Areas Of Mexico Research Articles

Weather Extremes Influence Human Migration Between Mexico and the United States

Undocumented immigrants from agricultural areas in Mexico are most vulnerable to drought and seasonal weather patterns.

Integrative taxonomy reveals two new species of Maritrema Nicoll, 1907 (Digenea: Microphallidae Ward, 1901), parasitizing birds in the Gulf of Mexico.

Members of the genus Maritrema Nicoll, 1907 include endoparasites of aquatic birds and mammals, distributed worldwide. Adult specimens were collected from the intestines of three bird species (the great black hawks, Buteogallus urubitinga Gmelin; laughing gull, Leucophaeus atricilla Linnaeus; and the willet, Tringa semipalmata Gmelin) in three localities along the Gulf of Mexico. Photogenophores were sequenced for the large subunit (LSU) from nuclear rDNA, and the new sequences were aligned with other microphalloid sequences available in GenBank. The maximum likelihood and Bayesian inference analyses revealed three independent lineages, one corresponding to a previously described species, Maritrema corai Hernández-Orts, Pinacho-Pinacho, García-Varela & Kostadinova, 2016, and two representing two undescribed species. These two new species are described in the current study. Maritrema itzamnai n. sp. can be morphologically differentiated from its four congeneric species occurring in coastal areas of Mexico by having smaller oral (20-29 × 20-38 μm) and ventral (20-39 × 19-33 μm) suckers. In addition, Maritrema itzamnai n. sp. possess annular vitellarium instead of a horseshoe-shaped vitellarium. Maritrema kukulkanni n. sp. can be distinguished from its congeneric species reported from Mexico by possessing a larger oesophagus (44-117μm) and by having a vitellarium distributed in both the hindbody and forebody. Maritrema corai is the third species recorded in this study parasitizing the great black hawk (Buteogallus urubitinga); this represents a new host and locality record, expanding its distribution range from the Mexican Pacific Ocean to the Gulf of Mexico.

Presence of Mercury in an Arid Zone of Mexico: A Perspective Based on Biomonitoring of Mammals from Three Trophic Guilds.

Mercury (Hg) has been extensively studied due to its impact on the environment and health, but its effects on wild mammal populations are still poorly known. Therefore, the use of biomonitors has gained importance. Our objective was to report and compare, for the first time, the amount of mercury in small mammals belonging to three trophic guilds and to provide an initial toxicology perspective in the Mezquital Valley, a critically polluted area of Central Mexico. We quantified total Hg from the hair and liver of a nectarivorous bat (Leptonycteris yerbabuenae), an insectivorous bat (Corynorhinus townsendii) and a granivorous mouse (Peromyscus melanophrys) using atomic absorption spectrometry during the dry and rainy seasons. We compared the mercury concentrations between seasons, species and matrices. In all species, the average mercury content was higher in hair than liver, and there was no correlation between matrices. There was no difference in mercury content among species. Hg concentrations in the livers of P. melanophrys and C. townsendii were lower during the dry season than the rainy season, suggesting a seasonal decline in mercury availability. All of the values detected were below the neurotoxicity threshold reported in small mammals (10 ppm); however, we propose constant monitoring of Hg in their environment and confirm the utility of these species as biomonitors.

Rocky Mountain Spotted Fever in Children along the US‒Mexico Border, 2017-2023.

Rocky mountain spotted fever (RMSF) causes significant illness and death in children. Although historically rare in California, USA, RMSF is endemic in areas of northern Mexico that border California. We describe 7 children with RMSF who were hospitalized at a tertiary pediatric referral center in California during 2017-2023. Five children had recent travel to Mexico with presumptive exposure, but 2 children did not report any travel outside of California. In all 7 patients, Rickettsia rickettsii DNA was detected by plasma microbial cell-free next-generation sequencing, which may be a useful diagnostic modality for RMSF, especially early in the course of illness, when standard diagnostic tests for RMSF are of limited sensitivity. A high index of suspicion and awareness of local epidemiologic trends remain most critical to recognizing the clinical syndrome of RMSF and initiating appropriate antimicrobial therapy in a timely fashion.

