Metropolitan Area Of Monterrey Research Articles

Chemical Composition, Optical Properties and Sources of PM2.5 From a Highly Urbanized Region in Northeastern Mexico

Here, we report the chemical composition and optical properties of the fine particles (PM2.5) and water-soluble organic carbon (WSOC) of these particles. Additionally, the potential sources of WSOC emission were determined through the study on fluorescence excitation–emission matrix spectra and parallel factor analysis (EEM-PARAFAC). Samples were collected in an urban site of the Monterrey Metropolitan Area in Mexico during summer and winter and characterized using attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), ultraviolet-visible-near infrared-diffuse reflectance spectroscopy (UV–Vis-NIR-DRS), fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) techniques. The ATR-FTIR analyses allowed the identification of inorganic ions (e.g., CO32−, SO42−, and NO3−), organic functional groups [e.g., carbonyls (C=O), organic hydroxyl (C-OH), carboxylic acid (COOH)], and aromatic and unsaturated aliphatic hydrocarbons. The results obtained by XRD and XPS revealed the presence of organic and inorganic chemical species in PM2.5. The diffuse reflectance spectra of PM2.5 provided the absorption bands in the UV region for CaSO4, CaCO3, and aluminosilicates. The absorption coefficient at 365 nm (Abs365) and Ångström absorption exponent (AAE) values obtained for the aqueous extracts suggest that many of the water-soluble organic compounds corresponded to brown carbon (BrC) chromophores. The mass absorption efficiency values at 365 nm (MAE365) were higher in the winter than summer samples, suggesting the presence of more BrC compounds in the winter samples. The fluorescence indices combined with EEM-PARAFAC analysis showed that the WSOC fraction was mainly composed of humic-like substances (HULIS) which are both of terrestrial and microbial origin.

Extensive Wastewater-Based Epidemiology as a Resourceful Tool for SARS-CoV-2 Surveillance in a Low-to-Middle-Income Country through a Successful Collaborative Quest: WBE, Mobility, and Clinical Tests

The COVID-19 pandemic has challenged healthcare systems worldwide. Efforts in low-to-middle-income countries (LMICs) cannot keep stride with infection rates, especially during peaks. A strong international collaboration between Arizona State University (ASU), Tec de Monterrey (TEC), and Servicios de Agua y Drenaje de Monterrey (Local Water Utilities) is acting to integrate wastewater-based epidemiology (WBE) of SARS-CoV-2 in the region as a complementary approach to aid the healthcare system. Wastewater was collected from four sewer catchments in the Monterrey Metropolitan area in Mexico (pop. 4,643,232) from mid-April 2020 to February 2021 (44 weeks, n = 644). Raw wastewater was filtered and filter-concentrated, the RNA was extracted using columns, and the Charité/Berlin protocol was used for the RT-qPCR. The viral loads obtained between the first (June 2020) and second waves (February 2021) of the pandemic were similar; in contrast, the clinical cases were fewer during the first wave, indicating poor coverage. During the second wave of the pandemic, the SARS-CoV-2 quantification in wastewater increased 14 days earlier than the COVID-19 clinical cases reported. This is the first long-term WBE study in Mexico and demonstrates its value in pandemic management.

Woody plant community structure and composition of an urban riparian forest in Monterrey metropolitan area, Northeast Mexico1

This work details the structure and composition of the woody plant community of a gallery forest located in the La Silla River, between Monterrey and Guadalupe urban areas in Nuevo León, Mexico. For the analysis, the woody vegetation was categorized into upper and lower strata. The upper stratum maximum height was 38 m, and the canopy cover was 100%. The canopy consisted of 22 species from 16 families, of which seven species represented 82.3% of the importance value index (IV); Taxodium huegelii had the highest IV (34.32%). The lower stratum maximum height was 2.5 m, and the cover was 48%. Thirteen species from 10 families were identified, five of which reached 81.3% of the IV; Ricinus communis had the highest IV (23.42%). The plant community diversity was 3.8 and 2.29, based on Margalef and Shannon indices, respectively. As one finding in the present study, it can be stated that the main threat is the presence of widely distributed exotic species such as Ricinus communis and Leucaena leucocephala, with high importance values. However, the presence of a well-established tree stratum, as well as the presence of species typical of the gallery forest, suggest a good state of conservation of this gallery forest. The present results highlight the importance of studying the composition, structure, and diversity, taking into consideration the flora of floristic provinces, as an analytic strategy for the diagnosis of riparian lentic community health.

