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Sample records for mexico city subsidence

  1. Subsidence Induced Faulting Hazard risk maps in Mexico City and Morelia, central Mexico

    NASA Astrophysics Data System (ADS)

    Cabral-Cano, E.; Solano-Rojas, D.; Hernández-Espriu, J.; Cigna, F.; Wdowinski, S.; Osmanoglu, B.; Falorni, G.; Bohane, A.; Colombo, D.

    2012-12-01

    Subsidence and surface faulting have affected urban areas in Central Mexico for decades and the process has intensified as a consequence of urban sprawl and economic growth. This process causes substantial damages to the urban infrastructure and housing structures and in several cities it is becoming a major factor to be considered when planning urban development, land use zoning and hazard mitigation strategies in the next decades. Subsidence is usually associated with aggressive groundwater extraction rates and a general decrease of aquifer static level that promotes soil consolidation, deformation and ultimately, surface faulting. However, local stratigraphic and structural conditions also play an important role in the development and extension of faults. Despite its potential for damaging housing, and other urban infrastructure, the economic impact of this phenomena is poorly known, in part because detailed, city-wide subsidence induced faulting risk maps have not been published before. Nevertheless, modern remote sensing techniques are most suitable for this task. We present the results of a risk analysis for subsidence induced surface faulting in two cities in central Mexico: Morelia and Mexico City. Our analysis in Mexico City and Morelia is based on a risk matrix using the horizontal subsidence gradient from a Persistent Scatterer InSAR (Morelia) and SqueeSAR (Mexico City) analysis and 2010 census population distribution data from Mexico's National Institute of Statistics and Geography. Defining subsidence induced surface faulting vulnerability within these urbanized areas is best determined using both magnitude and horizontal subsidence gradient. Our Morelia analysis (597,000 inhabitants with localized subsidence rates up to 80 mm/yr) shows that 7% of the urbanized area is under a high to very high risk level, and 14% of its population (11.7% and 2.3% respectively) lives within these areas. In the case of the Mexico City (15'490,000 inhabitants for the

  2. Differential subsidence in Mexico City and implications to its Collective Transport System (Metro).

    NASA Astrophysics Data System (ADS)

    Solano Rojas, D. E.; Wdowinski, S.; Cabral-Cano, E.; Osmanoglu, B.

    2017-12-01

    Mexico City is one of the fastest subsiding metropolis in the world. At displacement rates ranging from 0 to -380 [mm/yr], the complex geological setting is subjected to differential subsidence, which has led to damage, operation interruptions, and accidents to the Collective Transport System, or Metro. The Metro plays a critical role in Mexico City, carrying more than four million passengers per day. However, no previous study has focused on the deformation monitoring along the 93 km of the Metro surface railways, mainly because of the limitations of the traditional geodetic techniques. In this study, we use high-resolution Interferometric Synthetic Aperture Radar (InSAR) observations to monitor land subsidence throughout the city and quantify differential subsidence along surface Metro lines. Our analysis is based on 34 TerraSAR-X StripMap scenes acquired from May 2011 to June 2013 and 36 COSMO-SkyMed Stripmap scenes acquired from June 2011 to June 2012. The data were processed using the StaMPS InSAR time series technique, obtaining point densities of up to 4827 points/km2. Our post-processing methodologies include the following two components: (1) Detection of differential subsidence along the metro lines by calculating subsidence gradients, and (2) Detection of apparent uplift—areas subsiding slower than their surroundings—by using spatial frequency filtering. The two analyses allow us to recognize four main consequences of differential subsidence in the Metro system: 1. Deflection in elevated railways, 2. Deflection in street-level railways, 3. Columns with decreased loading capacity, and 4. Apparent uplift affecting surrounding infrastructure. Our results aim at shortening the large gap between scientific geodetic studies and applicable engineering parameters that can be used by local authorities in the city for maintenance and new lines development.

  3. Differential Subsidence in Mexico City and its Consequences to the Collective Transport System (Metro)

    NASA Astrophysics Data System (ADS)

    Solano Rojas, D. E.; Wdowinski, S.; Cabral, E.; Zhang, Y.; Torres, Y.

    2015-12-01

    Mexico City is one of the most populated metropolitans in the world, with more than 20 millions inhabitants. It is located above a sequence of deformable unconsolidated lacustrine sediments interlayered with strong volcanic rocks. These natural conditions combined with massive groundwater extraction, caused the city to subside unevenly, at rates from 0 to ~370 mm/yr, which we term differential subsidence. Our study focuses on the Collective Transport System (Metro), the massive, widely used transportation system in the city. It has been in operation since 1969. The Metro system carries an average of more than four million passengers per day along its 218 km of railways. This system has been occasionally damaged by ground deformation, in particular Line 12, in which 50% of its stations where shut down just 2.5 years after the beginning of its operation due to faults, "waves" and "bumps" along the line. In this study we used Interferometric Synthetic Aperture Radar (InSAR) observations to monitor land subsidence throughout the city and infer differential subsidence along the main Metro lines. Our analysis is based on 34 TerraSAR-X and 36 COSMO-SkyMed high-resolution scenes acquired from mid 2011 to mid 2013. The data were processed using the StaMPS InSAR time series technique, which calculates ground displacement time series for more than 2.5 million selected measurement points, typically separated 3-15 meters apart. The differential subsidence along the Metro lines was calculated by averaging subsidence rate within a 30 m radius circles, every 60 m along the lines. We found that the segments with the most differential deformation are in lines 4, 5, 9, A, B and 12. Our easy-to-implement method can be applied to permanent monitor deformation along the railways, as well as serve as a guide for the development of new lines of the Metro system prospected by Mexico's City government.

  4. Time series analysis of Mexico City subsidence constrained by radar interferometry

    NASA Astrophysics Data System (ADS)

    Doin, Marie-Pierre; Lopez-Quiroz, Penelope; Yan, Yajing; Bascou, Pascale; Pinel, Virginie

    2010-05-01

    In Mexico City, subsidence rates reach up to 40 cm/yr mainly due to soil compaction led by the over exploitation of the Mexico Basin aquifer. The Mexico Valley, an endoreic basin surrounded by mountains, was in the past covered by large lakes. After the Spanish conquest, the lakes have almost completely disappeared, being progressively replaced by buildings of the current Mexican capital. The simplified hydrogeologic structure includes a superficial 50 to 300 m thick lacustrine aquitard overlying a thicker aquifer made of alluvial deposits. The aquitard layer plays a crucial role in the subsidence process due to the extremely high compressibility of its clay deposits separated by a less compressible sand layer where the biggest buildings of the city are anchored. The aquifer over-exploitation leads to a large scale 30m depression of its piezometric level, inducing water downwards flow in the clays, yielding compaction and subsidence. In order to quantitatively link subsidence to water pumping, the Mexico city subsidence needs to be mapped and analyzed through space and time. We map its spatial and temporal patterns by differential radar interferometry, using 38 ENVISAT images acquired between end of 2002 and beginning of 2007. We employ both a Permanent Scatterer (PS) and a small baseline (SBAS) approach. The main difficulty consists in the severe unwrapping problems mostly due to the high deformation rate. We develop a specific SBAS approach based on 71 differential interferograms with a perpendicular baseline smaller than 500 m and a temporal baseline smaller than 9 months, forming a redundant network linking all images: (1) To help the unwrapping step, we use the fact that the deformation shape is stable for similar time intervals during the studied period. As a result, a stack of the five best interferograms can be used to reduce the number of fringes in wrapped interferograms. (2) Based on the redundancy of the interferometric data base, we quantify the

  5. The Subsidence Signature Due To Groundwater Extraction as Inferred from Remote Sensing Data in Mexico City

    NASA Astrophysics Data System (ADS)

    Patel, V.; Chen, J.

    2015-12-01

    Mexico City is facing a severe water shortage; current drought conditions in the city have led to an increase in the demand for groundwater, the pumping of which can cause significant land subsidence. In this study we explored what new information interferometric synthetic aperture radar (InSAR) data collected by the TerraSAR-X satellite could bring to water resource managers in the city so that they can efficiently and sustainably allocate water resources. Previous work done over Mexico City indicates that InSAR can be used to detect deformation due to groundwater pumping. Cabral-Cano et al. (2008) processed InSAR data acquired from ERS between 1996-2000 and from ENVISAT between 2003-2005. They compared the deformation map to geology maps of the region with information obtained by seismic methods. They found that a spatial correlation between the land deformation and the presence of young lacustrine clay beds, which indicate that the subsidence was caused by fluid pressure loss in the aquitard. They also concluded that the subsidence, for the most part, had no seasonal variation and continues to occur at near-constant, high rates. TerraSAR-­X satellite data is known to be more sensitive to small deformations than the data from satellites used in previous studies in the region because of its frequent revisit cycle, short wavelength, and accurate orbital information. For this project, we derived long sequences of crustal deformation time series from TerraSAR-­X data between May 2011 and December 2012 using the Small Baseline Subset (SBAS) method. The resulting time series was then compared to GPS data for calibration and validation. We observed a long-term deformation that was similar to those found in previous studies. The next step in our work is to determine whether the increased sensitivity of the TerraSAR-­X data allows us to detect a seasonal deformation pattern over the study area.

  6. Time series analysis of Mexico City subsidence constrained by radar interferometry

    NASA Astrophysics Data System (ADS)

    López-Quiroz, Penélope; Doin, Marie-Pierre; Tupin, Florence; Briole, Pierre; Nicolas, Jean-Marie

    2009-09-01

    In Mexico City, subsidence rates reach up to 40 cm/yr mainly due to soil compaction led by the over exploitation of the Mexico Basin aquifer. In this paper, we map the spatial and temporal patterns of the Mexico City subsidence by differential radar interferometry, using 38 ENVISAT images acquired between end of 2002 and beginning of 2007. We present the severe interferogram unwrapping problems partly due to the coherence loss but mostly due to the high fringe rates. These difficulties are overcome by designing a new methodology that helps the unwrapping step. Our approach is based on the fact that the deformation shape is stable for similar time intervals during the studied period. As a result, a stack of the five best interferograms can be used to compute an average deformation rate for a fixed time interval. Before unwrapping, the number of fringes is then decreased in wrapped interferograms using a scaled version of the stack together with the estimation of the atmospheric phase contribution related with the troposphere vertical stratification. The residual phase, containing less fringes, is more easily unwrapped than the original interferogram. The unwrapping procedure is applied in three iterative steps. The 71 small baseline unwrapped interferograms are inverted to obtain increments of radar propagation delays between the 38 acquisition dates. Based on the redundancy of the interferometric data base, we quantify the unwrapping errors and show that they are strongly decreased by iterations in the unwrapping process. A map of the RMS interferometric system misclosure allows to define the unwrapping reliability for each pixel. Finally, we present a new algorithm for time series analysis that differs from classical SVD decomposition and is best suited to the present data base. Accurate deformation time series are then derived over the metropolitan area of the city with a spatial resolution of 30 × 30 m.

  7. Ert Applied to the Characterization of Subsidence in Mexico City: Ancient Structures Affecting Urban Utilities

    NASA Astrophysics Data System (ADS)

    Arango, C.; Chavez, R. E.; Cifuentes-Nava, G.; Hernández-Quintero, E.

    2013-05-01

    The problem of subsidence in Mexico City is basically due to the rapid extraction of groundwater for water supply in addition to the geological conditions. The most typical manifestations of the phenomena are presented as cracks and fractures due to compaction of ancient lake clayish sediments. This phenomenon has caused major affectations to city infrastructure because of the differential subsidence. Fractured buildings, sinkholes, among others manifestations, are potentially sources of collapses, which exposes the population to a serious risk. A small portion of Iztacalco County is being affected by this problem, specifically, in a crossroad formed by two important avenues: La Viga and Plutarco Elias Calles, where the area apparently increases its topographical level. The Electrical Resistivity Tomography technique was selected in order to obtain a resistivity image of the subsoil, which allows identify the main features associated to the terrain uprising. Three (ERT) profiles 200 m, were deployed on the mentioned crossroad in order to characterize the subsurface structures affecting the topographical level of the avenues. A big resistivity anomaly (~ 1000 ohm-m) could be observed towards the central part of the crossroad, coinciding with the major lifting level on surface. This feature appears at 15 m deep in all the profiles and depicts an approximate extension of 100 m in the E-W direction and 60 m in N-S axis. On the other hand, the surrounding material seems to correspond to a higher-saturated environment (lacustrine sediments <10 ohm-m). Shallow anomalies were also detected related to urban artifacts (pipes, sewers, etcetera). The apparently terrain uprising can be associated to a differential subsidence. However, the mentioned avenues were ancient water channels since pre-Hispanic times, where the caudal was enough to allow small steam boating at late nineteenth century. These waterways served as main routes for the exchange of goods during colonial times

  8. Development of an expert analysis tool based on an interactive subsidence hazard map for urban land use in the city of Celaya, Mexico

    NASA Astrophysics Data System (ADS)

    Alloy, A.; Gonzalez Dominguez, F.; Nila Fonseca, A. L.; Ruangsirikulchai, A.; Gentle, J. N., Jr.; Cabral, E.; Pierce, S. A.

    2016-12-01

    Land Subsidence as a result of groundwater extraction in central Mexico's larger urban centers initiated in the 80's as a result of population and economic growth. The city of Celaya has undergone subsidence for a few decades and a consequence is the development of an active normal fault system that affects its urban infrastructure and residential areas. To facilitate its analysis and a land use decision-making process we created an online interactive map enabling users to easily obtain information associated with land subsidence. Geological and socioeconomic data of the city was collected, including fault location, population data, and other important infrastructure and structural data has been obtained from fieldwork as part of a study abroad interchange undergraduate course. The subsidence and associated faulting hazard map was created using an InSAR derived subsidence velocity map and population data from INEGI to identify hazard zones using a subsidence gradient spatial analysis approach based on a subsidence gradient and population risk matrix. This interactive map provides a simple perspective of different vulnerable urban elements. As an accessible visualization tool, it will enhance communication between scientific and socio-economic disciplines. Our project also lays the groundwork for a future expert analysis system with an open source and easily accessible Python coded, SQLite database driven website which archives fault and subsidence data along with visual damage documentation to civil structures. This database takes field notes and provides an entry form for uniform datasets, which are used to generate a JSON. Such a database is useful because it allows geoscientists to have a centralized repository and access to their observations over time. Because of the widespread presence of the subsidence phenomena throughout cities in central Mexico, the spatial analysis has been automated using the open source software R. Raster, rgeos, shapefiles, and rgdal

  9. Magnitude and extent of land subsidence in central Mexico revealed by regional InSAR ALOS time-series survey

    NASA Astrophysics Data System (ADS)

    Chaussard, E.; Wdowinski, S.; Amelung, F.; Cabral-Cano, E.