The Tula Industrial Area Field Experiment: Quantitative Measurements of Formaldehyde, Sulfur Dioxide, and Nitrogen Dioxide Emissions Using Mobile Differential Optical Absorption Spectroscopy Instruments

The Tula industrial area in Central Mexico comprises, among other industries, a refinery and a thermoelectric power plant. It is well known for its constant emissions of gases into the atmosphere and considered an important area where pollutants released into the atmosphere have an influence on local and regional air quality. During March and April 2017, a field campaign was conducted with the objective of quantifying formaldehyde (HCHO), sulfur dioxide (SO2), and nitrogen dioxide (NO2) emissions from this industrial area using mobile differential optical absorption spectroscopy (DOAS) instruments. Calculated average emissions of the Francisco Perez Rios Power Plant and the Miguel Hidalgo Refinery were 3.14 ± 2.13 tons per day of HCHO, 362.08 ± 300.14 tons per day of SO2, and 24.76 ± 12.82 tons per day of NO2. From the measurements conducted, the spatial distribution patterns of SO2, NO2, and HCHO were reconstructed, showing a dispersion pattern of SO2 and NO2 towards the southwest of the industrial complex, impacting agricultural and urban areas. Occasionally, and usually during the morning hours, SO2 and NO2 were dispersed towards the north or northeast of the industrial complex. In the case of HCHO, dispersion was observed towards the south and southeast of the industrial complex. The far-reaching implications of this study are that for the first time, formaldehyde emissions were quantified. In addition, a follow-up study was conducted regarding nitrogen dioxide and sulfur dioxide emissions from the Tula Industrial area.

Spatial analysis to identify unauthorized municipal solid waste disposal sites in rural areas of southern Mexico.

The management of solid waste in rural areas of developing countries faces significant challenges due to economic constraints and irregular human settlements. These factors often lead to the creation of unauthorized disposal sites, which pose risks to human health, ecosystems and the economy. Remote sensing and geographic information system techniques provide a means to understand the complex issues associated with inadequate municipal solid waste (MSW) disposal. This study aimed to identify unauthorized disposal sites in the rural areas of southern Quintana Roo, Mexico, by examining land surface temperature (LST) and vegetation indices as potential indicators of unauthorized final disposal sites (FDSs). The findings reveal that 13% of the study areas have a high, moderate or low probability of hosting unauthorized disposal sites. Additionally, 3 authorized final disposal sites (FDSs) were confirmed, and 20 unauthorized sites were identified. LST and the normalized difference vegetation index were effective in detecting unauthorized sites, as these areas exhibited higher temperatures and less vigorous vegetation compared to adjacent areas. The results provide valuable insights into the issues associated with inadequate waste disposal in rural areas and offer information that can help optimize MSW management and mitigate its environmental and health impacts.

Commercial milk formula marketing entry points: setting the course of infant and young child feeding trajectories

BackgroundThere is a limited understanding of the dynamic influences that shape infant and young child feeding (IYCF) decisions over time. We conducted an innovative qualitative study to reconstruct IYCF trajectories across early life course phases, in the context of the socioecological model (SEM) and the commercial determinants of IYCF.MethodsWomen of different socioeconomic status were interviewed in two large metropolitan areas in Mexico. Our specific goal was to allow us to better understand if and how the commercial milk formula (CMF) marketing influenced breastfeeding decisions in a complex dynamic way involving the individual, relational, community and societal levels.ResultsHospitals, health professionals, and interactions with social media were key category entry points throughout the prenatal, perinatal, early infancy period and beyond. The CMF industry interfered by engaging a wide array of actors across the different layers of the SEM, most prominently the health care system and the workplace. Through its marketing strategies the CMF operates subconsciously and its messages are most effective when health institutions, health care providers, workplace spaces and social norms are weak in their support for breastfeeding.ConclusionsThe cases in our study highlight how, together with a weak breastfeeding counseling system, and health professionals who lack training in breastfeeding and normal infant behavior, lead to the opportunity for CMF marketing to shape infant feeding, and ultimately to the decision to feed formulas that some mothers were not planning to use and cannot afford.

Comparative Genomic Analyses of Colletotrichum lindemuthianum Pathotypes with Different Virulence Levels and Lifestyles.