Neural Network and Spatial Model to Estimate Sustainable Transport Demand in an Extensive Metropolitan Area

Urban renewal projects worldwide focus mainly on resolving motorized, personal, and low occupancy problems instead of sustainable mobility. As part of the process, traditional field audits have a high cost in time and resources. This paper reviews a spatial model of accessibility and habitability of the streets, oriented to the location of the volume of people moving sustainably out of an extensive street network. The exercise site is in the Monterrey Metropolitan Area, the second largest in Mexico. Here, the population that moves sustainably as the collective (public and enterprise transportation) and the active (cycling, walking, and others) represents a considerable portion (49%) of travelers, thus, confirming the need for intervention. The spatial model is elaborated in a Geographical Information System (GIS), and the main results are compared with the actual public transport demand using a neural networks process. The results of the tool as a predictor have a 91% efficiency, making it possible to determine the location of urban renewal projects related to the volume of people moving sustainably.

Mobility and sustainable transportation in higher education: evidence from Monterrey Metropolitan Area in Mexico

PurposeThis paper aims to analyze the demand for mobility in higher education to understand the critical elements of students' mobility and the potential impact of accessing sustainable alternatives. The demand for different means of transportation accounts for socioeconomic variables such as household income and size, gender, age, among other travel factors such as distance, time, speed and direct cost.Design/methodology/approachThis research uses a unique data set encompassing a representative sample of households across gender and municipalities in the Monterrey Metropolitan Area in Mexico. This paper uses the value of transportation time savings approach to estimate the derived demand for mobility in higher education across different means. The empirical strategy uses a linear utility framework in a multinomial non-ordered logit model to analyze the conditional selection of transportation as a function of sociodemographics, direct monetary costs and travel determinants such as travel time, distance and speed.FindingsMen students are more likely to use an unsustained transportation mode such as a car or cab than women. Income is a crucial determinant for transportation demand. There is a negative relationship between household income and walking or riding the bus but positive with driving a car. An increase in the time of the trip decreases the probability of walking while increasing the likelihood of using a car or riding the bus to school. Students who feel safe while riding a bus are more likely to use the bus or walk as transportation than using a car. Finally, having access to better quality sidewalks significantly incentive walking over other transportation options.Practical implicationsResults show that individuals would almost always choose private vehicles because of the personal comforts and time savings.Social implicationsUnderstanding the demand for higher education and access to sustainable transportation might provide new insights into campus planning and development. Access to public transportation options can reduce the travel costs for students with lower incomes and enlarge options for students who have to commute longer distances by car. Sustainable transportation access plays a role in promoting equality and economic development.Originality/valueThis study’s results bring new light on how transportation becomes an essential component of the opportunity cost of college education and could define its role in promoting equality or increasing inequality. This study’s finding is of particular interest for cities where housing location seems to be independent of access to school, work or other amenities.

FINE PARTICLES EMISSION SOURCE PROFILES FOR A SEMI-ARID URBAN CENTER: KEY MARKERS AND SIMILARITY TESTS

Source apportionment studies rely on source emission profiles, which in some instances are locally scarce or non-existent. Thus, estimations are done using profiles obtained from other geographical sites, which brings a certain degree of uncertainty in the outcomes of such studies. This work presents the results of near-field measurement of 12 types of fine particle emission sources to develop local-region source profiles in the Monterrey Metropolitan Area. The source profiles include a chemical characterization of trace elements and carbonaceous fraction. A statistical analysis based on the Pearson distance and similarity identity distance was conducted to ensure the uniqueness of each source profile. Overall, the most dominant species in the profiles were organic and elemental carbon, and elemental sulfur, whereas the least abundant were transition metals. The meat-cooking operations profiles exhibited the highest organic carbon to elemental carbon ratios, which were 7-40 times higher than those for biomass burning and vehicle exhausts profiles. The urban construction profile was dominated by crustal elements, while the suburban area profile exhibited an internal mixing with anthropogenic compounds. The source profiles in this study were distinguishable, as determined by preliminary tests for each pair of chemical source profiles. These profiles could be used to implement receptor models in urban sites with similar characteristics.