    2013-05-01

    Massive groundwater extraction is very common in Mexico and is well known to result in land subsidence. However, most surveys dedicated to land subsidence focus on one single city, mainly Mexico City, and thus fail to provide a comprehensive picture of the problem. Here we use a space-based radar remote sensing technique, known as Interferometric Synthetic Aperture Radar (InSAR) to detect land subsidence in the entire central Mexico area. We used data from the Japanese satellite ALOS, processed over 600 SAR images acquired between 2007-2011 and produced over 3000 interferograms to cover and area of 200,000 km2 in central Mexico. We identify land subsidence in twenty-one areas, including seventeen cities, namely from east to west, Puebla, Mexico city, Toluca de Lerdo, Queretaro, San Luis de la Paz, south of San Luis de la Paz, Celaya, south of Villa de Reyes, San Luis Potosi, west of Villa de Arista, Morelia, Salamanca, Irapuato, Silao, Leon, Aguascalientes, north of Aguascalientes, Zamora de Hidalgo, Guadalajara, Ahuacatlan, and Tepic. Subsidence rates of 30 cm/yr are observed in Mexico City, while in the other locations typical rates of 5-10 cm/yr are noticed. Regional surveys of this type are necessary for the development of hazard mitigation plans and efficient use of ground-based monitoring. We additionally correlate subsidence with land use, surface geology, and faults distribution and suggest that groundwater extraction for agricultural, urban, and industrial uses are the main causes of land subsidence. We also reveal that the limits of the subsiding areas often correlate with existing faults, motion on these faults being driven by water extraction rather than by tectonic activity. In all the subsiding locations we observe high ground velocity gradients emphasizing the significant risks associated with land subsidence in central Mexico. Averaged 2007-2011 ground velocity map from ALOS InSAR time-series in central Mexico, revealing land subsidence in 21

  10. An Integrated Assessment Framework for land subsidence in Delta cities

    NASA Astrophysics Data System (ADS)

    Bucx, T.; van Ruiten, K.; Erkens, G.

    2013-12-01

    In many delta cities land subsidence exceeds absolute sea level rise up to a factor of ten. Without change, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other delta (and coastal) cities will sink below sea level. Increased flooding and also other wide¬spread impacts of land subsidence result already in damage of billions of dollars per year to roads, embankments, subsurface infrastructure and housing. Moreover the potential damage caused by increased flood risk is around the same amount of money. A major cause for severe land subsidence is excessive groundwater extraction related to rapid urbanization and population growth. A major rethink is needed to resolve the ';hidden' but urgent threat of subsidence in a multi-sectoral perspective. A comprehensive approach is presented to address land subsidence for more sustainable and resilient urban development. Land subsidence is an issue that involves many policy fields, complex technical aspects and governance. There is a need for an integrated approach in order to manage subsidence and to develop appropriate strategies and measures that are effective and efficient on both the short and long term. Urban (ground)water management, adaptive flood risk management and related spatial planning strategies should be taken into account. This presentation will introduce and illustrate an Integrated Assessment Framework (IAF) for land subsidence that has been developed in the European FP7 project Subcoast. This framework is based on an integrated (multi-sectoral) approach and can be used to gain insight in the complex aspects of subsidence, to raise awareness and to support decision making on appropriate adaptation strategies and measures. The IAF is addressing all aspects of subsidence: from primary causes, vulnerability, impacts and risks towards responses and solutions. It will also take into account the three spatial layers (Occupation, Network and Base layer), governance aspects and several scenarios (economic

  11. Is There a Tectonic Component On The Subsidence Process In Morelia, Mexico?

    NASA Astrophysics Data System (ADS)

    Cabral-Cano, E.; Arciniega-Ceballos, A.; Diaz-Molina, O.; Garduno-Monroy, V.; Avila-Olivera, J.; Hernández-Madrigal, V.; Hernández-Quintero, E.

    2009-12-01

    Subsidence and faulting have affected cities in central Mexico for decades. This process causes substantial damages to the urban infrastructure, housing and large buildings, and is an important factor to be consider when planning urban development, land use zoning and hazard mitigation strategies. In Mexico, studies using InSAR and GPS based observations have shown that high subsidence areas are usually associated with the presence of thick lacustrine and fluvial deposits. In most cases the subsidence is closely associated with intense groundwater extraction that results in sediment consolidation. However, recent studies in the colonial city of Morelia in central Mexico show a different scenario, where groundwater extraction cannot solely explain the observed surface deformation. Our results indicate that a more complex interplay between sediment consolidation and tectonic forces is responsible for the subsidence and fault distribution within the city. The city of Morelia has experienced fault development recognized since the 80’s. This situation has led to the recognition of 9 NE-SW trending faults that cover most of its urbanized area. Displacement maps derived from differential InSAR analysis show that the La Colina fault is the highest subsiding area in Morelia with maximum annual rates over -35 mm/yr. However, lithological mapping and field reconnaissance clearly show basalts outcropping this area of high surface deformation. The subsurface characterization of the La Colina fault was carried out along 27 Ground Penetrating Radar (GPR) sections and 6 seismic tomography profiles. Assuming a constant, linear past behavior of the subsidence as observed by InSAR techniques, and based on the interpretation of the fault dislocation imaged by the shallow GPR and seismic tomography, it is suggested that the La Colina fault may have been active for the past 220-340 years and clearly pre-dates the intense water well extraction from the past century. These conditions

  12. [Migration to metropolitan Mexico City].

    PubMed

    Cantu Gutierrez, J J; Luque Gonzalez, R

    1990-01-01

    Accelerated urbanization, especially after 1940, has been among the great transformations in Mexico associated with rapid and sustained economic growth during 1950-80. The urbanization process was highly selective, favoring in particular Mexico City, Guadalajara, and Monterey, which together contain about 25% of Mexico¿s total population. Metropolitan Mexico City alone contained around 18.2% of the total 1990 population on 0.2% of Mexico¿s land area. Mexico City¿s population grew at an average annual rate of 4.2%, from 1.6 million in 1940 to 14.8 million in 1990, largely due to in-migration. Migrants and their reproduction are estimated to have accounted for 51.2% of Mexico City¿s growth since 1940, and physical expansion of the metropolitan zone for another 5.7%. Slightly over 80% of migrants come from 10 states that are mostly rural, relatively densely populated, not distant, and below average in living levels. Women predominate slightly. Nearly half of migrants are aged 15-29 years on arrival. The proportion with no more than primary education is higher than that of Mexico City natives, but the proportion with post-secondary education is similar. Pollution, lack of public safety, and other urban problems will probably combine to discourage migration to Mexico City in the future and encourage departures to less difficult cities.

  13. Shallow Faulting in Morelia, Mexico, Based on Seismic Tomography and Geodetically Detected Land Subsidence

    NASA Astrophysics Data System (ADS)

    Cabral-Cano, E.; Arciniega-Ceballos, A.; Vergara-Huerta, F.; Chaussard, E.; Wdowinski, S.; DeMets, C.; Salazar-Tlaczani, L.

    2013-12-01

    Subsidence has been a common occurrence in several cities in central Mexico for the past three decades. This process causes substantial damage to the urban infrastructure and housing in several cities and it is a major factor to be considered when planning urban development, land-use zoning and hazard mitigation strategies. Since the early 1980's the city of Morelia in Central Mexico has experienced subsidence associated with groundwater extraction in excess of natural recharge from rainfall. Previous works have focused on the detection and temporal evolution of the subsidence spatial distribution. The most recent InSAR analysis confirms the permanence of previously detected rapidly subsiding areas such as the Rio Grande Meander area and also defines 2 subsidence patches previously undetected in the newly developed suburban sectors west of Morelia at the Fraccionamiento Del Bosque along, south of Hwy. 15 and another patch located north of Morelia along Gabino Castañeda del Rio Ave. Because subsidence-induced, shallow faulting develops at high horizontal strain localization, newly developed a subsidence areas are particularly prone to faulting and fissuring. Shallow faulting increases groundwater vulnerability because it disrupts discharge hydraulic infrastructure and creates a direct path for transport of surface pollutants into the underlying aquifer. Other sectors in Morelia that have been experiencing subsidence for longer time have already developed well defined faults such as La Colina, Central Camionera, Torremolinos and La Paloma faults. Local construction codes in the vicinity of these faults define a very narrow swath along which housing construction is not allowed. In order to better characterize these fault systems and provide better criteria for future municipal construction codes we have surveyed the La Colina and Torremolinos fault systems in the western sector of Morelia using seismic tomographic techniques. Our results indicate that La Colina Fault

  14. Natural Hazards In Mexico City

    NASA Astrophysics Data System (ADS)

    Torres-Vera, M.

    2001-12-01

    Around the world more than 300 natural disasters occur each year, taking about 250,000 lives and directly affecting more than 200 million people. Natural hazards are complex and vary greatly in their frequency, speed of onset, duration and area affected. They are distinguished from extreme natural events, which are much more common and widespread, by their potential impacts on human societies. A natural disaster is the occurrence of a natural hazard on a large scale, involving great damage and, particularly in developing countries, great loss of life. The Basin of Mexico, whose central and southwestern parts are occupied by the urban area of Mexico City at the average altitude of 2,240 m above the sea level, is located on the southern edge of the Southern Plateau Central, on a segment of the Trans-Mexican Neovolcanic Belt that developed during Pliocene-Holocene times. The Basin of Mexico is a closed basin, which was created with the closing of the former Valley of Mexico because of basaltic-andesitic volcanism that formed the Sierra de Chichinautzin south of the city. The south-flowing drainage was obstructed and prompted the development of a lake that became gradually filled with sediments during the last 700,000 years. The lake fill accumulated unconformably over a terrain of severely dissected topography, which varies notably in thickness laterally. The major part of the urban area of Mexico City is built over these lake deposits, whereas the rest is built over alluvial material that forms the transition zone between the lake deposits and what constitutes the basement for the basin fill. In the present study, the effect of rain, fire and earthquakes onto Mexico City is evaluated. Rain risk was calculated using the most dangerous flood paths. The fire risk zones were determined by defining the vegetation areas with greater probability to catch fires. Earthquake hazards were determined by characterization of the zones that are vulnerable to damages produced by

  15. Volcanoe southeast of Mexico City

    NASA Image and Video Library

    2001-01-23

    ISS01-E-5316 (23 January 2001) -- Popocatépetl, or Popo, the active volcano located about 70 kilometers southeast of Mexico City, sends a plume south on January 23, 2001. The Expedition One crew onboard the International Space Station (ISS) observed and recorded this image with a digital still camera as it orbited to the northeast of the volcano. Popo has been frequently active for six years. On this day, the eruption plume reportedly rose to more than 9 kilometers above sea level (for reference, Popo's summit elevation is 5426 meters). Note the smaller ash plume below the main plume. The perspective from the ISS allowed the crew members this unique three dimensional view. Popo is situated between two large population centers: Mexico City (more than 18 million people, and just out of this image at right) and Puebla (about 1.2 million people), partially visible at lower left.

  16. Mexico City, Mexico as seen from STS-62

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This image is the clearest photo of Mexico City, Mexico taken from U.S. Manned Spacecraft. North is to the upper right. Mexico City sits in a basin surrounded by large volcanoes. The restricted atmospheric circulation in the basin, coupled with the inevitable air emissions produced by a city of 20 million people has created a critical air pollution problem for the city. In most photographs of the region, Mexico City is obscured by haze. The clarity of the photograph allows many key cultural features to be identified, including all of the major boulevards, the horse track (western part of the city), the university (south of the city), and the museum areas. Large, man-made ponds east of the city also stand out.

  17. Mexico City, Mexico as seen from STS-62

    NASA Image and Video Library

    1994-03-05

    STS062-84-028 (4-18 March 1994) --- According to NASA scientists this image is the clearest photo of Mexico City taken from United States manned spacecraft. North is to the upper right. Mexico City sits in a basin surrounded by large volcanoes. The restricted atmospheric circulation in the basin, coupled with the inevitable air emissions produced by a city of 20 million people has created a critical air pollution problem for the city. In most photographs of the region, Mexico City is obscured by haze. Scientists feel the clear atmosphere in this photograph may be due, in part, to the stringent air emission restrictions now in place. The clarity of the photograph allows many key cultural features to be identified, including all of the major boulevards, the horse track (western part of the city), the university (south of the city), and the museum areas. Large, man-made ponds east of the city also stand out.

  18. FUEL CELL BUS DEMONSTRATION IN MEXICO CITY

    EPA Science Inventory

    The report discusses the performance of a cull-size, zero-emission, Proton Exchange Membrane (PEM) fuel-cell-powered transit bus in the atmospheric environment of Mexico City. To address the air quality problems caused by vehicle emissions in Mexico City, a seminar on clean vehic...

  19. Land subsidence caused by groundwater exploitation in Suzhou City, China

    NASA Astrophysics Data System (ADS)

    Chen, Chongxi; Pei, Shunping; Jiao, Jiu Jimmy

    2002-09-01

    Suzhou City, located at the lower reaches of the Yangtze River in southeastern Jiangsu Province, is one of the few cities in China which suffer from severe ground settlement. A research project was carried out to investigate this problem. Geological and hydrogeological studies show that there is a multi-layered aquifer system with three distinct, soft mud layers of marine and lagoonal origins. An examination of historical records of groundwater extraction, water levels, and ground settlement shows that the ground subsidence is associated with the continuously increasing groundwater extraction in the deep, confined aquifer. It is believed that the consolidation of the soft mud layers, especially the third layer which is thick and close to the main pumped aquifer, contributes to the ground settlement. A three-dimensional finite difference numerical model representing the multi-layered aquifer system was developed to study the ground settlement in response to groundwater extraction. By calibrating the model with both the measured groundwater level and ground settlement, the aquifer parameters were estimated. The model outputs fit reasonably well with the observed results, which indicates that the numerical model can reproduce the dynamic processes of both groundwater flow and soil consolidation. The hydraulic conductivity of the third mud layer near the center of the ground settlement has been reduced by over 30% in the last 14 years. The gradual deterioration in the hydraulic conductivity of the mud may have significant adverse effect on the sustainable groundwater resource of the deep confined aquifer, since the recharge from the shallow aquifers through the mud layer is the only source of water to the deep aquifer. An analysis of the spatial distributions of groundwater drawdown and ground settlement shows that the area with maximum drawdown is not necessarily the area with maximum ground settlement due to the occurrence of the soft mud layer. A simple reallocation

  20. [Availability of condoms in Mexico City].