Colletotrichum lindemuthianum is the most frequent pathogenic fungus of the common bean Phaseolus vulgaris. This filamentous fungus employs a hemibiotrophic nutrition/infection strategy, which is characteristic of many Colletotrichum species. Due to host-pathogen coevolution, C. lindemuthianum includes pathotypes with a diversity of virulence against differential common bean varieties. In this study, we performed comparative genomic analyses on three pathotypes with different virulence levels and a non-pathogenic pathotype, isolated from different geographical areas in Mexico. Our results revealed large genomes with high transposable element contents that have undergone expansions, generating intraspecific diversity. All the pathotypes exhibited a similar number of clusters of orthologous genes (COGs) and Gene Ontology (GO) terms. TFomes contain families that are typical in fungal genomes; however, they show different contents between pathotypes, mainly in transcription factors with the fungal-specific TF and Zn2Cys6 domains. Peptidase families mainly contain abundant serine peptidases, metallopeptidases, and cysteine peptidases. In the secretomes, the number of genes differed between the pathotypes, with a high percentage of candidate effectors. Both the virulence gene and CAZyme gene content for each pathotype was abundant and diverse, and the latter was enriched in hemicellulolytic enzymes. We provide new insights into the nature of intraspecific diversity among C. lindemuthianum pathotypes and the origin of their ability to rapidly adapt to genetic changes in its host and environmental conditions.

Identification of potential biological corridors for the bobcat (Lynx rufus) in a multipurpose area of northeastern Mexico

The objectives of the research were i) to determine patches and points of origin forthe establishment and connectivity of biological corridors, ii) to estimate the costarea for the establishment of biological corridors, iii) to define biological corridorswith viability for the dispersal of the bobcat (Lynx rufus) in a multipurpose area inReynosa, Tamaulipas. To monitor behavioral patterns, capture and recapturerecords were generated using the photographic sampling method. To calculatedensity, the results were entered into the statistical program CAPTURE. To modelthe potential habitat, the maximum entropy method (MaxEnt) was used. The costsurfaces were obtained with the maps in MaxEnt. The results showed that: i) thereare six patches and points of origin for the establishment and connectivity ofbiological corridors, which presented a mature community of Tamaulipanthornscrub, ii) most of the study area presents values ranging from medium to highon the cost scale, which is correlated with intense landscape modification, and iii)11 potential biological corridors were defined for the dispersal of the bobcat (Lynxrufus) in a multipurpose area in Reynosa, Tamaulipas.

Mangrove dynamics driven by Late Holocene drought at Laguna Bacalar, Mexico

Laguna Bacalar, one of Mexico's most significant near-coast lakes, remains underexplored in the context of its Late Holocene paleoecology. A 2,40 m long core was retrieved in northern Laguna Bacalar. Palynological and geochemical proxies were isolated and analyzed. Our findings reveal the intricate paleoecological dynamics and hydrodynamic shifts of this vital area in southeastern Mexico. Climate and ecological changes delineate three pivotal phases during the Late Holocene at Laguna Bacalar: (i) a period between 3600 and 3250 cal BP mirroring current climatic conditions with seasonal dry tropical forest and mangroves as the dominant vegetation and evidence of human activities indicated by the presence of fossil maize pollen, (ii) a relatively arid phase from 3250 to 2600 cal BP, influenced by heightened ENSO-driven precipitation variability and sea level rise favoring an estuarine environment at Laguna Bacalar, and (iii) a period between 2600 and 2200 cal BP, exhibiting hydrological conditions akin to contemporary conditions with wetland forest mangrove vegetation. These data ultimately underscore the region's susceptibility to regional climatic fluctuations and ecological resilience, providing a case study from which to predict future conditions and establish modern conservation policy for Laguna Bacalar and similar environments.

