potash) radioactive mineralization. Case histories of the use of PID crossplots in evaporite basins of Michigan, Nova Scotia, Saskatchewan, and SE New Mexico are described. This technique may also be useful in screening potential potash deposits elsewhere in the world.

High-Performance Computing with the Weather Research and Forecasting System Model: A Case Study under Stable Conditions over Mexico Basin

High-Performance Computing with the Weather Research and Forecasting System Model: A Case Study under Stable Conditions over Mexico Basin

Three-dimensional numerical modeling of ground motion in the Valley of Mexico: A case study from the Mw3.2 earthquake of July 17, 2019

In this study, a 3D physics-based numerical approach, based on the spectral element numerical code SPEED, is used to simulate seismic wave propagation due to a local earthquake in the Mexico City area. The availability of detailed geological, geophysical, geotechnical, and seismological data allowed for the creation of a large-scale (60 km × 60 km in plan, 10 km in depth) heterogeneous 3D numerical model of the Mexico City area, dimensioned to accurately propagate frequencies up to about 1.3 Hz. The results of numerical simulations are validated against the ground motion recordings of the July 17, 2019, Mw3.2 earthquake, with peak ground acceleration exceeding 0.3 g about 1 km away from the epicenter. A good agreement with records is found, quantitatively evaluated through goodness-of-fit checks. Furthermore, for the lake zone, the simulated decay trend of the peak ground velocity with epicentral distance is reasonably close to the observations, for both horizontal and vertical components. In spite of some limitations, the simulations are successful to provide a realistic picture of seismic wave propagation both in the hill and in the lake zones of Mexico City, including the onset of long-duration quasi-monochromatic ground motion in the basin, with strong amplification at low frequencies (between 0.4 and 0.7 Hz). The numerical results also suggest that surface waves, with predominant prograde particle motion at the ground surface and large ellipticities, dominate the wavefield in the lake zone. Based on these positive outcomes, we conclude that this numerical model may be useful for both a better insight into the seismic response of the Valley of Mexico and the simulation of ground motions during larger-magnitude earthquakes, to generate improved seismic damage scenarios in Mexico City.

Carbon isotope chemostratigraphy, geochemistry, and biostratigraphy of the Paleocene–Eocene Thermal Maximum, deepwater Wilcox Group, Gulf of Mexico (USA)

Abstract. The Paleocene–Eocene Thermal Maximum (PETM) represents the most pronounced hyperthermal of the Cenozoic era and is hypothesized to have resulted in an intensification of the paleohydrologic cycle, including enhanced seasonality and increased sediment discharge to the coastal ocean. Although the PETM has been widely documented, there are few records from deposits that form the distal, deepwater components of large sediment-routing systems. This study presents new constraints on the stratigraphic placement of the PETM in the deepwater Gulf of Mexico basin through analysis of geochemical, carbon isotopic, and biostratigraphic data within a ∼124 m cored interval of the Wilcox Group. Biostratigraphic and carbon isotopic data indicate that the PETM extends over ∼13 m based on acmes in the dinoflagellate Apectodinium homomorphum and calcareous nannoplankton Rhomboaster cuspis as well as a ∼-2 ‰ shift in bulk organic δ13C values. A decrease in bioturbation and benthic foraminifera suggests that a reduction in oxygen of Gulf of Mexico bottom waters and/or an increase in sedimentation rates were coincident with the onset of the PETM. A ∼2 m lag in the depositional record separates the onset of the PETM negative carbon isotope excursion (CIE) and deposition of a 5.7 m thick interval of organic-lean claystone and marlstone that reflects a shut-off of the supply of sand, silt, and terrestrial palynomorphs to the basin. We interpret deposits of the PETM in the deepwater Gulf of Mexico to reflect the combined effects of increased erosional denudation and rising sea level that resulted in sequestration of sand and silt near the coastline but that allowed delivery of terrigenous mud to the deep sea. The similarity of oceanographic changes observed in the Gulf of Mexico and Atlantic Ocean during the PETM supports the inference that these water masses were connected during latest Paleocene–earliest Eocene times. Although deposition of typical Wilcox Group facies resumed during and after the PETM recovery, an increased influx of terrestrial detritus (i.e., pollen, spores, terrestrial organic debris) relative to marine dinoflagellates is suggestive of long-lasting effects of the PETM. This study illustrates the profound and prolonged effects of climatic warming on even the most distal reaches of large (≥1×106 km2) sediment-routing systems.