    PubMed

    Hernández-Girón, C; Cruz-Valdez, A; Quiterio-Trenado, M; Avila-Burgos, L; Peruga, A; Hernández-Avila, M

    2001-12-01

    At the beginning of 1999, Mexico occupied third place, after USA and Brazil, in the number of accumulated cases of AIDS (38,390 notified cases) in America. More than 80% of the cases corresponded to men between 20 and 44 years old. The transmission by sexual route has increased in both sexes, the proportion of men infected by sexual contact increased from 85% in 1991 to 90% in 1998 and in women this proportion increased from 41% in 1991 to 57% in 1998. The ratio male/female of cases of AIDS has varied from 17:1 in 1983 to 6:1 in 1998. Condom use is considered an effective method for the prevention of the transmission of STI's/HIV and therefore the availability is of paramount importance to promote use with the finality of combating these diseases. A simple randomized sampling was done in 612 establishments that included: drugstore, bars and nightclubs, hotels and motels, self-service shops and health centers in Mexico City, where am cross sectional study was performed during June and July of 1995, to evaluate the availability of condoms considering three important items: a) percent per capita required to buy an annual endowment of 100 condoms in comparison with this same indicator reported in other countries; b) physical availability, on behalf of the Secretaría de Salud, Mexico City, that considers the volume of existing condoms to be utilized for a year by the public sector in this city; c) physical availability of condoms in different evaluated locations. In order to purchase an annual supply of condoms an individual needs the assign $500 (Pesos) which represents 2.3 to 2.6% of the annual GNP per capita for 1998 and 1997 respectively. The physical availability of condoms, on behalf of the Secretaría de Salud, Mexico City, was 94.9% in health centers. In drugstores, hotels and motels, self-service shops, bars and nightclubs the availability of condoms was 100%, 82.9%, 75% and 1.2%, respectively. It has been documented that the adequate use of condom is an

  1. Subsidence monitoring with geotechnical instruments in the Mexicali Valley, Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Glowacka, E.; Sarychikhina, O.; Márquez Ramírez, V. H.; Robles, B.; Nava, F. A.; Farfán, F.; García Arthur, M. A.

    2015-11-01

    The Mexicali Valley (northwestern Mexico), situated in the southern part of the San Andreas fault system, is an area with high tectonic deformation, recent volcanism, and active seismicity. Since 1973, fluid extraction, from the 1500-3000 m depth range, at the Cerro Prieto Geothermal Field (CPGF), has influenced deformation in the Mexicali Valley area, accelerating the subsidence and causing slip along the traces of tectonic faults that limit the subsidence area. Detailed field mapping done since 1989 (González et al., 1998; Glowacka et al., 2005; Suárez-Vidal et al., 2008) in the vicinity of the CPGF shows that many subsidence induced fractures, fissures, collapse features, small grabens, and fresh scarps are related to the known tectonic faults. Subsidence and fault rupture are causing damage to infrastructure, such as roads, railroad tracks, irrigation channels, and agricultural fields. Since 1996, geotechnical instruments installed by CICESE (Centro de Investigación Ciéntifica y de Educación Superior de Ensenada, B.C.) have operated in the Mexicali Valley, for continuous recording of deformation phenomena. Instruments are installed over or very close to the affected faults. To date, the network includes four crackmeters and eight tiltmeters; all instruments have sampling intervals in the 1 to 20 min range. Instrumental records typically show continuous creep, episodic slip events related mainly to the subsidence process, and coseismic slip discontinuities (Glowacka et al., 1999, 2005, 2010; Sarychikhina et al., 2015). The area has also been monitored by levelling surveys every few years and, since the 1990's by studies based on DInSAR data (Carnec and Fabriol, 1999; Hansen, 2001; Sarychikhina et al., 2011). In this work we use data from levelling, DInSAR, and geotechnical instruments records to compare the subsidence caused by anthropogenic activity and/or seismicity with slip recorded by geotechnical instruments, in an attempt to obtain more information

  2. Geology of the region of Guadalajara, Mexico, and its relationships with processes of subsidence

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Delgado-Argote, L. A.; Nuñez-Cornu, F. J.; Sanchez, J. J.

    2008-12-01

    The city of Guadalajara, Mexico, began an accelerated urban growth in early 1950. During a span of 25 years a large number of gullies were artificially filled, with the aim of incorporating new areas for urbanization, particularly in the areas north and west of the city. These gullies originally formed a complex dendritic-type system, whose evolution may be associated with faults or fracture zones whose current identification are only possible based on escarpments along the Canyon of the Rio Grande de Santiago (CRGS), north of Guadalajara. Reports of affectations documented in the 80's described subsidence in buildings and infrastructure, a process that has been continued during 2008. We present the results of work done in the CRGS, which is a tectonic erosive-depression with an average depth of 500 m and exhibits a sequence of volcanic and sedimentary deposits with rapid lateral facies changes. The stratigraphic column spans a 15 km-long section along the Matatlán-Arcediano road, and, from top to bottom contains: 1) Unconsolidated pumice and tuffs with an average thickness of 12 m; 2) basaltic lavas with average thickness of 60 m; 3) the San Gaspar ignimbrite; 4) fluvial- sedimentary deposits with a thickness of approximately 20 meters that include both sub-rounded and angular volcanic clasts, with sizes up to 0.15 m; 5) a thick sequence of ignimbrites and dacitic lavas. At a depth of 1200 m.a.s.l. in the town of Arcediano, the basal sequence is composed of dacites and andesites with interbedded pumice-rich ignimbrites with 10-20 m thickness. The Rio Grande de Santiago talweg to 1018 m.a.s.l. (apparently the base of the sequence) is formed by andesite lava. In the area of San Gaspar we identified oblique-normal left-lateral faults in lavas, with a strike 191° and a dip 89°. In the Colimilla dam, 1297 m.a.s.l., we observed normal faulting (strike 267° and dip 81°), with 20-30 m jumps with reference to a unit of tephra of 3-10 m thickness. The lavas in this

  3. Subsidence Modeling of the Over-exploited Granular Aquifer System in Aguascalientes, Mexico

    NASA Astrophysics Data System (ADS)

    Solano Rojas, D. E.; Wdowinski, S.; Minderhoud, P. P. S.; Pacheco, J.; Cabral, E.

    2016-12-01

    The valley of Aguascalientes in central Mexico experiences subsidence rates of up to 100 [mm/yr] due to overexploitation of its aquifer system, as revealed from satellite-based geodetic observations. The spatial pattern of the subsidence over the valley is inhomogeneous and affected by shallow faulting. The understanding of the subsoil mechanics is still limited. A better understanding of the subsidence process in Aguascalientes is needed to provide insights for future subsidence in the valley. We present here a displacement-constrained finite-element subsidence model using Deltares iMOD (interactive MODeling), based on the USGS MODFLOW software. The construction of our model relies on 3 main inputs: (1) groundwater level time series obtained from extraction wells' hydrographs, (2) subsurface lithostratigraphy interpreted from well drilling logs, and (3) hydrogeological parameters obtained from field pumping tests. The groundwater level measurements were converted to pore pressure in our model's layers, and used in Terzaghi's equation for calculating effective stress. We then used the effective stresse along with the displacement obtained from geodetic observations to constrain and optimize five geo-mechanical parameters: compression ratio, reloading ratio, secondary compression index, over consolidation ratio, and consolidation coefficient. Finally, we use the NEN-Bjerrum linear stress model formulation for settlements to determine elastic and visco-plastic strain, accounting for the aquifer system units' aging effect. Preliminary results show higher compaction response in clay-saturated intervals (i.e. aquitards) of the aquifer system, as reflected in the spatial pattern of the surface deformation. The forecasted subsidence for our proposed scenarios show a much more pronounced deformation when we consider higher groundwater extraction regimes.

  4. Subsidence Modeling of the Over-exploited Granular Aquifer System in Aguascalientes, Mexico

    NASA Astrophysics Data System (ADS)

    Solano Rojas, D. E.; Pacheco, J.; Wdowinski, S.; Minderhoud, P. S. J.; Cabral-Cano, E.; Albino, F.

    2017-12-01

    The valley of Aguascalientes in central Mexico experiences subsidence rates of up to 100 [mm/yr] due to overexploitation of its aquifer system, as revealed from satellite-based geodetic observations. The spatial pattern of the subsidence over the valley is inhomogeneous and affected by shallow faulting. The understanding of the subsoil mechanics is still limited. A better understanding of the subsidence process in Aguascalientes is needed to provide insights for future subsidence in the valley. We present here a displacement-constrained finite-element subsidence model, based on the USGS MODFLOW software. The construction of our model relies on 3 main inputs: (1) groundwater level time series obtained from extraction wells' hydrographs, (2) subsurface lithostratigraphy interpreted from well drilling logs, and (3) hydrogeological parameters obtained from field pumping tests. The groundwater level measurements were converted to pore pressure in our model's layers, and used in Terzaghi's equation for calculating effective stress. We then used the effective stress along with the displacement obtained from geodetic observations to constrain and optimize five geo-mechanical parameters: compression ratio, reloading ratio, secondary compression index, over consolidation ratio, and consolidation coefficient. Finally, we use the NEN-Bjerrum linear stress model formulation for settlements to determine elastic and visco-plastic strain, accounting for the aquifer system units' aging effect. Preliminary results show higher compaction response in clay-saturated intervals (i.e. aquitards) of the aquifer system, as reflected in the spatial pattern of the surface deformation. The forecasted subsidence for our proposed scenarios show a much more pronounced deformation when we consider higher groundwater extraction regimes.

  5. Determination of Soft Lithology Causes The Land Subsidence in Coastal Semarang City by Resistivity Methods

    NASA Astrophysics Data System (ADS)

    Widada, Sugeng; Saputra, Sidhi; Hariadi

    2018-02-01

    Semarang City is located in the northern coastal plain of Java which is geologically composed of alluvial deposits. The process of the sediment diagenesis has caused a land subsidence. On the other hand, the development of the industrial, service, education and housing sectors has increased the number of building significantly. The number of building makes the pressure of land surface increased, and finally, this also increased the rate of land subsidence. The drilling data indicates that not all layers of lithology are soft layers supporting the land subsidence. However, vertical distribution of the soft layer is still unclear. This study used Resistivity method to map out the soft zone layers of lithology. Schlumberger electrode configuration with sounding system method was selected to find a good vertical resolution and maximum depth. The results showed that the lithology layer with resistivity less than 3 ohm is a layer of clay and sandy clay that has the low bearing capacity so easily compressed by pressure load. A high land subsidence is happening in the thick soft layer. The thickness of that layer is smaller toward the direction of avoiding the beach. The improvement of the bearing capacity of this layer is expected to be a solution to the problem of land subsidence.

  6. Land Subsidence Monitoring by InSAR Time Series Technique Derived From ALOS-2 PALSAR-2 over Surabaya City, Indonesia

    NASA Astrophysics Data System (ADS)

    Aditiya, A.; Takeuchi, W.; Aoki, Y.

    2017-12-01

    Surabaya is the second largest city in Indonesia and the capital of East Java Province with rapid population and industrialization. The impact of urbanization in the big city can suffer potential disasters either nature or anthropogenic such as land subsidence and flood. The pattern of land subsidence need to be mapped for the purposes of planning and structuring the city as well as taking appropriate policy in anticipating and mitigating the impact. This research has used interferometric Synthetic Aperture Radar (InSAR) Small Baseline Subset (SBAS) technique and applied time series analysis to investigate land subsidence occured. The technique includes the process of focusing the SAR data, incorporating the precise orbit, generating interferogram and phase unwrapping using SNAPHU algorithms. The results showed land subsidence has been detected during 2014-2017 over Surabaya city area using ALOS-2/PALSAR-2 images data. These results reveal the subsidence has observed in several area in Surabaya in particular northern part reach up to ∼2 cm/year. The fastest subsidence occurs in highly populated areas suffer vulnerable to flooding and sea level rise impact. In urban areas we found a correlation between land subsidence with residential or industrial land use. It concludes that land subsidence is mainly caused by ground water consumption for industrial and residential use respectively.

  7. 76 FR 73595 - Healthcare Technology, Policy & Trade Mission: Mexico City, Mexico, May 13-16, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-29

    ... printed company directory; Networking reception at Ambassador's residence or other venue in Mexico City on... Mission: Mexico City, Mexico, May 13-16, 2012 AGENCY: International Trade Administration, Department of... policy and trade mission to Mexico City, May 13-16, 2012. This mission is intended to focus on a variety...

  8. Scientists Focus on Land Subsidence Impacts on Coastal and Delta Cities

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2014-05-01

    Some coastal and delta cities around the world are sinking but not necessarily due only to sea level rise and impacts from extreme weather events. Land subsidence that is caused by anthropogenic processes—including the extraction of groundwater, oil, and gas and the drainage of soils—is a significant concern for Jakarta, Indonesia; Manila, Philippines; New Orleans, La.; and many other coastal and delta cities, according to scientists at a 28 April briefing held at the European Geosciences Union's General Assembly in Vienna, Austria.

  9. [Typhus in Mexico City in 1915].

    PubMed

    Rodríguez, Martha Eugenia

    2016-01-01

    The year 1915 was particularly difficult; it was characterized by droughts, famines, and outbreaks of diseases including typhus.This text exposes its spread in Mexico City as well as the measures implemented to combat it, carried out before knowing the etiology of the illness, focused on cleaning up the environment and the measures undertaken afterwards with the aim of delousing people.

  10. Libraries in the Mexico City Earthquake.

    ERIC Educational Resources Information Center

    de Zamora, Rosa Maria Fernandez

    1990-01-01

    As a result of damage from the Mexico City earthquake of September 1985, some of the busiest public and special libraries had to be closed. A National Committee for the Reconstruction of Libraries was established, and international support was received through the International Federation of Library Associations and Institutions and other…

  11. Emissions from forest fires near Mexico City.

    Treesearch

    R.J. Yokelson; S.P. Urbanski; E.L. Atlas; D.E. Toohey; E.C. Alvarado; J.D. Crounse; P.O. Wennberg; M.E. Fisher; C.E. Would; T.L. Campos; K. Adachi; P.T. Buseck; W.M. Hao

    2007-01-01

    The emissions of NOx (defined as NO (nitric oxide) + NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of fuel burned from fires in the pine forests that dominate the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The ammonia (NH3...