Silver recovery into lead bullion from a lead concentrate by direct reduction with Na2CO3 and SiC reagents

ABSTRACT Silver has been recovered in lead bullion from a lead concentrate throughout a direct reduction process. The lead concentrate was obtained from a plant that processes polymetallic minerals located in the central mining area of Mexico. The direct reduction process has been tested through mixtures of Na2CO3 and SiC that were put in contact with the lead concentrate at 1000 °C for 60 min to produce lead bullion containing silver and slag. The produced lead bullion containing silver and the slag after direct reduction trials showed that it is possible to recover about 90% of lead and 86.5% of silver into the lead bullion, leading to a low silver content in the slag phase (<0.2 wt.%). The slag was constituted mainly by sodium silicate compounds such as Na2SiO3, Na4SiO4, and Na2Si2O5, when 50 wt. % of Na2CO3 and 10 wt. % of SiC regarding the initial charge of the lead concentrate was used. The proposed process has been assisted thermodynamically by the software FactSage 7.6, which allowed us to predict the main expected compounds and understand the process mechanism for silver recovery into a lead bullion using Na2CO3 and SiC reagents.

Extreme temperatures and mortality risk in urban and rural areas of Mexico: are associations sensitive to epidemiologic study design?

Extreme temperatures and mortality risk in urban and rural areas of Mexico: are associations sensitive to epidemiologic study design?

Chía and its wild relatives: A superfood Salvia (Lamiaceae)

Societal Impact StatementAlternative crops are a promising approach to address the global food shortage that is exacerbated by climate change and wealth disparities. Some of these alternative crops are traditional food plants that have been widely traded for centuries, whereas others have only recently become more popular. Chía is a traditional native “superfood” that is the fruit of three distinct mint species. Chía (Salvia hispanica) is commercially cultivated and shares nutritional properties with California thistle sage (Salvia carduacea) and desert chía (Salvia columbariae). These wild relatives of S. hispanica are adapted to arid conditions and have potentially valuable genetic variation for the development of chía agricultural varieties. The development of nutritious, drought‐tolerant crops such as chía will increase the resilience of people to the impact of climate upheaval.SummaryIn the Spanish language, the word chía refers to the nutlet fruits of several Salvia species native to Mesoamerica. The process of domestication of S. hispanica altered several traits, including the absence of shattering fruits, which makes harvest easier and mechanizable. S. hispanica is commercially cultivated in Mexico, South America, Australia, and less so in Europe and Africa. Other edible chía species are not commercially cultivated, including S. carduacea, and S. columbariae. These Californian chías are traditionally harvested by hand since the fruiting calices shatter and release the nutlets. Here we compare these three edible chía species, review their uses by native peoples, describe their morphology, summarize their natural distributions and cultivation, and provide an identification key. Native peoples in North America have traditionally used chías for food, medicine, and oil. S. hispanica naturally occurs throughout areas of Mexico that receive summer monsoonal rains. As such, it is a summer annual with an erect habit and cauline, simple leaves. In contrast, the Californian chía species are distributed through areas of the Mojave and Sonoran deserts that receive winter rains. They are winter annuals and their rosettes of lobed, pubescent leaves are typical adaptations to arid conditions. Nutlets in these chía species are similar when dry, but cultivated S. hispanica nutlets produce extensive mucilage when wetted, while the other chía produce mucilage to a lesser extent. As consumer interest grows in superfoods like chía, crop breeders may use wild chía to breed varieties appropriate for areas affected by drought or in desert agroecological systems.

Factors that influence pedestrian walking speed and behavior at crosswalks: a study of three metropolitan areas in Mexico

ABSTRACT Walking is the most common mode of transportation in the world. The design standards may need to be adjusted to local conditions to ensure pedestrian safety in different parts of the world. The paper aim is to find the factors that influence the crossing speed of pedestrians and their behavior in the crosswalk, and thus provide better tools for the design of pedestrian facilities. Thirty crosswalks from four cities in Mexico were analyzed, obtaining a sample of 8700 pedestrian crossing speed records. The results show that land use, median design, pedestrian traffic signals, number of lanes, the day of the week, gender, age, carrying objects, pedestrian platoon size, population, and geographical area are significant factors in pedestrian crossing speed. In addition, it was observed that a significant number of pedestrians exhibit unsafe crossing behaviors. Male pedestrians were found to be more likely to exhibit these unsafe crossing behaviors.