Regional modeling of groundwater recharge in the Basin of Mexico: new insights from satellite observations and global data sources

Regional groundwater recharge (GWR) is crucial to improving water management strategies; however, the lack of available data constrains its computation. Here, a practical approach using remote sensing data and global hydrological products was implemented to estimate regional GWR in the Basin of Mexico, a ~9,000-km2 basin in central Mexico with a population of ~25 million people, where groundwater represents the most important water source. The soil–water-balance (SWB) model was applied to estimate the regional GWR from 2000 to 2021 in the Basin of Mexico using four model setups, including climatological records from ground stations (M1), remotely based precipitation from CHIRPS (M2), bias-corrected precipitation from CHIRPS (M3), and CHIRPS with temperature from the Daymet product (M4), and other global soil and land use datasets. Furthermore, the regional GWR model was calibrated using runoff from streamflow gauges and evapotranspiration from empirical equations and remote sensing data. The mean regional GWR values estimated in the Basin of Mexico using the M1, M2, M3, and M4 setups were 37, 45, 38, and 45 mm/year (10.38, 12.57, 10.73, 12.61 m3/s), respectively. All setups agreed that the Sierra de las Cruces represents the dominant GWR area; still, larger differences were obtained at high elevations due to the lack of climatological stations. Results suggest that annual precipitation and GWR follow a potential relationship dominated by elevation and surficial lithology. Finally, remote sensing and global sources could be successfully used to depict regional changes in recharge patterns within data-limited basins.

Development of complex patterns of anthropogenic uplift and subsidence in the Delaware Basin of West Texas and southeast New Mexico, USA

The Delaware Basin in west Texas and southeast New Mexico is now the largest global oil producing basin, averaging ∼400,000 m3 (∼2,500,000 barrels) per day in 2022. The shale-dominated strata targeted for production can co-produce 4–5 times more water than oil, necessitating disposal by injection of ∼1,400,000 m3 (∼8,700,000 barrels) of water per day in 2022. Through a comprehensive assimilation of regional Sentinel-1 satellite radar data and analysis of production and injection, we show how petroleum operations have caused the development of complex and accelerating patterns of surface deformation from 2015 through 2021. We observe uplift from reservoir swelling, subsidence from reservoir contraction, and the development of linear features that are indicative of faulting. Subsidence is predominantly caused by production, and an important finding of this study is that the magnitude of subsidence is linearly proportional to total production. Uplift is caused by pressurization from wastewater injection of shallow permeable strata. The patterns of uplift are complex and extend laterally well-beyond areas where injection was performed. Linear surface deformation features are observed throughout the Delaware Basin, and they are lengthening and densifying as uplift and subsidence accelerate. Many of the lineations can be linked to known strata-bounded faults and shallow seismicity in the southern Delaware Basin where they serve as permeable and anisotropic conduits for pore pressure migration. In the Northern Delaware Basin, co-seismic rupture is hosted along basement-rooted faults that may link to the linear surface features. Understanding these dynamic changes in Delaware Basin is a pressing concern for management of subsurface reservoirs and safeguarding the surface environment. Concerns include ongoing induced seismicity, hazard of drilling through over-pressured strata, maintenance of integrity for newer wellbores, mitigation of flows of brine and petroleum fluids at the surface of old wellbores, and management of the pore space resource for wastewater injection.

COMPARING BIOAPATITE AND COLLAGEN RADIOCARBON DATES FROM A 16TH CENTURY CEMETERY CONTEXT—EL JAPÓN, XOCHIMILCO, MEXICO CITY

ABSTRACT El Japón is a 16th century hamlet site in the marshlands of the southern Basin of Mexico in central Mesoamerica. Radiocarbon (14C) dating and OxCal modeling of human bone collagen (n = 11) identifies a range of burials at El Japón cemetery from 1550–1650 cal. CE. The refined chronology identifies use of this rural settlement well after the onset of colonial government-sponsored relocation of Indigenous people to larger settlements (congregaciones). Historically documented information in this work supports chronological modeling beyond stand-alone calibration. Stable isotopic study of bone samples demonstrates similar sources of dietary protein and carbohydrates. The similarity of carbon sources for bone apatite (bioapatite) and collagen offers security that both bone fractions are viable 14C dating opportunities. Recent extension of this work examines bioapatite 14C dates (n = 5) from the same bone samples when quality parameters are met—atomic carbon-nitrogen ratios of 3.2–3.3 and collagen yield of 10–20%. No significant difference is found between collagen and bioapatite dates of the same individuals (p = 0.17, Mann-Whitney U test). 14C dates from human bone samples in this primarily terrestrial dietary context can be successfully acquired from either collagen or bioapatite fractions.