  12. Mesozoic to Recent, regional tectonic controls on subsidence patterns in the Gulf of Mexico basin

    NASA Astrophysics Data System (ADS)

    Almatrood, M.; Mann, P.; Bugti, M. N.

    2016-12-01

    We have produced subsidence plots for 26 deep wells into the deeper-water areas of the Gulf of Mexico (GOM) in order to identify regional tectonic controls and propose tectonic phases. Our results show three sub-regions of the GOM basin that have distinctive and correlative subsidence patterns: 1) Northern GOM from offshore Texas to central Florida (9 wells) - this area is characterized by a deeply buried, Triassic-early Jurassic rift event that is not represented by our wells that penetrate only the post-rift Cretaceous to recent passive margin phase. The sole complexity in the passive margin phase of this sub-region is the acceleration of prograding clastic margins including the Mississippi fan in Miocene time; 2) Southeastern GOM in the Straits of Florida and Cuba area (5 wells) - this area shows that the Cretaceous passive margin overlying the rift phase is abruptly drowned in late Cretaceous as this part of the passive margin of North America that is flexed and partially subducted beneath the Caribbean arc as it encroaches from the southwest to eventually collide with the North American passive margin in the Paleogene; 3) Western GOM along the length of the eastern continental margin of Mexico (12 wells) - this is the most complex of the three areas in that shares the Mesozic rifting and passive margin phase but is unique with a slightly younger collisional event and foreland basin phase associated with the Laramide orogeny in Mexico extending from the KT boundary to the Oligocene. Following this orogenic event there is a re-emergence of the passive margin phase during the Neogene along locally affected by extensional and convergent deformation associated with passive margin fold belts. In summary, the GOM basin exhibits evidence for widespread rifting and passive margin formation associated with the breakup of Pangea in Mesozoic times that was locally superimposed and deformed during the late Cretaceous-Paleogene period by: 1) Caribbean subduction and

  13. A Hazy Day in Mexico City

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Mexico City has one of the world's most serious air pollution problems. The city is located atop a high plain at an altitude of 2200 meters, and is surrounded on three sides by mountains and snow-capped volcanoes. Since incident solar radiation does not vary significantly with season at tropical latitudes, photochemical smog is produced much of the year. In winter, air quality can worsen significantly when thermal inversions keep polluted air masses close to the surface.

    Atmospheric particulates (aerosols) are readily visible at oblique view angles, and differences in aerosol amount on two days are indicated by these images of central Mexico from the Multi-angle Imaging SpectroRadiometer (MISR). The images at left and center are natural color views acquired by MISR's 70-degree forward-viewing camera on April 9 and December 5, 2001, respectively. Mexico City can be identified in the center panel by the large area of haze accumulation above image center. Two small brighter patches within the hazy area indicate low fog. In the left-hand panel, the city basin appears significantly clearer, but some haze remains apparent across the Sierra Madre mountains in the lower portion of the images. On the right is an elevation field corresponding to the December 5 view. Automated MISR stereoscopic retrievals reveal the clouds at lower right to be at very high altitudes, in contrast to the low-lying haze and fog near Mexico City. When the stereo retrieval determines that a location is not covered by clouds, digital terrain elevation data are displayed instead. High clouds appear as the orange and red areas, and mountainous areas appear light blue and green. The position of the clouds within the 70-degree image are slightly southward of their location in the elevation map as a consequence of geometric parallax.

    Major sources of air pollutants within the basin enclosing the Mexico City urban area include exhaust from 3.5 million vehicles, thousands of industries, and

  14. Fluoride content in table salt distributed in Mexico City, Mexico.

    PubMed

    Hernández-Guerrero, Juan Carlos; de la Fuente-Hernández, Javier; Jiménez-Farfán, Maria Dolores; Ledesma-Montes, Constantino; Castañeda-Castaneira, Enrique; Molina-Frechero, Nelly; Jacinto-Alemán, Luís Fernando; Juárez-Lopez, Lilia Adriana; Moreno-Altamirano, Alejandra

    2008-01-01

    The aim of this study was to analyze table salt available in Mexico City's market to identify the fluoride concentrations and to compare these with the Mexican regulations. We analyzed 44 different brands of table salt. All samples were purchased at random in different stores, supermarkets, and groceries from Mexico City's metropolitan area and analyzed in triplicate in three different laboratories (nine determinations per sample) with an Orion 720 A potentiometer and an Orion 9609 BN ion-specific electrode. Fluoride concentration in the samples varied from 0 ppm to 485 ppm. It was found that fluoride concentration varied widely among the analyzed brands. Also, we found that fluoride concentration in 92 percent of the analyzed samples did not match with that printed on the label. Only 6.8 percent of the analyzed samples contained fluoride concentrations that meet Mexican and WHO regulations. The broad variation in the analyzed samples suggests that Mexican Public Health authorities must implement more stringent regulation guidelines and procedures for controlling the distribution of salt and its fluoride concentration for human consumption.

  15. [Demography of Mexico City. The same problems with less population].

    PubMed

    Camposortega Cruz, S

    1991-01-01

    The Mexico City metropolitan area currently extends over 4451.2 sq km, completely covering the Federal District and 27 municipios in the state of Mexico. The current population of the Mexico City metropolitan area is estimated at about 16.1 million and its growth rate at approximately 2%/year. The crude birth rate is 24/1000 and the crude death rate 6/1000. The metropolitan Mexico City population represents 18.6% of the total Mexican population. Mexico's other large cities fall far behind in total population, Guadalajara with 3.16 million, Monterrey with 2.77 million, and Puebla with 1.5 million. Mexico City is 1 of the 5 largest cities of the world. Estimates of the current Mexico City population differ substantially from projections completed in the 1980s, which calculated populations of 19-22 million. The explanation of the difference lies primarily in overestimation of the metropolitan population in the 1980 census, the basis for the projections. Preliminary data from the 1990 census, data from the 1987 National Fertility and Health Survey, vital statistics, and some data on internal migration allow a preliminary correction of calculations relating to Mexico's population dynamics. During the 20th century, Mexico City's population has grown from 345,000 in 1900 to 1,029,000 in 1930, 3,136,000 in 1950, 9,045,000 in 1970, and 15,785,000 in 1990. The most rapid growth occurred in 1930-70, when the population grew by more than 5% annually. The growth rate declined to 3.65% between 1970-80 and according to preliminary estimated to 1.92% in 1980-90. Factors explaining the declining growth rate may include the fertility decline in Mexico City, reorientation of migration away from Mexico City and toward inntermediate cities with under 1 million inhabitants, and departures from Mexico City caused by the 1985 earthquakes, private and public decentralization policies, pollution, and other factos which have reduced the attractiveness of the capital. The reevised

  16. Ozone's Threat Hits Back Mexico City

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Retama, A.; Guzman, D.

    2016-12-01

    Last March the Mexican authorities activated after 13 years the environmental alarm when ozone (O3) reached 210 ppb. The emergency measures created confusion among the public, who had lost memory of previous air quality crisis. Despite Mexico City has experienced a significant progress towards achieving cleaner air during the last 20 years, a recent relaxation in traffic regulations and meteorology favorable for photochemical activity triggered this new episode. All criteria pollutants of primary origin have been controlled and are in compliance with the Mexican Air Quality Standards. However, O3 and fine particles still exceed the standard threshold concentrations. For instance, 49-64% of the days have exceeded the 1-hour O3 standard of 95 ppb during the last 5 years. The current control policies, which responded to the integration of air quality information by authorities and scientists, have apparently started to lose effectiveness. Although precursor gases, such as alkanes and aromatics have shown an important decrease, reactive olefins have gained importance. The increase of motor-vehicles in recent years seems to fuel again the atmosphere's reactivity. This paper analyses the effectiveness of the emergency measures during the crisis based on the knowledge obtained from previous large field studies and the comprehensive data collected by the local air quality monitoring network. It is 10 years from MILAGRO, the last interdisciplinary study that examined the air pollution of the most populous city in North America. We call for a new collaborative research initiative based on a major field measurement campaign with the target of revealing new insights into the meteorology, emission of primary pollutants and precursor gases, photochemical production and formation of secondary particles in the atmosphere of Mexico City to improve its air quality, as well as of similar cities in the developing world.

  17. Seismic Hazard Management in Mexico City

    NASA Astrophysics Data System (ADS)

    Wintergerst, L.

    2007-05-01

    Mexico City is one of the largest cities in the world. More than 8.5 million residents and 4.5 million floating population are in the city itself, but with the surrounding suburbs the number of people that could be affected by natural and man-made hazards rises to approximately 20 million. The main risk to the city as a whole is a large magnitude earthquake. Since there is reason to prepare for a credible seismic scenario of Mw = 8.2, which would exceed the damages caused during the 1985 earthquake (Mw = 8.1), we founded the Metropolitan Geologic Service (MGS) in 1998. The MGS has developed geologic and seismic hazard maps for the city (http:www.proteccioncivil.df.gob.mx). The maps include three separate risk maps for low height (3 stories), medium height (10 stories) and tall buildings (10 stories). The maps were prepared by using the maximum horizontal accelerations documented during the 1985 earthquake, and wave propagation modeling for buildings of different resonant periods (T = 0.0, 1.0 and 2.0 sec). In all cases, the risk zones were adjusted to include documented damage during the 1957, 1979 and 1985 earthquakes. All three maps show a high risk zone in the north-central portion of the city, elongated in a N-S direction, which corresponds with a narrow graben where the thickness of alluvial sediments is particularly large, and where wave amplification is accentuated. Preparation of these maps, and others used for planning, has been facilitated by the ongoing elaboration of a Dynamic Geographical Information System, which is based on geo-scientific information, includes all types of risks, and incorporates vulnerability models. From the risk management standpoint, we have elaborated the Permanent Contingency Plan for Mexico City, which in its Earthquakes chapter includes plans for coordination and for organizing attention to the population in the event of a seismic disaster. This Permanent Plan follows the philosophy of Descartes' Method, has 11 processes (6

  18. Influence of solid waste and topography on urban floods: The case of Mexico City.

    PubMed

    Zambrano, Luis; Pacheco-Muñoz, Rodrigo; Fernández, Tania

    2018-02-24

    Floods in cities are increasingly common as a consequence of multifactor watershed dynamics, including geomorphology, land-use changes and land subsidence. However, urban managers have focused on infrastructure to address floods by reducing blocked sewage infrastructure, without significant success. Using Mexico City as a case study, we generated a spatial flood risk model with geomorphology and anthropogenic variables. The results helped contrast the implications of different public policies in land use and waste disposal, and correlating them with flood hazards. Waste disposal was only related to small floods. 58% of the city has a high risk of experiencing small floods, and 24% of the city has a risk for large floods. Half of the population with the lowest income is located in the high-risk areas for large floods. These models are easy to build, generate fast results and are able to help to flood policies, by understanding flood interactions in urban areas within the watershed.

  19. Designing Freshwater Resilience for the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Freeman, S.; Wi, S.; Brown, C.

    2017-12-01

    There are few places in the world where the water management challenges associated with global urbanization are as fully visible as in the Greater Mexico City Metropolitan Area (MCMA). MCMA has a population of 22 million of which only 82% have daily water provision and this figure is projected by local agencies to decrease drastically in the next decade due to population growth, infrastructure degradation and climate change. The city is served by a massive water delivery system, consisting of complex network of infrastructure in the surrounding basins that provides about 40% of the supply for MCMA and is characterized by increasing land use change and competition for water. The remaining 60% of MCMA's water is sourced internally from already depleted groundwater resources whose exploitation also results in significant subsidence throughout the city, further damaging already degraded infrastructure. Consequently, there is interest and need for investments that improve the performance of the freshwater delivery system, including local resources and connected basins, in the face of change and shocks that can be only partially anticipated. The quest for such resilience is a common theme in urban infrastructure design yet practical approaches for achieving it remain nascent. In this study, we use MCMA and the Cutzamala Water supply system to demonstrate a quantitative framework to evaluate investment strategies which seek resilience for the water supply system of MCMA. Multiobjective optimization and decisions under deep uncertainty approaches are used to evaluate the best performing investment portfolios across different resilience performance metrics which encompass social equity, environmental and economic objectives. This analysis shows dynamic system responses that result from different investment portfolios, elucidating difficult planning and management decisions around tradeoffs between allocations as well as performance metrics (e.g short period of total failure

  20. Urbanisation and flood vulnerability in the peri-urban interface of Mexico City.

    PubMed

    Aragón-Durand, Fernando

    2007-12-01

    Chronic flooding in the Chalco valley, state of Mexico, Mexico, is the outcome of past and present socio-environmental changes which have taken place in Mexico City's south-eastern peri-urban interface. This flooding is the result of a complex interaction between urbanisation in an ex-lacustrine area, permanent ecological deterioration and ground subsidence, poor sanitation and inadequate policy responses. Far from solving the flooding problem, short-term policy responses have created increasingly unsafe conditions for current residents. A socio-historical analysis of disasters reveals the importance of taking into consideration particular social actors and institutions in hazard generation and flood vulnerability over time. This paper analyses three aspects of this flooding: first, the importance of approaching floods from a socio-historical perspective; second, the relation between urbanisation, former policies and flood risk generation; and third, current policy responses to and the failure in the risk management of La Compañía Canal.

  1. [The cholera epidemic of 1833 and mortality in Mexico City].

    PubMed

    Velasco, M D

    1992-01-01

    The author examines the impact of the 1833 cholera epidemic in Mexico City, Mexico, on social, economic, and political aspects of life in that city. She finds that some five percent of the population died during the epidemic, and enumerates them by age and sex.

  2. Latin America's supercity--the metropolitan area of Mexico City.

    PubMed

    1987-02-01

    Big and still growing, Mexico City and its environs is soon to be the world's largest metropolitan area. The lure of city amenties--jobs, health care, schooling, and cheap food--and the hope of a better life bring 1000 rural migrants to Mexico City every day. Between 1950 and 1980, Mexico City grew at an annual average rate of 5.4%. Mexico City is typical of Latin American supercities, holding an impressive portion of the nation's population and commanding the lion's share of the country's economic activities. It is primarily due to the rapid growth in the northern periphery of the municipalities that Mexico City is expected to grow into the world's largest metropolitan area by the year 2000. Given the high proportion of youth relative to the total population, it is not suprising that average household sizes in Mexico City are large. About 60% to 70% of all families have no access to the formal housing market; much of the urban expansion has occurred through the emergence of squatter communities. Water may indeed be the most serious of all of Mexico City's infrastructural problems. Other problems include: 1) the government cannot meet the demands for educational buildings and personnel; 2) in 1982, 10.3% of the metropolitan population lived in extreme poverty and an additional 22.6% were unable to satisfy their basic needs; and 3) transport is a central problem. Demographic sources for Mexico are discussed.