Levels of Aflatoxin M1 in Breast Milk of Lactating Mothers in Monterrey, Mexico: Exposure and Health Risk Assessment of Newborns.

The present study aimed to determine the presence of the aflatoxin M1 (AFM1) in breast milk samples from 123 nursing women and the degree of exposure of infants to this toxin, in the metropolitan area of Monterrey, Nuevo Leon state (northeast Mexico). Upon analysis, 100% of the samples were found to be contaminated with the toxin at an average concentration of 17.04 ng/L, with a range of 5.00 to 66.23 ng/L. A total of 13.01% of the breast milk samples exceeded the regulatory limit of 25 ng/L for AFM1 concentration, set by the European Union. The estimated daily intake for AFM1 and the carcinogenic risk index were also determined in the 0- to 6-, 7- to 12-, 13- to 24-, and 25- to 36-month-old age groups. The AFM1 intake through breast milk ranged from 1.09 to 20.17 ng/kg weight/day, and was higher than the tolerable daily intake, indicating a carcinogenic risk for infants in the age groups of 0- to 24-months old. This evidence demonstrates a susceptibility of breast milk to AFM1 contamination that may suggest a carcinogenic risk for the breastfed infants in Monterrey city, Nuevo Leon state, and the need to control the presence of aflatoxins in foods eaten by nursing mothers.

Acquired insights from the long-term surveillance of SARS-CoV-2 RNA for COVID-19 monitoring: The case of Monterrey Metropolitan Area (Mexico)

Wastewater-based epidemiology offers a time- and cost-effective way to monitor SARS-CoV-2 spread in communities and therefore represents a complement to clinical testing. WBE applicability has been demonstrated in a number of cases over short-term periods as a method for tracking the prevalence of SARS-CoV-2 and an early-warning tool for predicting outbreaks in the population. This study reports SARS-CoV-2 viral loads from wastewater treatment plants (WWTPs) and hospitals over a 6-month period (June to December 2020). Results show that the overall range of viral load in positive tested samples was between 1.2 × 103 and 3.5 × 106 gene copies/l, unveiling that secondary-treated wastewaters mirrored the viral load of influents. The interpretation suggests that the viral titers found in three out of four WWTPs were associated to clinical COVID-19 surveillance indicators preceding 2–7 days the rise of reported clinical cases. The median wastewater detection rate of SARS-CoV-2 was one out of 14,300 reported new cases. Preliminary model estimates of prevalence ranged from 0.02 to 4.6% for the studied period. This comprehensive statistical and epidemiological analysis demonstrates that the applied wastewater-based approach to COVID-19 surveillance is in general consistent and feasible, although there is room for improvements.

Experimental analysis of real-world emissions using ultra-low carbon intensity biodiesel for a light-duty diesel vehicle in Monterrey metropolitan area

Experiments were conducted employing a light-duty diesel vehicle filled with complete characterized 5%, 10%, and 20% volume ultra-low carbon intensity waste cooking oil biodiesel blends for determining real-world emission rates and emission factors, which were compared to those of petroleum diesel for three driving modes, namely, low, medium, and high cruise speed, and transient conditions. Chemical characterization of blended and pure fuels allowed to discard any quality influences on the fuel performance during the on-road tests. Five percent volume blends showed the best all-around performance of all blends in comparison with petroleum diesel in terms of emissions reduction, along with its lowest fuel consumption, hence, representing a potential blend that can be considered as good additive for petroleum diesel, applicable only at the specific conditions of the present work. The benefit from the use of ultra-low carbon intensity biodiesel blends was clear from greenhouse gases emissions point of view, given the lifecycle emission diminishing of 93.8% mass in CO2 equivalent emissions, if the biodiesel is produced using waste cooking oil collected within the city limits.