Salt Dissolution in the Permian Flowerpot and Blaine Formations Defines Limits of the Syracuse Basin in Western Kansas and Eastern Colorado

The Syracuse Basin is a large region of about 8,100 mi2 (21,000 km2) in western Kansas and eastern Colorado that is underlain by Permian-age salts in the Flowerpot and Blaine Formations of the Nippewalla Group. Originally thought to be a structural or depositional basin, detailed study around the perimeter of the basin shows that it is a dissolutional remnant wherein the salt beds are dissolved at all places around the basin’s margins. The two main salt units, the Flowerpot salt and the middle Blaine salt, consist mainly of displacive halite in red-brown shales and siltstones (mudstones). The Flowerpot salt is generally 200–300 ft (61–91 m) thick within the basin, but where most or all of the salt is dissolved outside of the basin, equivalent strata are 50–150 ft (15–46 m) thick. The younger middle Blaine salt is typically 45–60 ft (14–18 m) thick in the basin, and equivalent strata are 5–10 ft (1.5–3 m) thick where the salt is dissolved. Five areas selected for detailed study of the dissolution zone around the perimeter of the Syracuse Basin show that removal of about 250 ft (76 m) of Flowerpot salt occurs within horizontal distances ranging from about 930 ft (283 m) to as much as 14 mi (23 km). Structural cross sections show that sub-salt strata dip gently and uninterrupted beneath the dissolution zone, whereas strata above the salt are disrupted and are flexed down by an amount roughly equal to the amount of dissolved salt. This supports the thesis that the salt deposits are a dissolutional remnant and not a structural or depositional basin. In most areas, descending unsaturated groundwater dissolves the shallower middle Blaine salt first and then dissolves the deeper Flowerpot salt. But in two areas, unsaturated groundwater is sourced from a sub-salt aquifer, causing dissolution of the Flowerpot salt first and then the shallower middle Blaine salt. Salt dissolution occurred at different times in different parts of the Syracuse Basin. In most areas, it occurred mainly during the Pliocene–Pleistocene–Holocene Epochs, but locally it started before deposition of the Cretaceous or even from Late Permian through Early Cretaceous time. The original extent of the Flowerpot and middle Blaine salts went far beyond the current extent of the Syracuse Basin. Remnants of both salt units are present in six large regions that extend from the Denver Basin in northeast Colorado and western Nebraska on the north to the Anadarko and Palo Duro basins in Oklahoma, Texas, and New Mexico on the south, a total area of about 115,800 mi2 (300,000 km2). In all these regions, the two salt units have dissolutional limits like those at the perimeter of the Syracuse Basin. Dissolution of subsurface salt units can cause problems when or if underground cavities become so large that the roof of the cavity collapses and the cavity rises to the land surface to form a sinkhole or an area of ground subsidence. Problems can also arise when seismic-reflection surveys cross a dissolution boundary and false images of phantom structures are created in strata below the dissolution zone. Also, drilling through salt units must be done with care so that unsaturated drilling muds and formation waters do not cause cavity development in the salt. Dissolution of salt also can affect the quality of groundwater: Salt-dissolution brine can migrate into fresh groundwater aquifers and even render the water unusable for most purposes.

A comparing vision of the lakes of the basin of Mexico: from the first physicochemical evaluation of Alexander von Humboldt to the current condition

The Basin of Mexico is an endorheic lacustrine basin with an outstanding ecological and social history. There is evidence that it hosted human settlers since the late Pleistocene. This basin was home to great antique civilizations and many endemic species of flora and fauna. The main lake in the Basin was the Great Lake of Mexico, which was divided into five lakes and provided goods and services to the native communities. After the Spanish conquest, a rule was established to drain the lakes to prevent flooding in the city. The naturalist Alexander von Humboldt visited Mexico City in the early 1800s, and carried out the first formal scientific water quality analysis of the lakes of the basin. The Basin of Mexico gone through serious modifications due to urbanization and changes of land use reducing the lacustrine area to the virtual extinction of the lakes. The lakes are currently reduced to wetlands accounting for only 2.83% of the former lake and receiving mainly treated wastewater discharges. We carried out a comparative study between Humboldt’s results and the current characteristics of water from these lake remnants analyzed with the same methods that he used. In addition, we assessed several morphometric parameters and performed water quality assessments using modern methods. Changes in water quality characteristics and ionic composition were detected, with Xochimilco being the lake with the highest water quality score and Texcoco and Chalco showing major alterations. The drastic reduction in the area of the remaining water bodies and the modifications in their water quality are discussed.