  3. Ground subsidence and associated ground fracturing in urban areas: InSAR monitoring of active tectonic structures (Ciudad Guzman, Colima Graben - Mexico)

    NASA Astrophysics Data System (ADS)

    Bignami, C.; Brunori, C.; Zucca, F.; Groppelli, G.; Norini, G.; Hernandez, N. D.; Stramondo, S.

    2013-12-01

    This study focuses on the observation of a creeping phenomenon that produces subsidence of the Zapotlan basin and ground fracturing in correspondence of the Ciudad Guzmàn (Jalisco - Mexico). The September 21, 2012, the Ciudad Guzmàn has been struck by a phenomenon of ground fracturing of about 1.5 km of length. This event caused the deformation of the roads and the damage of 30 houses, of which eight have been declared uninhabitable. The alignment of fractures is coincident with the escarpments produced in September 19, 1985, in the Ciudad Guzman urban area, when a strong earthquake, magnitude 8.1, struck the Mexican area, causing the deaths of at least 10,000 people and serious damage in Mexico City. In Ciudad Guzmán, about 60% of the buildings were destroyed, with about 50 loss of life. The city is located in the Zapotlan basin (northern Colima graben), a wide tectonic depression where the depth of the infilling sediments is about 1 km. This subsidence cannot be measured outside the urbanized area, but it can be considered as a deformation mechanism of the central part of the basin. In order to detect and mapping the spatio-temporal features of the processes that led to this event, we applied InSAR multi-temporal techniques to analyze a dataset of ENVISAT satellite SAR images, acquired in a time span between 2003-2010. InSAR techniques detect a subsidence of the north-western part of Ciudad Guzmàn of about 15 mm/yr in the time interval 2003-2010. The displacement occurred in September 21, 2012, was detected using two RadarSAT2 acquisitions (2012-03-22 and 2013-03-17). The explanation of surface movements based on interferometric results, ground data and geological field observations, allowed confirming surface effect due to the overexploitation of the aquifers and highlights a subsidence due to anthropogenic causes coupled to buried tectonic structures.

  4. Albuquerque, New Mexico, USA: A sunbelt city rapidly outgrowing its aquifer

    SciTech Connect

    Turin, H.J.; Gaume, A.N.; Bitner, M.J.

    1997-02-01

    Albuquerque, New Mexico, is located along the Rio Grande in central New Mexico, at an elevation of 5280 feet. Albuquerque`s climate reflects its high desert setting; average annual precipitation in the basin is only 8 to 10 inches. The Albuquerque metropolitan area is part of the rapidly growing {open_quotes}sunbelt{close_quotes} region of the southwestern United States and is undergoing rapid development. The municipal, industrial, and residential water needs of the entire population are currently met by groundwater, while agricultural needs within the basin are met by surface water diverted from the Rio Grande. While the city is blessed with an extremelymore » productive aquifer, current metropolitan area annual groundwater extractions of 170,000 acre-feet far exceed the sustainable yield of the aquifer. Continued drawdown will lead to greater pumping costs, ground surface subsidence problems, and eventual aquifer depletion. At the same time, industrial and non-point-source contamination and naturally occurring arsenic levels are raising concerns about groundwater quality. New Mexico water law has required the City to acquire surface water rights and allocations on the Rio Grande sufficient to offset estimated losses from the river induced by the City`s groundwater extraction. It has become increasingly clear that the induced recharge had been greatly overestimated, and that the City is thus not actually consuming its surface water as intended. The City, in cooperation with local, state, and federal agencies, has explored a variety of conjunctive use proposals, all designed to permit the City to use its surface water more directly. The City Council is presently considering a strategy calling for full use of the city`s surface water resources and creation of a groundwater drought reserve. Implementation of this strategy will require regulatory approval and major capital investment, both of which require political support.« less

  5. Strong advocacy led to successful implementation of smokefree Mexico City.

    PubMed

    Crosbie, Eric; Sebrié, Ernesto M; Glantz, Stanton A

    2011-01-01

    To describe the approval process and implementation of the 100% smokefree law in Mexico City and a competing federal law between 2007 and 2010. Reviewed smokefree legislation, published newspaper articles and interviewed key informants. Strong efforts by tobacco control advocacy groups and key policymakers in Mexico City in 2008 prompted the approval of a 100% smokefree law following the WHO FCTC. As elsewhere, the tobacco industry utilised the hospitality sector to block smokefree legislation, challenged the City law before the Supreme Court and promoted the passage of a federal law that required designated smoking areas. These tactics disrupted implementation of the City law by causing confusion over which law applied in Mexico City. Despite interference, the City law increased public support for 100% smokefree policies and decreased the social acceptability of smoking. In September 2009, the Supreme Court ruled in favour of the City law, giving it the authority to go beyond the federal law to protect the fundamental right of health for all citizens. Early education and enforcement efforts by tobacco control advocates promoted the City law in 2008 but advocates should still anticipate continuing opposition from the tobacco industry, which will require continued pressure on the government. Advocates should utilise the Supreme Court's ruling to promote 100% smokefree policies outside Mexico City. Strong advocacy for the City law could be used as a model of success throughout Mexico and other Latin American countries.

  6. Strong advocacy led to successful implementation of smokefree Mexico City

    PubMed Central

    Crosbie, Eric; Sebrié, Ernesto M; Glantz, Stanton A

    2011-01-01

    Objective To describe the approval process and implementation of the 100% smokefree law in Mexico City and a competing federal law between 2007 and 2010. Methods Reviewed smokefree legislation, published newspaper articles and interviewed key informants. Results Strong efforts by tobacco control advocacy groups and key policymakers in Mexico City in 2008 prompted the approval of a 100% smokefree law following the WHO FCTC. As elsewhere, the tobacco industry utilised the hospitality sector to block smokefree legislation, challenged the City law before the Supreme Court and promoted the passage of a federal law that required designated smoking areas. These tactics disrupted implementation of the City law by causing confusion over which law applied in Mexico City. Despite interference, the City law increased public support for 100% smokefree policies and decreased the social acceptability of smoking. In September 2009, the Supreme Court ruled in favour of the City law, giving it the authority to go beyond the federal law to protect the fundamental right of health for all citizens. Conclusions Early education and enforcement efforts by tobacco control advocates promoted the City law in 2008 but advocates should still anticipate continuing opposition from the tobacco industry, which will require continued pressure on the government. Advocates should utilise the Supreme Court’s ruling to promote 100% smokefree policies outside Mexico City. Strong advocacy for the City law could be used as a model of success throughout Mexico and other Latin American countries. PMID:21059606

  7. HYDROCARBON AND CARBONYL OZONE PRECURSORS IN MEXICO CITY AMBIENT AIR

    EPA Science Inventory

    Urban air pollution is an environmental problem in many cities around the world that has serious immediate and long-term implications to the health of the population and to the physical environment. Mexico City, in particular, faces a severe air pollution problem. The city is...

  8. Establishing a Water Resources Resilience Baseline for Mexico City

    NASA Astrophysics Data System (ADS)

    Behzadi, F.; Ray, P. A.

    2017-12-01

    There is a growing concern for the vulnerability of the Mexico City water system to shocks, and the capacity of the system to accommodate climate and demographic change. This study presents a coarse-resolution, lumped model of the water system of Mexico City as a whole, designed to identify system-wide imbalances, and opportunities for large-scale improvements in city-wide resilience through investments in water imports, exports, and storage. In order to investigate the impact of climate change in Mexico City, the annual and monthly trends of precipitation and temperature at 46 stations near or inside the Mexico City were analyzed. The statistical significance of the trends in rainfall and temperature, both over the entire period of record, and the more recent "climate-change-impacted period" (1970-2015), were determined using the non-parametric Mann-Kendall test. Results show a statistically significant increasing trend in the annual mean precipitation, mean temperature, and annual maximum daily temperature. However, minimum daily temperature does not appear to be increasing, and might be decreasing. Water management in Mexico City faces particular challenges, where the winter dry season is warming more quickly than the wet summer season. A stress test of Mexico City water system is conducted to identify vulnerabilities to changes in exogenous factors (esp., climate, demographics, land use). Following on the stress test, the relative merits of adaptation options that might improve the system's resilience and sustainability will be assessed.

  9. [Cholera in Mexico City during the nineteenth century].

    PubMed

    Marquez Morfin, L

    1992-01-01

    The author draws on epidemiological and historical records for this description of the demographic impact of the fatal cholera epidemics of 1833 and 1848-1850 on the population of Mexico City, Mexico. Consideration is given to political, economic, and social factors that influenced the spread of the disease.

  10. Strong Ground Motions Scenarios for Mexico City

    NASA Astrophysics Data System (ADS)

    Cabrera, E.; Chavez, M.; Madariaga, R.; Mai, P. M.; Frisenda, M.; Perea, N.

    2005-12-01

    The recordings available in Mexico City (MC) for extreme magnitude Subduction Superficial (SS), Subduction Deep (SD), and Crustal Superficial (CS) events are about 30 accelerograms (obtained at 10 sites) for the SS 19 09 1985 earthquake (Ms 8.1, Mw 8.01). In this work we generated broadband synthetic accelerograms expected in MC stiff (S) and compressive soils (C),for SS (Mw 8.5, 8.7), SD (Mw 7.6) and CS (Mw 7.5) earthquakes.The frequencies lower than 0.5 Hz were simulated by using a 4th order FD method, including a (fractal) finite-fault description of the sources. The frequencies larger than 0.5 Hz were modeled by the empirical Green function technique. We propose upper bounds of 0.4g and 2g (g=9.8m/s2)for the maximum response spectra acceleration(5 percent damping) expected in the S and C soils of MC, respectively.

  11. First report of Stegomyia aegypti (= Aedes aegypti) in Mexico City, Mexico.

    PubMed

    Kuri-Morales, P; Correa-Morales, F; González-Acosta, C; Sánchez-Tejeda, G; Dávalos-Becerril, E; Fernanda Juárez-Franco, M; Díaz-Quiñonez, A; Huerta-Jimenéz, H; Mejía-Guevara, M D; Moreno-García, M; González-Roldán, J F

    2017-06-01

    Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is a species of mosquito that is currently widespread in Mexico. Historically, the mosquito has been distributed across most tropical and subtropical areas lower than 1700 m a.s.l. Currently, populations that are found at higher altitudes in regions with cold and dry climates suggest that these conditions do not limit the colonization and population growth of S. aegypti. During a survey of mosquitoes in September 2015, larvae of S. aegypti mosquitoes were found in two different localities in Mexico City, which is located at about 2250 m a.s.l. Mexico City is the most populous city in Mexico and has inefficient drainage and water supply systems. These factors may result in the provision of numerous larval breeding sites. Mosquito monitoring and surveillance are now priorities for the city. © 2017 The Royal Entomological Society.

  12. Seroprevalence of Toxoplasma gondii infection in captive mammals in three zoos in Mexico City, Mexico

    USDA-ARS?s Scientific Manuscript database

    Antibodies to Toxoplasma gondii were determined in 167 mammals in 3 zoos in Mexico City, Mexico using the modified agglutination test (MAT). Overall, antibodies to T. gondii were found in 89 (53.3%) of the 167 animals tested. Antibodies were found in 35 of 43 wild Felidae: 2 of 2 bobcats (Lynx rufus...

  13. Prediction of optimal safe ground water yield and land subsidence in the Los Banos-Kettleman City area, California, using a calibrated numerical simulation model

    NASA Astrophysics Data System (ADS)

    Larson, K. J.; Başaǧaoǧlu, H.; Mariño, M. A.

    2001-02-01

    Land subsidence caused by the excessive use of ground water resources has traditionally caused serious and costly damage to the Los Banos-Kettleman City area of California's San Joaquin Valley. Although the arrival of surface water from the Central Valley Project has reduced subsidence in recent decades, the growing instability of surface water supplies has refocused attention on the future of land subsidence in the region. This paper uses integrated numerical ground water and land subsidence models to simulate land subsidence caused by ground water overdraft. The simulation model is calibrated using observed data from 1972 to 1998, and the responsiveness of the model to variations in subsidence parameters are analyzed through a sensitivity analysis. A probable future drought scenario is used to evaluate the effect on land subsidence of three management alternatives over the next thirty years. The model reveals that maintaining present practices virtually eliminates unrecoverable land subsidence, but may not be a sustainable alternative because of a growing urban population to the south and concern over the ecological implications of water exportation from the north. The two other proposed management alternatives reduce the dependency on surface water by increasing ground water withdrawal. Land subsidence is confined to tolerable levels in the more moderate of these proposals, while the more aggressive produces significant long-term subsidence. Finally, an optimization model is formulated to determine maximum ground water withdrawal from nine pumping sub-basins without causing irrecoverable subsidence during the forecast period. The optimization model reveals that withdrawal can be increased in certain areas on the eastern side of the study area without causing significant inelastic subsidence.

  14. Measurements of VOCs in Mexico City during the MILAGRO Campaign

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Beyersdorf, A. J.; Blake, N. J.; Meinardi, S.; Atlas, E.; Rowland, F.; Blake, D. R.

    2006-12-01

    During March of 2006 we participated in MILAGRO (Megacities Initiative: Local and Global Research Observations), a multi-platform campaign to measure pollutants in and in outflow from the Mexico City metropolitan area. As part of MILAGRO we collected whole air canister samples at two Mexico City ground sites: the Instituto Mexicano del Petroleo, located in the city, northeast of the center, and the Universidad Technologica de Tecamac, a suburban site approximately 50 km northeast of the city center. Samples were also collected in various other locations throughout Mexico City. Over 300 whole air samples were collected and analyzed for a wide range of volatile organic compounds (VOCs) including methane, carbon monoxide, nonmethane hydrocarbons (NMHCs) and halocarbons. Propane was the most abundant NMHC at both the urban and suburban locations, with mixing ratios frequently in excess of 10 parts per billion at both locations. This is likely the result of the widespread use of liquefied petroleum gas (LPG) of which propane is the major component. For most species, median mixing ratios at the urban sites were significantly greater than at the suburban site. Here we compare results from both urban and suburban locations and also examine the influence of transport on the composition of outflow from Mexico City.