Statistical Analysis of PM10 Concentration in the Monterrey Metropolitan Area, Mexico (2010–2018)

Air-quality monitoring and analysis are initial parts of a comprehensive strategy to prevent air pollution in cities. In such a context, statistical tools play an important role in determining the time-series trends, locating areas with high pollutant concentrations, and building predictive models. In this work, we analyzed the spatio-temporal behavior of the pollutant PM10 in the Monterrey Metropolitan Area (MMA), Mexico during the period 2010–2018 by applying statistical analysis to the time series of seven environmental stations. First, we used experimental variograms and scientific visualization to determine the general trends and variability in time. Then, fractal exponents (the Hurst rescaled range and Higuchi algorithm) were used to analyze the long-term dependence of the time series and characterize the study area by correlating that dependence with the geographical parameters of each environmental station. The results suggest a linear decrease in PM10 concentration, which showed an annual cyclicity. The autumn-winter period was the most polluted and the spring-summer period was the least. Furthermore, it was found that the highest average concentrations are located in the western and high-altitude zones of the MMA, and that average concentration is related in a quadratic way to the Hurst and Higuchi exponents, which in turn are related to some geographic parameters. Therefore, in addition to the results for the MMA, the present paper shows three practical statistical methods for analyzing the spatio-temporal behavior of air quality.

Motivation as a Driver of Customer Service: The Impact on Automobile Dealerships

The objective of the research is to analyze the relationship of Motivation as a soft skill that drives Customer Service in car dealerships, specifically in sales area employees. The survey was applied to a sample of 81 managers from the sales area of automotive agencies in the Monterrey metropolitan area. The proposed model was linear regression. The surveys were processed with SPSS Statistics. The hypothesis was confirmed, about the positive and significant relationship of the predictor variable and the dependent variable, in the employees of the sales area in the automobile agencies. It is suggested to analyze and build a complementary profile of the necessary soft skills of sales collaborators in car dealerships and other sectors.

Motivation as a Driver of Customer Service: The Impact on Automobile Dealerships

The objective of the research is to analyze the relationship of Motivation as a soft skill that drives Customer Service in car dealerships, specifically in sales area employees. The survey was applied to a sample of 81 managers from the sales area of automotive agencies in the Monterrey metropolitan area. The proposed model was linear regression. The surveys were processed with SPSS Statistics. The hypothesis was confirmed, about the positive and significant relationship of the predictor variable and the dependent variable, in the employees of the sales area in the automobile agencies. It is suggested to analyze and build a complementary profile of the necessary soft skills of sales collaborators in car dealerships and other sectors.

Motivation as a Driver of Customer Service: The Impact on Automobile Dealerships

The objective of the research is to analyze the relationship of Motivation as a soft skill that drives Customer Service in car dealerships, specifically in sales area employees. The survey was applied to a sample of 81 managers from the sales area of automotive agencies in the Monterrey metropolitan area. The proposed model was linear regression. The surveys were processed with SPSS Statistics. The hypothesis was confirmed, about the positive and significant relationship of the predictor variable and the dependent variable, in the employees of the sales area in the automobile agencies. It is suggested to analyze and build a complementary profile of the necessary soft skills of sales collaborators in car dealerships and other sectors.

Jóvenes y colectivos en barrios marginales de Monterrey: aproximaciones a la contingencia de vida y precarización de sí

The article analyzes the perceptions of young men and women who intervene in popular and marginal enclaves of the Monterrey metropolitan area, by means of educational and art projects. Conceptually I refer to them as cultural producers as they imagine their own autonomous production. This process, expressed in different modes of subjectivation, is also an instrument that constitutes functional effects of the biopolitical governmentality of western societies. The young members of the collectives go through a variety of aspects with their actions, such as political and cultural self-organization, forms of collaboration, and paid employment. The approach is based on the “contingency of life”, and the “precariousness of oneself” as ambivalent forms of self-government that oscillate between self-exploitation and modes of subjectivation, from which these groups perceive the risks and opportunities of the city as actionable and moldable.