SOIL SALINITY SHIFTS CULTIVABLE MICROBIAL COMMUNITIES OF WHEAT (Triticum turgidum subsp. durum) RHIZOSPHERE IN THE YAQUI VALLEY, MEXICO

Saline soils are a common issue in commercial fields using intensive and irrigated agricultural practices under arid or semi-arid climates, such as the Yaqui Valley in Mexico, one of the most important wheat-producing regions worldwide. This study aimed to assess the cultivable microbial diversity (having plant growth-promoting attributes) associated with wheat rhizosphere in commercial fields, under a saline soil gradient in the Yaqui Valley. Thus, seven wheat commercial zones were studied according to their electrical conductivity (0.9 to 6.4 dS cm-1). The isolation of microorganisms was carried out by dependent culture techniques, sequencing of the 16S (bacteria) and 5.8S (fungi) rRNA genes , and plant growth-promoting attributes were evaluated: phosphate solubilization (Pikovskaya medium), siderophore production (Chrome Azurol S medium), indole production (Salkowsky reagent), and hemolytic activity (Petri dishes 5 % Sheep Blood). Wheat commercial zones with 1.6 dS m-1 showed the highest fungal (2.59 x 106 CFU g-1 dry soil) and bacterial (2.88 x 107 CFU g-1 dry soil) populations, being Rhizopus and Bacillus the most abundant and well-distributed microbial genera, respectively. The impact of saline soils on the microbial metabolic background was not species- or genus-specific; it was at a strain-specific level. In addition, 52 % of fungal and 83 % of bacterial strains showed the ability to produce γ-hemolysis, suggesting it is not harmful to humans and animals. This work provides a microbial culture collection where their members have shown several beneficial traits that potentially increase the yield and quality of wheat growing under saline soil conditions.

Analysis of GHG Emission from Cargo Vehicles in Megacities: The Case of the Metropolitan Zone of the Valley of Mexico

Analysis of GHG Emission from Cargo Vehicles in Megacities: The Case of the Metropolitan Zone of the Valley of Mexico

Methodology for the Classification of Types of Land Use in the Metropolitan Area of the Valley of Mexico Based on the Spectral Signature of Satellite Images and its Effect on the Rainfall Simulation with the WRF Model

Methodology for the Classification of Types of Land Use in the Metropolitan Area of the Valley of Mexico Based on the Spectral Signature of Satellite Images and its Effect on the Rainfall Simulation with the WRF Model

Gender and sand extraction in the Usumacinta River basin

Globally, sand and gravel are the second most extracted natural resources by volume after water. Despite that, knowledge about social and gender implications of sand-supply systems is limited. Here we aimed to advance the understanding of practices and gender relations in sand mining at male and female spaces in the Usumacinta River basin in Mexico and Guatemala. Drawing from desk and field research carried out in 79 locations on the riverbanks of the Usumacinta River and eight tributaries, this paper examines the extractive activities, gender roles and conditions of the workers. Sand extraction is characterized by a large diversity of actors, forms of organization, and local practices. We provide empirical evidence of a prevalent gender imbalance in the sand mining sector, as well as between men and women's spaces. Women participate in sand-mining related works in 19.51% of the sites, although in half of those cases they perform administrative tasks from town offices. Overall, their roles are seen as peripheral and minor even as they sell and classify materials and contribute to organizational tasks. We argue that the low participation of women at extraction sites is due to a combination of physically demanding work conditions and deeply ingrained gender norms in rural communities.

Festulolium and annual ryegrass pastures associated with white clover for small-scale dairy systems in high valleys of Mexico

O Background: The implementation of polyphytic pastures composed of grasses and legumes is an important component of agricultural systems in temperate zones, since grazing pastures which can reduce feed costs— are a viable option for small-scale dairy systems (SSDS). Objective: To evaluate the continuous grazing of dairy cows in Festulolium pastures associated with annual and perennial ryegrass and with clover in two farmrs. Methodology: Two experiments were carried out. The first experiment was established in the municipality of Almoloya of Juárez using eight cows that were divided into two groups of four; the cows grazed on two pastures with Festulolium associated with annual ryegrass and they were fed with 3.6 kg DM/cow/day of commercial concentrate, for 16 weeks. The second experiment was carried out in the Northwest of State of Mexico; six multiparous cows grazed on two pastures, under a cross over design arrangement; one pasture features Festulolium cv Spring Green and the other, annual ryegrass. Milk and body condition ere measured every 3 and 12 d, respectively. Variables from both experiments were analyzed using a split-plot experimental design. Results: Neither experiment recorded significant differences for the net accumulation of forage, the height of the pastures, and their chemical composition (P>0.05). No significant differences between treatments (P>0.05) were recorded regarding the yields and chemical composition of the milk. Study Limitations/Implications: The study of mixed pastures can be an alternative for feeding grazing cows, helping to reduce costs in SSDS. Findings/Conclusions: Festulolium/annual ryegrass pastures with white clover are a viable forage alternative for small-scale dairy systems.