  15. Emissions from Forest Fires near Mexico City

    NASA Technical Reports Server (NTRS)

    Yokelson, R.; Urbanski, S.; Atlas, E.; Toohey, D.; Alvarado, E.; Crounse, J.; Wennberg, P.; Fisher, M.; Wold, C.; Campos, T.; hide

    2007-01-01

    The emissions of NOx (defined as NO (nitric oxide) + NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of fuel burned, from fires in the pine forests that dominate the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The ammonia (NH3) emissions are about average for forest burning. The upper limit for the mass ratio of NOX to volatile organic compounds (VOC) for these MC-area mountain fires was approximately 0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.34, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (approximately 0.068). The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin). The molar emission ratio of HCN to carbon monoxide (CO) for the mountain fires was 0.012 +/- 0.007, which is 2-9 times higher than widely used literature values for biomass burning. The ambient molar ratio HCN/CO in the MC-area outflow is about 0.003 +/- 0.0003. Thus, if only mountain fires emit significant amounts of HCN, these fires may be contributing about 25% of the CO production in the MCarea (approximately 98-100 W and 19-20 N). Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.01 15 and 0.0037) to the PM1/CO mass ratio for the mountain fires (0.133) then suggests that these fires could produce as much as approximately 79-92% of the primary fine particle mass generated in the MC-area. Considering both the uncertainty in the HCN/CO ratios and secondary aerosol formation in the urban and fire emissions implies that about 50 +/- 30% of the "aged" fine particle mass in the March 2006 MC-area outflow could be from these fires.

  16. Remotely-triggered Slip in Mexico City Induced by the September 2017 Mw=7.1 Puebla Earthquake.

    NASA Astrophysics Data System (ADS)

    Solano Rojas, D. E.; Havazli, E.; Cabral-Cano, E.; Wdowinski, S.

    2017-12-01

    Although the epicenter of the September 19th, 2017 Mw=7.1 Puebla earthquake is located 100 km from Mexico City, the earthquake caused severe destruction in the city, leading to life loss and property damage. Mexico City is built on a thick clay-rich sedimentary sequence and, hence, is susceptible to seismic acceleration during earthquakes. The sediment layer also causes land subsidence, at rates as high as 350 mm/yr, and surface faulting. The earthquake damage in the eastern part of the city, characterized by the collapse of several buildings, can be explained by seismic amplification. However, the damage in the southern part of the city, characterized by the collapse of small houses and surface faulting, requires a different explanation. We present here geodetic observations suggesting that the surface faulting in Mexico City triggered by the Puebla earthquake occurred in areas already experiencing differential displacements. Our study is based on Sentinel-1A satellite data from before and after the earthquake (September 17th and 29th, 2017). We process the data using Interferometric Synthetic Aperture Radar (InSAR) to produce a coseismic interferogram. We also identify phase discontinuities that can be interpreted as surface faulting using the phase gradient technique (Price and Sandwell, 1998). The results of our analysis reveal the locations and patterns of coseismic phase discontinuities, mainly in the piedmont of the Sierra de Santa Catarina, which agree with the location of earthquake's damage reported by official and unofficial sources (GCDMX, 2017; OSM, 2017). The observed phase discontinuities also agree well with the location of preexisting, subsidence-related faults identified during 10 years of field surveys (GCDMX, 2017) and coincide with differential displacements identified using a Fast Fourier Transform residual technique on high-resolution InSAR results from 2012 (Solano-Rojas et. al, 2017). We propose that the seismic energy released by the 2017

  17. [Scientific evidence on the legalization of abortion in Mexico City].

    PubMed

    Gayón-Vera, Eduardo

    2010-03-01

    On April 24 2007, abortion before 12 weeks became legal in Mexico City. The arguments for this decision were: diminish the maternal morbidity and mortality, avoid a "severe health problem" and accomplish the women's physical, mental and social well being. To analyze the scientific evidences that support or reject this arguments. Retrospective study realized by bibliographic search of electronic data basis and Internet portals of interested groups. Mexico is considered by the World Health Organization, one of the countries in the world with low maternal mortality rates (<100/100,000 live births). The main causes are: preeclampsia-eclampsia, pregnancy related hemorrhage, complications of pregnancy, delivery and puerperium, and other causes (92.2 to 93.1%). In 2007, the Health Services of Mexico City reported 11 deaths (0.03% of the total maternal deaths) associated with "non-spontaneous abortion". In the hospitals of the Mexican Institute of Social Security, maternal deaths as consequence of induced abortions were, approximately, three every year. The evidences used as arguments in favor of abortion come from studies performed in Sub-Saharan African countries, which do not apply to Mexico. The scientific evidences show that induced abortion has important psychological sequels in women, a higher frequency of illegal drug abuse, alcoholism, child abuse, low birth weight in the following pregnancy, greater risk of subsequent miscarriage and greater mortality rate. There are no scientific evidences to support the arguments used for the legal approval of abortion in Mexico City.

  18. Mexico City's Indios Verdes: Exploring Cultural Processes Using Public Memorials

    ERIC Educational Resources Information Center

    Dixon, Seth

    2010-01-01

    Finding ways to convey current research in cultural geography that is predicated on theoretical frameworks in a manner accessible to high school and undergraduate college students is pedagogically important but difficult in practice. Statues in Mexico City nicknamed the Indios Verdes offer a rich example of fluid cultural dynamics that illustrate…

  19. Biodiesel from waste cooking oil in Mexico City.

    PubMed

    Sheinbaum, Claudia; Balam, Marco V; Robles, Guillermo; Lelo de Larrea, Sebastian; Mendoza, Roberto

    2015-08-01

    The aim of this article is to evaluate the potential use of biodiesel produced from waste cooking oil in Mexico City. The study is divided in two main areas: the analysis of a waste cooking oil collection pilot project conducted in food markets of a Mexico City region; and the exhaust emissions performance of biodiesel blends measured in buses of the Mexico City public bus transportation network (RTP). Results from the waste cooking oil collection pilot project show that oil quantities disposed depend upon the type of food served and the operational practices in a cuisine establishment. Food markets' waste cooking oil disposal rate from fresh oil is around 10%, but with a very high standard deviation. Emission tests were conducted using the Ride-Along-Vehicle-Emissions-Measuring System in two different types of buses while travelling a regular route. Results shows that the use of biodiesel blends reduces emissions only for buses that have exhaust gas recirculation systems, as analysed by repeated measure analysis of variance. The potential use in Mexico City of waste cooking oil for biodiesel is estimated to cover 2175 buses using a B10 blend. © The Author(s) 2015.

  20. Are megacities viable? A cautionary tale from Mexico City.

    PubMed

    Ezcurra, E; Mazari-hiriart, M

    1996-01-01

    This article describes the poor environmental and living conditions in Mexico City due to its huge size. Mexico City's size is a challenge to sustainability, and the outcome is unknown. Mexico City and the geographic basin surrounding it included about 18.5 million population in 1995. The basin and surrounding volcanic ranges include nine major environmental zones. Urban growth followed four stages. Different cultures applied different solutions to water supply problems. The basin shifted from self-sufficiency to reliance on 31% of supplies from external watersheds. The water table is declining and canals are polluted. Irrigated agriculture is disappearing. There is an average water deficit of over 800 million cubic meters per year. Mexico City is actually sinking due to groundwater exploitation. There is bacterial contamination of wells due to improper seals. About 75% of the population has access to wastewater treatment and sanitation, but sewage treatment plants operate at under 50% efficiency and treat only about 7% of the total wastewater. Atmospheric pollution from suspended particles has been a problem for decades. Ozone was the most significant air contaminant in 1994. Lead was the most harmful pollutant in 1986. Air pollutants may be the source of submucosal inflammations. Industrial areas are contaminated with suspended particles and sulfur dioxide. High traffic areas have high carbon monoxide levels. Atmospheric pollution has affected the quality of the rainwater. The city survives by importing food, energy, wood, water, building materials, and other products. The development model aims to improve quality of life. The city has been the center of political power since Aztec times, and its preeminent position forces government action. The author concludes that there are limits to urbanization, which the city is approaching rapidly.

  1. Sources of lead exposure in Mexico City.

    PubMed Central

    Romieu, I; Palazuelos, E; Hernandez Avila, M; Rios, C; Muñoz, I; Jimenez, C; Cahero, G

    1994-01-01

    Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last few years important measures have been implemented to decrease lead exposure, our findings suggest that lead poisoning is still an important problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed. Images Figure 1. PMID:7523102

  2. Sources of lead exposure in Mexico City

    SciTech Connect

    Romieu, I.; Palazuelos, E.; Cahero, G.

    Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last fewmore » years important measures have been implemented problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican Population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed. 37 refs., 1 fig., 8 tabs.« less

  3. Sources of lead exposure in Mexico City.

    PubMed

    Romieu, I; Palazuelos, E; Hernandez Avila, M; Rios, C; Muñoz, I; Jimenez, C; Cahero, G

    1994-04-01

    Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last few years important measures have been implemented to decrease lead exposure, our findings suggest that lead poisoning is still an important problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed.

  4. Variability of Ambient Aerosol in the Mexico City Metropolian Area

    NASA Astrophysics Data System (ADS)

    Onasch, T. B.; Worsnop, D. R.; Canagaratna, M.; Jayne, J. T.; Herndon, S.; Mortimer, P.; Kolb, C. E.; Rogers, T.; Knighton, B.; Dunlea, E.; Marr, L.; de Foy, B.; Molina, M.; Molina, L.; Salcedo, D.; Dzepina, K.; Jimenez, J. L.

    2004-12-01

    The spatial and temporal variations of the ambient aerosol in the Mexico City Metropolitan area was characterized during the springs of 2002 and 2003 using a mobile laboratory equipped with gas and particulate measurement instrumentation. The laboratory was operated at various fixed sites locations in and at the edge of the metropolitan area (Xalostoc, Merced, Cenica, Pedregal, and Santa Ana). Size-resolved aerosol mass and chemical composition was measured with an aerosol mass spectrometer and selected trace gas species (low mass organic compounds, NO, NO2, NOy, O3, SO2, CH2O, NH3, CO2) were measured using a proton transfer reaction mass spectrometer and various optical systems. The aerosol was predominantly organic in composition with lesser amounts of ammonium nitrate, sulfate, and chloride. The organic component was composed of mixed primary and secondary organic compounds. The mass loading and chemical composition of the aerosol was influenced by local and regional air pollution sources and the meteorology in Mexico City. Most urban sites were influenced by a strong diurnal particulate mass trend indicative of primary organic emissions from traffic during early morning and subsequently oxidized/processed organics and ammonium nitrate particles starting in the mid-morning (~9 AM) and continuing throughout the day. Morning traffic-related primary organic emissions were strongest at La Merced (center of Mexico City, located near a busy food market), more subdued at other fixed sites further from the city center, and varied depending upon the day of week and holiday schedules. Particle-bound polycyclic aromatic hydrocarbons were observed within Mexico City fixed sites and were correlated with traffic organic PM emissions. Oxidized organic and ammonium nitrate events occurred during mid-morning at all city sites and were well correlated with gas phase photochemical activity. The daily ammonium nitrate aerosol event occurred later at sites near the city limits

  5. Detection of Old Mine Tunnels in Mexico City Highlands by Electric Resistivity Image Methods

    NASA Astrophysics Data System (ADS)

    Chavez, R. E.; Tejero, A.; Cifuentes-Nava, G.; HernaNdez-Quintero, J.

    2013-12-01

    Electrical Resistivity Tomography (ERT) methods have been applied to study cavities or subsurface subsidence threatening urbanized areas. Unfortunately, ERT-3D techniques carried out on heavily urbanized areas become a difficult task, since parallel ERT arrays cannot be deployed. Then, a conventional regular grid cannot be carried out. We present a subsidence problem located in a densely populated portion of Mexico City highlands. Since the damaged houses are in the middle of a highly populated low-class neighborhood, an unconventional ERT array had to be applied. At first, a ';T'-array formed by two perpendicular transects was applied, deployed within a small alley, that stretched from the house entrance. This study determined a tubular structure beneath the houses following an irregular path at depth. Finally, houses were demolished due to the extensive damaged in their foundations. This made possible to carry out a second ERT-3D study, which included a dipolar array called ';L' and ';Corner' arrays. Such a new work defined a similar tubular structure. The cavity entrance was discovered, when excavations were made, although its precise shape could not be defined. The ERT-3D interpretation contributed to locate and accurately determine the geometrical characteristics of the geological feature that caused the collapse of dwellings.

  6. Sociodemographic and Clinical Characteristics of Centenarians in Mexico City.

    PubMed

    Pedro, Valdés-Corchado; Arturo, Ruiz-Hernández; Alejandro, Pérez-Moreno; Oscar, Rosas-Carrasco

    2017-01-01

    There is little evidence about the demography and health status of adults aged 100 years and over in Latin America and there are no studies in Mexico. To describe the demographic characteristics and health status of centenarians residing in Mexico City. This is a cross-sectional study using a population base of 393 community-dwelling centenarians in Mexico City. A comprehensive geriatric assessment was performed, including demographic information and health status. The mean age of centenarians was 101.82 ± 2.02 years, of whom 44 (9.1%) were semisupercentenarians (105-109 years old) and 5 (0.2%) were supercentenarians (≥110 years old). The female/male ratio was 3.2 : 1. Twelve (4.5%) reside in nursing homes. Women versus men have unfavorable conditions given their criteria: being without a partner, dependence in 1 or more basic activities, dependence in 1 or more instrumental activities, hypertension, cancer, and Parkinson's disease. Nevertheless, as compared to other populations, Mexican centenarians report having good self-perception of health (78.9%), polypharmacy (17.8%), low rate of pain (11.4%), diabetes (4.8%), and dyslipidemia (1.8%). This is the first study in Latin America that describes the social and clinical characteristics of centenarians in Mexico City. This population has a high percentage of malnutrition and osteoarthrosis, a high self-perception of health, low frequency of diabetes, dyslipidemia, cardiovascular disease, and a high frequency of "escapers" (24%).

  7. Land subsidence caused by ground water withdrawal in urban areas

    USGS Publications Warehouse

    Holzer, T.L.; Johnson, A.I.