Epidemiological characterization of influenza in Northern Mexico

Influenza viruses cause a potentially fatal, highly contagious respiratory disease. Influenza A virus subtypes H1N1 and H3N2, and both lineages of the influenza B virus have affected the Mexican population. The present study aimed to determine the epidemiological characteristics of influenza infections in Northern Mexico during five flu seasons and determines the risk factors for hospitalization. For this purpose, 3,482 patients with confirmed influenza infection tested at the Public Health State Laboratory of Nuevo León using reverse transcription‑quantitative PCR from October, 2009 to December, 2014 were evaluated. Patient demographics and clinical characteristics were determined, and data were collected and analyzed. Pandemic influenza A H1N1 subtype was responsible for 52% of the cases in the present study; the influenza A H3N2 subtype was responsible for 27% of cases and the influenza B virus for 12% of cases. In total, 75% of the patients (n=2,611) received ambulatory treatment and 25% (n=871) were hospitalized. The number of hospitalized patients varied across the different seasons analyzed. A greater number of comorbidities were observed in hospitalized patients than the ambulatory patients; 64% of patients with chronic obstructive pulmonary disease (COPD), 60% of patients with chronic kidney disease, and 51% of patients with diabetes were hospitalized. Of the total number of vaccinated patients, only 18% were hospitalized, in contrast to 27% of unvaccinated patients. On the whole, the present study describes the influenza cases identified in the metropolitan area of Monterrey, Mexico. The median age and clinical characteristics of the patients varied according to the season with increasing age, and the presence of dyspnea, polypnea, cyanosis, malaise, COPD, diabetes, or no vaccination, were associated with an increased risk of hospitalization. This clinical characterization becomes relevant as coronavirus 2019 spreads worldwide, rendering its differential diagnosis necessary in respiratory diseases that usually lead to hospitalization, such as influenza.

Association between Bone Mineral Density and Metabolic Syndrome among Reproductive, Menopausal Transition, and Postmenopausal Women.

The menopausal transition stage brings physiological changes associated with the development of metabolic syndrome (MetS), which can affect bone mineral density (BMD), and may be more evident in the postmenopausal stage. The aim of this study was assessing the association between low BMD and MetS and its components among reproductive/menopausal transition and postmenopausal women in the northeast region of Mexico. A descriptive cross-sectional study was carried out (2015–2016) in 40–60-year-old women (n = 376) who were residents in the metropolitan area of Monterrey, in Nuevo Leon State, Mexico. Anthropometric measurements, blood pressure, a dual-energy X-ray absorptiometry (DXA) evaluation of BMD of two anatomical sites (lumbar spine and dual femur), and a biochemical analysis were obtained. The prevalence of MetS was 57.2%. In participants without MetS, the prevalence of osteopenia was 27.3% in the lumbar spine and 18.6% in the dual femur, while in participants with MetS, the prevalence of osteopenia was 35.8% in the lumbar spine and 14.4% in the dual femur. Osteoporosis in participants without MetS was present in 6.8% in the lumbar spine and in 1.8% in the dual femur, while in women with MetS, its prevalence was 4.7% in the lumbar spine and 0.5% in the dual femur. An association between low BMD at the lumbar spine and dual femur and components of MetS diseases was identified in Mexican women as follows: waist circumference ≥ 88 cm showed an increase risk for low BMD at femoral site in both reproductive/menopausal transition (OR 7.638; 95% CI: 1.607–36.298; p = 0.011) and postmenopausal women (OR 2.600; 95% CI: 1.023–6.609; p = 0.045); HDL < 50 mg/dL was associated with low BMD in both the femur (OR 3.639; 95% CI: 1.039–12.743; p = 0.043) and lumbar spine (OR 2.654; 95% CI: 1.092–6.447; p = 0.031); hypertension in postmenopausal women increased the risk for low BMD in the femur (OR 2.634; 95% CI: 1.150–6.035; p = 0.022). In conclusion, we found that components of the MetS were associated with low BMD, thus indicating that MetS increases the risk for developing osteopenia or osteoporosis. Furthermore, age was found to be an independent risk factor for low BMD.