Protected Natural Areas: A literary analysis of the Decrees of the Cerro de San Juan Biosphere State Reserve in Nayarit

Protected Natural Areas (ANP) in Mexico are key to conserving biodiversity but face challenges due to poor management and violations of environmental laws, resulting in degraded habitats. The LGEEPA and state laws are essential for their conservation, requiring alignment of local governments. Collaboration among governmental entities, research centers, and society is crucial to establish ANP that comply with environmental policies. A study in 2023 analyzed environmental legislation and its impact, aiming to identify effective regulations for local communities. For effective conservation, ANP need appropriate management categories, zoning, and plans supervised multidisciplinarily. This approach will ensure efficient management aligned with national goals for conserving and restoring ecosystems in Mexico.

Epidemiology of marine turtle fibropapillomatosis and tumour-associated chelonid alphaherpesvirus 5 (ChHV5; Scutavirus chelonidalpha5) in North-Western Mexico: a scoping review implementing the one health approach

Fibropapillomatosis (FP) - tumour-associated chelonid alphaherpesvirus 5 (ChHV5; Scutavirus chelonidalpha5) - is a disease that affect marine turtles around the world, and characterized by the formation of cutaneous tumours that can appear anywhere on the body. We carried out a thorough literature search (from 1990 to 2024) in the feeding sites of North-western Mexico, a region that hosts important habitats for feeding, development, and reproduction for five of the seven existing sea turtle species. We found 18 reports recording a total of 32 cases of FP and/or ChHV5/Scutavirus chelonidalpha5 in coastal and insular areas of North-western Mexico. Baja California Sur resulted with the highest number of cases (75%). While the first case of ChHV5/Scutavirus chelonidalpha5 infection was reported in 2004, the presence of FP tumours was reported in 2014 and became more frequent between 2019 and 2024. The affected species were black, Chelonia mydas (50%), olive ridley, Lepidochelys olivacea (46.8%) and loggerhead turtles, Caretta caretta (3.2%). Tumours occurred mainly in anterior flippers (46.1%) and neck (22.5%), and most had a nodular and verrucous appearance with a rough surface. In the study region, there is a potential sign of the emergence of the ChHV5/Scutavirus chelonidalpha5 infections and FP disease during the last 20 years, with a rapid increase during the last 10 years. As long as infections by ChHV5/Scutavirus chelonidalpha5 and the prevalence of the FP disease may be potentially influenced by anthropogenic activities, a One Health approach is needed to understand and improve sea turtles’ health.

Impact of the 2022 New Mexico, US wildfires on air quality and health

The 2022 wildfires in New Mexico, United States, were unparalleled compared to past wildfires in the state in both their scale and intensity, resulting in poor air quality and a catastrophic loss of habitat and livelihood. Among all wildfires in New Mexico in 2022, six wildfires were selected for our study based on the size of the burn area and their proximity to populated areas. These fires accounted for approximately 90 % of the total burn area in New Mexico in 2022. We used a regional chemical transport model and data-fusion technique to quantify the contribution of these six wildfires (April 6 to August 22) on particulate matter (PM2.5: diameter ≤ 2.5 μm) and ozone (O3) concentrations, as well as the associated health impacts from short-term exposure. We estimated that these six wildfires emitted 152 thousand tons of PM2.5 and 287 thousand tons of volatile organic compounds to the atmosphere. We estimated that the average daily wildfire smoke PM2.5 across New Mexico was 0.3 μg/m3, though 1 h maximum exceeded 120 μg/m3 near Santa Fe. Average wildfire smoke maximum daily average 8-h O3 (MDA8-O3) contribution was 0.2 ppb during the study period over New Mexico. However, over the state 1 h maximum smoke O3 exceeded 60 ppb in some locations near Santa Fe. Estimated all-cause excess mortality attributable to short term exposure to wildfire PM2.5 and MDA8-O3 from these six wildfires were 18 (95 % Confidence Interval (CI), 15–21) and 4 (95 % CI: 3–6) deaths. Additionally, we estimate that wildfire PM2.5 was responsible for 171 (95 %: 124–217) excess cases of asthma emergency department visits. Our findings underscore the impact of wildfires on air quality and human health risks, which are anticipated to intensify with global warming, even as local anthropogenic emissions decline.