Seismic damage rates of buildings considering different repair policies

An approach is proposed for assessing the mean number of times the maximum interstory drift (ID) incurs undesirable seismic damage states annually. The formulation is generalized and can be transformed into a classical formulation to evaluate seismic damage rates while considering structural repairs after sustaining any degree of damage. The formulation adopts a repair policy, which is expressed in terms of an ID threshold, that correlates with a certain level of damage. If this threshold is exceeded by a single earthquake or by a cumulative damage process due to an earthquake sequence, the building is repaired or reconstructed. The damage rates of the structural response of reinforced concrete buildings located in the Valley of Mexico were analyzed in a case study. Three repair policies were considered. The damage rates were found to be associated to an adopted repair policy.

Composition and Flowering Quality of Cacahuacintle Maize Populations from the High Valleys of Mexico.

Cacahuacintle is one of the maize types with great demand for pozole preparation; however, little is known about the variation in chemical composition and flowered grain quality among populations. Physicochemical characteristics, flowered grain quality, pasting properties, and starch microstructure were evaluated in 33 populations of Cacahuacintle maize collected in Valles Altos, Mexico. The seeds samples of corn were obtained in 2017 from local farmers in the states of Mexico, Puebla, and Tlaxcala. Results were analyzed under a completely randomized design, and the ANOVA, Tukey test, and principal components were obtained. The ANOVA showed significance (p ≤ 0.05) in 18 of the 22 variables evaluated. The TE-6, AM-7, and CA-6 populations were outstanding for the good quality of their protein, pasting viscosity, and flowered grain quality. Nine populations collected in Calimaya, estate of Mexico, and Serdan Valley, state of Puebla, presented excellent physical, pasting, and flowery grain characteristics, with reduced protein content and lysine and tryptophan values typical of maize with normal endosperm. The softness of the endosperm grain, starch microstructural, and pasting characteristics of Cacahuacintle maize populations have a fundamental role in reducing the time and increasing the flowered grain volume, properties that were different from those observed in the Chalqueño, included as dent maize check. Variations in grain quality among Cacahuacintle maize populations is an important genetic resource for the improvement of the nutritional and flowering quality of Cacahuacintle maize.

Bacillus cabrialesii subsp. cabrialesii subsp. nov. and Bacillus cabrialesii subsp. tritici subsp. nov., plant growth-promoting bacteria and biological control agents isolated from wheat (Triticum turgidum subsp. durum) in the Yaqui Valley, Mexico.

Strain TSO2T, a plant growth-promoting rhizobacteria and biological control agent, was isolated from wheat rhizosphere sampled from the Yaqui Valley in Mexico. The strain was identified using a polyphasic approach. Based on its analysis of the full-length 16S rRNA gene, strain TSO2T was assigned to the genus Bacillus , which was supported by morphological and metabolic traits, such as Gram-positive staining, rod shape, spore formation, strictly aerobic metabolism, catalase-positive activity, starch, and casein hydrolysis, reduction of nitrate to nitrite, growth in presence of lysozyme and 2 % NaCl, citrate utilization, growth at pH 6.0, acid production from glucose and indole production from tryptophan. Additionally, strain TSO2T possesses swarming motility, presenting a featureless mat pattern that can cover the whole petri dish. The whole-genome phylogenetic relationship analysis elucidated that strain TSO2T is closely related to Bacillus cabrialesii TE3T. The maximum values for average nucleotide identity (ANI) and in silico DNA–DNA hybridization from the genome-to-genome distance calculator (GGDC) were 97 and 73.4 %, respectively, related to Bacillus cabrialesii TE3T, where both ANI and GGDC values were barely above the species delimitation threshold, but below the subspecies limit. Also, strain TSO2T showed the ability to produce a fatty acid (C18 : 0) that is not present in closely related Bacillus species. These results provide evidence that strain TSO2T is a novel subspecies of the species Bacillus cabrialesii , for which the name Bacillus cabrialesii subsp. tritici subsp. nov. is proposed. The type strain of Bacillus cabrialesii subsp. tritici subsp. nov. is TSO2T (CM-CNRG TB52T=LBPCV TSO2T). The description of this novel subspecies automatically creates the subspecies Bacillus cabrialesii subsp. cabrialesii subsp. nov. for which the type strain is TE3T (CM-CNRG TB54T=CCStamb A1T).