    1985-01-01

    At least eight urban areas in the world have encountered significant economic impact from land subsidence caused by pumping of ground water from unconsolidated sediment. The areas, most of which are coastal, include Bangkok, Houston, Mexico City, Osaka, San Jose, Shanghai, Tokyo, and Venice. Flooding related to decreased ground elevation is the principal adverse effect of the subsidence. Lesser effects include regional tilting, well-casing failures, "rising" buildings, and ground failure or rupture. Subsidence of most of these urban areas began before the phenomenon was discovered and understood. Thus, the subsidence problems were unanticipated. Methods to arrest subsidence typically have included control of ground water pumping and development of surface water to offset the reductions of ground water pumping. Ground water recharge has also been practiced. Areas threatened by flooding have been protected by extensive networks of dikes and sea walls, locks, and pumping stations to remove storm runoff. ?? 1985 D. Reidel Publishing Company.

  8. [Beliefs about chili pepper consumption and health in Mexico City].

    PubMed

    López-Carrillo, L; Fernández-Ortega M, C; Costa-Dias, R; Franco-Marina, J; Alejandre-Badillo, T

    1995-01-01

    Eating chili peppers is a cultural tradition in Mexico. Controversial characteristics have been empirically associated to chili pepper consumption and human health. In this paper, the beliefs about the health impacts of chili pepper consumption in two independent groups of Mexico City residents are described. The results confirm, on the one hand, that there is a wide variety of health benefits and damages associated with chili pepper consumption, but on the other hand, that the levels of chili pepper consumption are not related to beliefs about its human health impact.

  9. A modeling study of coastal inundation induced by storm surge, sea-level rise, and subsidence in the Gulf of Mexico

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping; Leung, Lai-Yung R.

    The northern coasts of the Gulf of Mexico are highly vulnerable to the direct threats of climate change, such as hurricane-induced storm surge, and such risks can be potentially exacerbated by land subsidence and global sea level rise. This paper presents an application of a coastal storm surge model to study the coastal inundation process induced by tide and storm surge, and its response to the effects of land subsidence and sea level rise in the northern Gulf coast. An unstructured-grid Finite Volume Coastal Ocean Model was used to simulate tides and hurricane-induced storm surges in the Gulf of Mexico.more » Simulated distributions of co-amplitude and co-phase of semi-diurnal and diurnal tides are in good agreement with previous modeling studies. The storm surges induced by four historical hurricanes (Rita, Katrina, Ivan and Dolly) were simulated and compared to observed water levels at National Oceanic and Atmospheric Administration tide stations. Effects of coastal subsidence and future global sea level rise on coastal inundation in the Louisiana coast were evaluated using a parameter “change of inundation depth” through sensitivity simulations that were based on a projected future subsidence scenario and 1-m global sea level rise by the end of the century. Model results suggested that hurricane-induced storm surge height and coastal inundation could be exacerbated by future global sea level rise and subsidence, and that responses of storm surge and coastal inundation to the effects of sea level rise and subsidence are highly nonlinear and vary on temporal and spatial scales.« less

  10. [Obesity or overweight and metabolic syndrome in Mexico City teenagers].

    PubMed

    Cardoso-Saldaña, Guillermo C; Yamamoto-Kimura, Liria; Medina-Urrutia, Aida; Posadas-Sánchez, Rosalinda; Caracas-Portilla, Nacú A; Posadas-Romero, Carlos

    2010-01-01

    aim: To know the metabolic syndrome and its components prevalence in Mexico City adolescents sample. A cross-sectional survey was conducted in 772 men and 1078 women, 12 to 16 years old, from 8 randomly selected public junior high schools in Mexico City. Anthropometric variables, lipids, lipoproteins, Apo AI and B, glucose and insulin were determined. Prevalence of metabolic syndrome was 12.5%, 11.15% in men and 13.5% en women (p ns). The most frequently metabolic syndrome component found in México City adolescents was low HDL-C levels (38%), followed by hypertriglyceridemia (25.5%), hypertension (19.2%), central obesity (11.8%) and elevated fasting glucose (1.7). Except by the hypertriglyceridemia, higher in woman than in men, 28.2% vs. 21.6%, p < 0.001, the prevalence of metabolic syndrome components was similar between males and females. The high prevalence of biochemical and physiological factors of metabolic syndrome, associated with overweight and obesity in Mexico City adolescents, increases the risk of premature development of coronary atherosclerosis and diabetes mellitus in this population.

  11. Study of spirometry in children from Mexico City

    SciTech Connect

    Namihira, D.; Strope, G.L.; Helms, R.W.

    1986-11-01

    A study was conducted in two elementary schools in Mexico City to determine values for pulmonary function tests in school-aged residents of Mexico City. The schools were located in Xalostoc, a highly industrialized area of Mexico City, and San Lorenzo, a suburban area of the city. Although data regarding atmospheric pollution were not available, there is an acknowledged higher level of macroenvironmental air pollution in Xalostoc. Pulmonary function tests were performed on 468 children in San Lorenzo and 405 children in Xalostoc. No differences between residents of the two communities for acute or chronic respiratory conditions were detected by questionnaire.more » The pulmonary function data demonstrate that boys have larger forced vital capacities (FVC) and forced expiratory flows over the middle half of the FVC (FEF25-75) than girls. Slopes of regression lines for FVC but not for FEF25-75 are greater in boys and girls from Xalostoc than in boys and girls from San Lorenzo. This suggests that young children from Xalostoc may experience ill effects of air pollution but develop catch-up growth later. There were no important community or gender effects on slopes of regression lines for height and weight on age. In general, the regression lines for FVC and FEF25-75 were below regression lines reported for children of Mexican ancestry living at sea level.« less

  12. Respiratory tract toxicity in rats exposed to Mexico City air.

    PubMed

    Moss, O R; Gross, E A; James, R A; Janszen, D B; Ross, P W; Roberts, K C; Howard, A M; Harkema, J R; Calderón-Garcidueñas, L; Morgan, K T

    2001-03-01

    The rat has been used extensively as a health sentinel, indicator, or monitor of environmental health hazards, but this model has not been directly validated against human exposures. Humans in Mexico City show upper respiratory tract lesions and evidence of pulmonary damage related to their environmental inhalation exposure. In this study, male and female F344 rats were exposed (23 hr/day) in Mexico City to local Mexico City air (MCA)* for up to seven weeks. Controls were maintained at the same location under filtered air. Prior to these exposures, several steps were taken. First, the nasal passages of normal male rats shipped from the United States and housed in Mexico City were examined for mycoplasma infection; no evidence of infection was found. In addition, a mobile exposure and monitoring system was assembled and, with an ozone (O3) exposure atmosphere, was tested along with supporting histopathology techniques and analysis of rat nasal and lung tissues. Last, the entire exposure model (equipment and animals) was transported to Mexico City and validated for a three-week period. During the seven-week study there were 18 one-hour intervals during which the average O3 concentration of MCA in the exposure chamber exceeded the US National Ambient Air Quality Standard (NAAQS) of 0.120 ppm 03 (hourly average, not to be exceeded more than once per year). This prolonged exposure of healthy F344 rats to MCA containing episodically low to moderate concentrations of 03 (as well as other urban air pollutants) did not induce inflammatory or epithelial lesions in the nasal airways or lung as measured by qualitative histologic techniques or quantitative morphometric techniques. These findings agree with those of previous controlled O3 inhalation studies, but they are in contrast to reports indicating that O3-polluted MCA causes significant nasal mucosal injury in adults and children living in southwestern Mexico City. Taken together, these findings may suggest that human

  13. The ground subsidence anomaly investigation around Ambala, India by InSAR and spatial analyses: Why and how the Ambala city behaves as the most significant subsidence region in the Northwest India?

    NASA Astrophysics Data System (ADS)

    Kim, J.; Lin, S. Y.; Tsai, Y.; Singh, S.; Singh, T.

    2017-12-01

    A large ground deformation which may be caused by a significant groundwater depletion of the Northwest India Aquifer has been successfully observed throughout space geodesy techniques (Tsai et al, 2016). Employing advanced time-series ScanSAR InSAR analysis and Gravity Recovery and Climate Experiment (GRACE) satellites data, it revealed 400-km wide huge ground deformation in and around Haryana. It was further notified that the Ambala city located in northern Haryana district shown the most significant ground subsidence with maximum cumulative deformation up to 0.2 meters within 3 years in contrast to the nearby cities such as Patiala and Chandigarh that did not present similar subsidence. In this study, we investigated the details of "Ambala Anomaly" employing advanced time-series InSAR and spatial analyses together with local geology and anthropogenic contexts and tried to identify the factors causing such a highly unique ground deformation pattern. To explore the pattern and trend of Ambala' subsidence, we integrated the time-series deformation results of both ascending L-band PALSAR-1 (Phased Array type L-band Synthetic Aperture Radar) from 2007/1 to 2011/1 and descending C-band ASAR (Advanced Synthetic Aperture Radar) from 2008/9 to 2010/8 to process the 3D decomposition, expecting to reveal the asymmetric movement of the surface. In addition. The spatial analyses incorporating detected ground deformations and local economical/social factors were then applied for the interpretation of "Ambala Anomaly". The detailed interrelationship of driving factors of the "Ambala Anomaly" and the spatial pattern of corresponding ground subsidence will be further demonstrated. After all, we determined the uniqueness of Ambala subsidence possibly be driven by both anthropogenic behaviors including the rapid growth rate of population and constructing of industrial centers as well as the natural geological characteristics and sediment deposition.

  14. [Sanitary control of food in Mexico city].

    PubMed

    Sartí-Gutiérrez, E J; Parrilla-Cerrillo, C; Vázquez-Barojas, S; Kawashima-Hashimoto, L; Farías-Rodríguez, A; García-Juárez, C

    1989-01-01

    This work was undertaken as to avoid health risks to tourism in the "XIIth Soccer World Cup, Mexico 86". The above project was carried out through proper quality control of foods, drinking water as well as a definite care of personal hygiene of all those involved in the catering business (132 restaurants were included). The mentioned report informs only of the work of the National Public Health Laboratory in the Sanitary Epidemiological Program. The following products were analyzed: 133 water samples, 272 animated and nonliving surfaces, and 399 foods. Twenty seven percent of water samples were rejected, as well as 85% of the different surfaces and 60% of the food samples. High counts of mesophilic aerobics, followed by coliforms, S. aureus and Salmonella sp., were the principal specimens encountered. Therefore, it was suggested the permanent development of a sanitary epidemiological program.

  15. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    NASA Astrophysics Data System (ADS)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  16. 76 FR 58772 - Safety & Security Trade Mission; Mexico City and Monterrey, Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-22

    ... dinner at a local restaurant--group transportation will be provided. On February 1, participants will.... Group dinner at local restaurant (no host). February 1 Mexico City/Monterrey. Breakfast (no host... ability to meet certain conditions and to satisfy the selection criteria as outlined below. This mission...

  17. Survey of aflatoxins in maize tortillas from Mexico City.

    PubMed

    Castillo-Urueta, Pável; Carvajal, Magda; Méndez, Ignacio; Meza, Florencia; Gálvez, Amanda

    2011-01-01

    In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12 µg kg⁻¹ total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3-385 µg kg⁻¹ or values below the limit of quantification (12 µg kg⁻¹ and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB1 (12.1 µg kg⁻¹); AFB2 (2.7 µg kg⁻¹); AFG1 (64.1 µg kg⁻¹) and AFG2 (3.7 µg kg⁻¹), and total AF (20.3 µg kg⁻¹).

  18. [Migration expectations among nursing students in Mexico City].

    PubMed

    Rosales-Martínez, Yetzi; Nigenda, Gustavo; Galárraga, Omar; Ruiz-Larios, José Arturo

    2010-01-01

    To analyze the factors associated with the expectations to migrate abroad among nursing students in Mexico City. A cross-sectional study was conducted with a non-random sample of 420 students. A logistic regression model was estimated. A total of 69% of the informants expressed their intention to move abroad, to look for employment (65%) and/or to continue their studies (26%). Of those, 50% would choose Canada as their destination, followed by Spain and the United States. The variables associated with migration expectations were: age, income, having relatives abroad, and perception of poor labor conditions and low wages in Mexico. Results are consistent with international literature. Low wages, poor labor conditions and the limited possibilities for professional development in Mexico are factors that contribute to generate migration expectations among nursing students. Additionally, optimistic perceptions about the job market and the labor demand in more developed countries heighten expectations to migrate.

  19. Land subsidence and recovery in the Albuquerque Basin, New Mexico, 1993–2014

    USGS Publications Warehouse

    Driscoll, Jessica M.; Brandt, Justin T.

    2017-08-14

    The Albuquerque Bernalillo County Water Utility Authority (ABCWUA) drinking water supply was almost exclusively sourced from groundwater from within the Albuquerque Basin before 2008. In 2008, the San Juan-Chama Drinking Water Project (SJCDWP) provided surface-water resources to augment the groundwater supply, allowing for a reduction in groundwater pumping in the Albuquerque Basin. In 2013, the U.S. Geological Survey, in cooperation with the ABCWUA, began a study to measure and compare aquifer-system and land-surface elevation change before and after the SJCDWP in 2008. Three methods of data collection with different temporal and spatial resolutions were used for this study: (1) aquifer-system compaction data collected continuously at a single extensometer from 1994 to 2013; (2) land-surface elevation change from Global Positioning System (GPS) surveys of a network of monuments collected in 1994–95, 2005, and 2014; and (3) spatially distributed Interferometric Synthetic Aperture Radar (InSAR) satellite data from 1993 to 2010. Collection of extensometer data allows for direct and continuous measurement of aquifer-system compaction at the extensometer location. The GPS surveys of a network of monuments allow for periodic measurements of land-surface elevation change at monument locations. Interferograms are limited in time by lifespan of the satellite, orbital pattern, and data quality but allow for measurement of gridded land-surface elevation change over the study area. Each of these methods was employed to provide a better understanding of aquifer-system compaction and land-surface elevation change for the Albuquerque Basin.Results do not show large magnitudes of subsidence in the Albuquerque Basin. High temporal-resolution but low spatial-resolution data measurements of aquifer-system compaction at the Albuquerque extensometer show elastic aquifer-system response to recovering groundwater levels. Results from the GPS survey of the network of monuments show

  20. Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

    PubMed Central

    2011-01-01

    Background Worldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City. Methods Included in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level). Results Although a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high

  1. Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology.