Spatiotemporal Variabilities in Evapotranspiration of Alfalfa: A Case Study Using Remote Sensing METRIC and SSEBop Models and Eddy Covariance

Prolonged drought exacerbated by climate change in the Mesilla Valley, one of the major agricultural areas of New Mexico, USA, is causing a shortage of surface water from the Rio Grande for irrigation. Farmers in the Valley are using groundwater for irrigation and complementing it with limited surface water from the river (Rio Grande). Managing irrigation water better is vital to sustaining agriculture in the Valley. Remote sensing (RS)-based crop evapotranspiration (ETa) models offer significant advantages over traditional methods. The ET maps generated by these RS models provide valuable information that can be used to manage irrigation water and crops in water-scarce areas. This study used METRIC and SSEBop RS models to map the ET of alfalfa on a private farm that is managed as commonly practiced in the Valley. The integrated ET values of the two models are compared to those of the ETa measured using the eddy covariance method. The comparison showed that 91.55% of the variability in SSEBop ETa estimates can be explained by the variability in the METRIC ETa estimates, and the variability in eddy covariance ETa can explain 93.07% of the variability in METRIC ETa and 86.01% in the SSEBop Eta estimates. Both METRIC and SSEBop reflected the ETa of alfalfa during full growth and harvesting periods. However, the absolute percent mean relative difference (MRD) of ET was higher for two out of three cuttings by SSEBop (&gt;32%) compared to those for METRIC and eddy covariance. The spatiotemporal variabilities in crop ET estimates using METRIC and SSEBop showed a need to improve on-farm irrigation conveyance and on-the-field irrigation efficiency. Overall, RS models can provide spatiotemporal maps of ET that can be used for decision-making to manage irrigation water better and improve crop yield on a field, farm, and regional scale.

Floral Visitors of the Golden Rain Tree, Cassia fistula (Fabaceae), in Campeche, Mexico1

Abstract Cassia fistula L., known as the golden rain tree, is a flowering tree that is native to Asia but is used as an ornamental plant in public and private gardens in many areas of Mexico. It is also important for its antifungal, antibacterial, antioxidant, phytochemical, and medicinal properties. In this study, floral visitors of C. fistula were identified in the urban area of Escarcega, Campeche, Mexico in three public gardens during the month of May using entomologic nets. The insects were preserved with 70% alcohol, transported to the laboratory, and identified to species level using taxonomic keys. In total, 124 insects were collected representing 8 species belonging to 7 genera. Of those insects collected, Trigona fulviventris Guérin-Méneville and Trigona silvestriana Vachal (Hymenoptera: Apidae) were the most abundant, accounting for almost 50% of the total specimens collected. Previous reports list 32 species of insects as floral visitors of C. fistula in Mexico. Our study adds six species to that list that had not been previously recorded: Epicharis elegans Smith, Eulaema polychroma (Mocsáry), Melipona sp., T. silvestriana, and Xylocopa latipes (Drury), which are all members of the family Apidae (order Hymenoptera), and Parachartergus apicalis (F.), a vespid (Hymenoptera: Vespidae).

Analysis of Cadmium, Mercury and Lead in oysters (Crassostrea virginica) in a protected area of southeastern Mexico associated with the risk to human health

BackgroundMetal pollution is a problem in many parts of the world. These metals can be harmful when they exceed the recommended limits. This study aimed to assess the levels of cadmium (Cd), mercury (Hg), and lead (Pb) in the tissues of oysters (Crassostrea virginica) within a protected area in southeastern Mexico. Additionally, the study aimed to conduct a risk analysis for human health associated with these metals. It is anticipated that the observed metal levels will be lower compared to prior studies, thereby not posing a significant risk to the local population. MethodsThe tissue of oyster samples was treated under the techniques of the Official Mexican Standards and analyzed using atomic absorption spectroscopy. The metal concentrations were used to calculate the estimated daily intakes (EDI), target hazard quotients (THQ), hazard index (HI), and target cancer risks (TR), for children and adults. ResultsMaximum values of Cd (1.99 μg g−1), exceeded the permissible limits of the Official Mexican Standards. Pb (0.99 μg g−1) and Hg (0.64 μg g−1) are within the recommended limits. The THQ and HI for Cd, Pb, and Hg were lower than the United States Environmental Protection Agency (US-EPA) criteria. ConclusionsBased on our results, whether oyster (Crassostrea virginica) consumption is recommended in adults and reducing consumption in children; to diminish the risk of exposure to Cd, Pb, and Hg.