Emprendimiento de nanoempresas en el empoderamiento de mujeres neolonesas

This paper analyzes the relationship between nano-business entrepreneurship and women’s empowerment. The authors applied a controlled laboratory experiment with 204 participants from October 2017 to March 2018 in the Metropolitan Area of Monterrey. The method they used was a decision matrix and a logit model that allow them to obtain estimations of the entrepreneurs’ decisions on their empowerment. Among the main findings of this paper, it is found that nano-business entrepreneurship has a positive and significant impact on female empowerment through more economic opportunities and self-confidence.

Short-Term Associations between Morbidity and Air Pollution in Metropolitan Area of Monterrey, Mexico

Short-term effects of air pollution on the number of hospital admissions in eight municipalities of the Metropolitan Area of Monterrey, Mexico, were assessed from 2016 to 2019 using a time-series approach. Air quality data were obtained from the Atmospheric Monitoring System of Nuevo Leon State (SIMA) which belongs to SINAICA (National System of Air Quality Information), providing validated data for this study. Epidemiological data were provided by SINAIS (National System of Health Information), considering admission by all causes and specific causes, gender and different age groups. Guadalupe had the highest mean concentrations for SO2, CO and O3; whereas Santa Catarina showed the highest NO2 concentrations. Escobedo and Garcia registered the highest levels for PM10. Only PM10 and O3 exceeded the permissible maximum values established in Mexican official standards. A basal Poisson model was constructed to assess the association between daily morbidity and air pollutants, from this, a second scenario in which daily mean concentrations of air pollutant criteria increase by 10% was considered. Most of pollutants and municipalities studied showed a great number of associations between an increase of 10% in their current concentrations and morbidity, especially for the age group between 5 and 59 years during cold months, excepting ozone which showed a strongest correlation during summer. Results were comparable to those reported by other authors around the world, however, in spite of relative risk index (RRI) values being low, they are of public concern. This study demonstrated that considering the nature of their activities, economically active population and students, they could be more vulnerable to air pollution effects. Results found in this study can be used by decision makers to develop public policies focused on protecting this specific group of the population in metropolitan areas in Mexico.

The Lives of the Accordion. Repairers and Social Life of a Musical Instrument in Monterrey

This article explores the practices and meanings surrounding the trade of an accordion repairer in the metropolitan area of Monterrey, Mexico, using the cultural studies of the musical instrument and the anthropology and sociology of the craft. It describes the diversity and diversity of services offered under the term “repair” and highlights the amount and variety of knowledge needed to maintain or embellish this “sound machine”. Likewise, it describes the different paths towards obtaining and updating them. In these processes, one can, at times, identify the typical abilities of a technician, and other times, of a craftsperson; abilities conditioned, although not determined, by the global manufacturing and marketing processes of this instrument.

Spatial interaction between breast cancer and environmental pollution in the Monterrey Metropolitan Area

This research examines the spatial structure of a sample of breast cancer (BC) cases and their spatial interaction with contaminated areas in the Monterrey Metropolitan Area (MMA). By applying spatial statistical techniques that treat the space as a continuum, degrees of spatial concentration were determined for the different study groups, highlighting their concentration pattern. The results indicate that 65 percent of the BC sample had exposure to more than 56 points of PM10. Likewise, spatial clusters of BC cases of up to 39 cases were identified within a radius of 3.5 km, interacting spatially with environmental contamination sources, particularly with refineries, food processing plants, cement, and metals. This study can serve as a platform for other clinical research by identifying geographic clusters that can help focus health policy efforts.