    PubMed

    Pérez-Saldivar, María Luisa; Fajardo-Gutiérrez, Arturo; Bernáldez-Ríos, Roberto; Martínez-Avalos, Armando; Medina-Sanson, Aurora; Espinosa-Hernández, Laura; Flores-Chapa, José de Diego; Amador-Sánchez, Raquel; Peñaloza-González, José Gabriel; Alvarez-Rodríguez, Francisco Javier; Bolea-Murga, Victoria; Flores-Lujano, Janet; Rodríguez-Zepeda, María Del Carmen; Rivera-Luna, Roberto; Dorantes-Acosta, Elisa María; Jiménez-Hernández, Elva; Alvarado-Ibarra, Martha; Velázquez-Aviña, Martha Margarita; Torres-Nava, José Refugio; Duarte-Rodríguez, David Aldebarán; Paredes-Aguilera, Rogelio; Del Campo-Martínez, María de Los Ángeles; Cárdenas-Cardos, Rocío; Alamilla-Galicia, Paola Hillary; Bekker-Méndez, Vilma Carolina; Ortega-Alvarez, Manuel Carlos; Mejia-Arangure, Juan Manuel

    2011-08-17

    Worldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City. Included in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level). Although a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive

  2. Connecting Urbanization to Precipitation: the case of Mexico City

    NASA Astrophysics Data System (ADS)

    Georgescu, Matei

    2017-04-01

    Considerable evidence exists illustrating the influence of urban environments on precipitation. We revisit this theme of significant interest to a broad spectrum of disciplines ranging from urban planning to engineering to urban numerical modeling and climate, by detailing the simulated effect of Mexico City's built environment on regional precipitation. Utilizing the Weather Research and Forecasting (WRF) system to determine spatiotemporal changes in near-surface air temperature, precipitation, and boundary layer conditions induced by the modern-day urban landscape relative to presettlement conditions, I mechanistically link the built environment-induced increase in air temperature to simulated increases in rainfall during the evening hours. This simulated increase in precipitation is in agreement with historical observations documenting observed rainfall increase. These results have important implications for understanding the meteorological conditions leading to the widespread and recurrent urban flooding that continues to plague the Mexico City Metropolitan Area.

  3. Aedes albopictus in Allende City, Nuevo Léon, Mexico.

    PubMed

    Pesina, H O; Hernandez, R M; Valdez Rodriguez, M A

    2001-12-01

    Nuevo León was the only 1 of the 3 northeastern states of Mexico where Aedes albopictus previously had not been shown to occur. However, of 195 samples of larval Aedes received during 1997 from the State Health Laboratory for identification from the 7th Sanitary District, Allende City, Nuevo León, 53 (27.2%) were identified as Ae. albopictus.

  4. Improving air quality in megacities: Mexico City case study.

    PubMed

    Molina, Luisa T; Molina, Mario J

    2004-06-01

    The development and effective implementation of solutions to the air pollution problems in the Mexico City Metropolitan Area is essential to guarantee the health and welfare of its inhabitants. To achieve this, it is essential to have the active and informed participation of the civil society, the academic community, the private sector, and the government, because dealing with pollution requires the use of different strategies in multiple fields of action. The Mexico City case study brings together health, transportation, administration, and many other interdisciplinary approaches to understanding and defeating air pollution. Although focused on the Mexico City area, the work conducted under this case study has significance for developing nations generally. Although policies to reduce air pollution should be based on the best available scientific knowledge, political will and capacity must transform this knowledge into action. This case study has developed a series of recommendations emphasizing the interaction between different disciplines that have provided the foundation for the 10-year air quality management program prepared by the Mexican Metropolitan Environmental Commission.

  5. Mexico City Air Quality Research Initiative; Volume 5, Strategic evaluation

    SciTech Connect

    NONE

    1994-03-01

    Members of the Task HI (Strategic Evaluation) team were responsible for the development of a methodology to evaluate policies designed to alleviate air pollution in Mexico City. This methodology utilizes information from various reports that examined ways to reduce pollutant emissions, results from models that calculate the improvement in air quality due to a reduction in pollutant emissions, and the opinions of experts as to the requirements and trade-offs that are involved in developing a program to address the air pollution problem in Mexico City. The methodology combines these data to produce comparisons between different approaches to improving Mexico City`smore » air quality. These comparisons take into account not only objective factors such as the air quality improvement or cost of the different approaches, but also subjective factors such as public acceptance or political attractiveness of the different approaches. The end result of the process is a ranking of the different approaches and, more importantly, the process provides insights into the implications of implementing a particular approach or policy.« less

  6. 33 CFR 334.763 - Naval Support Activity Panama City; Gulf of Mexico; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... City; Gulf of Mexico; restricted area. 334.763 Section 334.763 Navigation and Navigable Waters CORPS OF....763 Naval Support Activity Panama City; Gulf of Mexico; restricted area. (a) The area. The area is... enforced by the Commanding Officer, Naval Support Activity, Panama City Florida, and such agencies as he...

  7. 33 CFR 334.763 - Naval Support Activity Panama City; Gulf of Mexico; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... City; Gulf of Mexico; restricted area. 334.763 Section 334.763 Navigation and Navigable Waters CORPS OF....763 Naval Support Activity Panama City; Gulf of Mexico; restricted area. (a) The area. The area is... enforced by the Commanding Officer, Naval Support Activity, Panama City Florida, and such agencies as he...

  8. 3 CFR - Mexico City Policy and Assistance for Voluntary Population Planning

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Mexico City Policy and Assistance for Voluntary... City Policy and Assistance for Voluntary Population Planning Memorandum for the Secretary of State [and... Reagan of what has become known as the “Mexico City Policy” directed the United States Agency for...

  9. Concentrations of persistent organic pollutants (POPs) in human blood samples from Mexico City, Mexico.

    PubMed

    Orta-García, Sandra; Pérez-Vázquez, Francisco; González-Vega, Carolina; Varela-Silva, José Antonio; Hernández-González, Lidia; Pérez-Maldonado, Iván

    2014-02-15

    Studies in Mexico have demonstrated exposure to persistent organic pollutants (POPs) in people living in different sites through the country. However, studies evaluating exposure to POPs in people living in Mexico City (one of most contaminated places in the world) are scarce. Therefore, the aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) in the blood as exposure biomarkers in people living in Mexico City. A total of 123 participants (blood donors aged 20-60 years) were recruited during 2010 in Mexico City. Quantitative analyses of blood samples were performed using gas chromatography coupled with mass spectrometry. Levels of the assessed compounds ranged from non-detectable (

  10. Sociodemographic and Clinical Characteristics of Centenarians in Mexico City

    PubMed Central

    Pedro, Valdés-Corchado; Arturo, Ruiz-Hernández; Alejandro, Pérez-Moreno

    2017-01-01

    Background There is little evidence about the demography and health status of adults aged 100 years and over in Latin America and there are no studies in Mexico. Objectives To describe the demographic characteristics and health status of centenarians residing in Mexico City. Methods This is a cross-sectional study using a population base of 393 community-dwelling centenarians in Mexico City. A comprehensive geriatric assessment was performed, including demographic information and health status. Results The mean age of centenarians was 101.82 ± 2.02 years, of whom 44 (9.1%) were semisupercentenarians (105–109 years old) and 5 (0.2%) were supercentenarians (≥110 years old). The female/male ratio was 3.2 : 1. Twelve (4.5%) reside in nursing homes. Women versus men have unfavorable conditions given their criteria: being without a partner, dependence in 1 or more basic activities, dependence in 1 or more instrumental activities, hypertension, cancer, and Parkinson's disease. Nevertheless, as compared to other populations, Mexican centenarians report having good self-perception of health (78.9%), polypharmacy (17.8%), low rate of pain (11.4%), diabetes (4.8%), and dyslipidemia (1.8%). Conclusions This is the first study in Latin America that describes the social and clinical characteristics of centenarians in Mexico City. This population has a high percentage of malnutrition and osteoarthrosis, a high self-perception of health, low frequency of diabetes, dyslipidemia, cardiovascular disease, and a high frequency of “escapers” (24%). PMID:28904969

  11. The economic impact of Mexico City's smoke-free law.

    PubMed

    López, Carlos Manuel Guerrero; Ruiz, Jorge Alberto Jiménez; Shigematsu, Luz Myriam Reynales; Waters, Hugh R

    2011-07-01

    To evaluate the economic impact of Mexico City's 2008 smoke-free law--The Non-Smokers' Health Protection Law on restaurants, bars and nightclubs. We used the Monthly Services Survey of businesses from January 2005 to April 2009--with revenues, employment and payments to employees as the principal outcomes. The results are estimated using a differences-in-differences regression model with fixed effects. The states of Jalisco, Nuevo León and México, where the law was not in effect, serve as a counterfactual comparison group. In restaurants, after accounting for observable factors and the fixed effects, there was a 24.8% increase in restaurants' revenue associated with the smoke-free law. This difference is not statistically significant but shows that, on average, restaurants did not suffer economically as a result of the law. Total wages increased by 28.2% and employment increased by 16.2%. In nightclubs, bars and taverns there was a decrease of 1.5% in revenues and an increase of 0.1% and 3.0%, respectively, in wages and employment. None of these effects are statistically significant in multivariate analysis. There is no statistically significant evidence that the Mexico City smoke-free law had a negative impact on restaurants' income, employees' wages and levels of employment. On the contrary, the results show a positive, though statistically non-significant, impact of the law on most of these outcomes. Mexico City's experience suggests that smoke-free laws in Mexico and elsewhere will not hurt economic productivity in the restaurant and bar industries.

  12. The economic impact of Mexico City's smoke-free law

    PubMed Central

    Guerrero López, Carlos Manuel; Jiménez Ruiz, Jorge Alberto; Reynales Shigematsu, Luz Myriam

    2011-01-01

    Objective To evaluate the economic impact of Mexico City's 2008 smoke-free law—The Non-Smokers' Health Protection Law on restaurants, bars and nightclubs. Material and methods We used the Monthly Services Survey of businesses from January 2005 to April 2009—with revenues, employment and payments to employees as the principal outcomes. The results are estimated using a differences-in-differences regression model with fixed effects. The states of Jalisco, Nuevo León and México, where the law was not in effect, serve as a counterfactual comparison group. Results In restaurants, after accounting for observable factors and the fixed effects, there was a 24.8% increase in restaurants' revenue associated with the smoke-free law. This difference is not statistically significant but shows that, on average, restaurants did not suffer economically as a result of the law. Total wages increased by 28.2% and employment increased by 16.2%. In nightclubs, bars and taverns there was a decrease of 1.5% in revenues and an increase of 0.1% and 3.0%, respectively, in wages and employment. None of these effects are statistically significant in multivariate analysis. Conclusions There is no statistically significant evidence that the Mexico City smoke-free law had a negative impact on restaurants' income, employees' wages and levels of employment. On the contrary, the results show a positive, though statistically non-significant, impact of the law on most of these outcomes. Mexico City's experience suggests that smoke-free laws in Mexico and elsewhere will not hurt economic productivity in the restaurant and bar industries. PMID:21292808

  13. GEOLOGICAL-GEOMORPHOLOGICAL ANALYSIS OF THE REGION OF GUADALAJARA, MEXICO AND ITS RELATION WITH SUBSIDENCE HAZARDS

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Delgado-Argote, L. A.; Nunez-Cornu, F. J.

    2009-12-01

    The Metropolitan Area of Guadalajara (MAG) was built over pumice deposits generated during Quaternary activity in the Sierra la Primavera, that covered a thick sequence of basaltic, dacitic, rhyolitic lava flows, ignimbrites and fluvial-lacustrine deposits. The most complete stratigraphic section is observed in different sections of the Rio Grande de Santiago cliff, located north of the city. Five distinctive geoforms were identified: 1) the cliff of the Rio Grande de Santiago (CRGS) is a tectonic erosive depression with average depth of 500 m and 3.5 km width. Structurally, in the San Gaspar zone, south of the union of Verde river with Santiago river, we identified normal faults with left-lateral motion and oriented 191°/89° on basaltic lavas. In the Colimilla dam, 1297 meters above sea level, we observed lateral faulting with normal component (267°/81°) where jumps as high as 30 m were observed. Lava flows are sheared parallel to the Verde river. In the Puente Arcediano zone, where the base of the sequence is apparent, faults have a dominant orientation of 188°/75° on andesitic flows, whereas on pumice ignimbrites they show a shearing with a direction of 92°/84° parallel to the Verde river. 2) The Sierra la Primavera, to the southwest of MAG is a caldera formed by a series of domes, flows, and pyroclastic deposits with rhyolitic composition. 3) The southern Guadalajara volcanic chain system, which is formed by several volcanic cones and flows of basaltic-andesitic composition and Plio-Pleistocene age, oriented NW-SE, developed over the San Gaspar ignimbrite (4.8 m.a.). 4) Los Colomos and Alcalde-Barranquitas cliff system, which form dendrite networks developed on pumice deposits, where most of the cliffs were deep and narrow. The origin of the cliffs might be associated with observed faults or fracture zones in the CRGS. 5) Wavy plains of Atemajac and Tesistán valleys, which are characterized by hills and wide plains. The system of cliffs controlled the

  14. Epidemiology of major depression in four cities in Mexico.

    PubMed

    Slone, Laurie B; Norris, Fran H; Murphy, Arthur D; Baker, Charlene K; Perilla, Julia L; Diaz, Dayna; Rodriguez, Francisco Gutiérrez; Gutiérrez Rodriguez, José de Jesús

    2006-01-01

    Analyses were conducted to estimate lifetime and current prevalence of major depressive disorder (MDD) for four representative cities of Mexico, to identify variables that influence the probability of MDD, and to further describe depression in Mexican culture. A multistage probability sampling design was used to draw a sample of 2,509 adults in four different regions of Mexico. MDD was assessed according to DSM-IV criteria by using the Composite International Diagnostic Interview collected by trained lay interviewers. The prevalence of MDD in these four cities averaged 12.8% for lifetime and 6.1% for the previous 12 months. MDD was highly comorbid with other mental disorders. Women were more likely to have lifetime MDD than were men. Being divorced, separated, or widowed (compared to married or never married) and having experienced childhood trauma were related to higher lifetime prevalence but not to current prevalence. In addition, age and education level were related to current 12-month MDD. Data on the profile of MDD in urban Mexico are provided. This research expands our understanding of MDD across cultures.

  15. Assessing air quality index awareness and use in Mexico City.

    PubMed

    Borbet, Timothy C; Gladson, Laura A; Cromar, Kevin R

    2018-04-23

    The Mexico City Metropolitan Area has an expansive urban population and a long history of air quality management challenges. Poor air quality has been associated with adverse pulmonary and cardiac health effects, particularly among susceptible populations with underlying disease. In addition to reducing pollution concentrations, risk communication efforts that inform behavior modification have the potential to reduce public health burdens associated with air pollution. This study investigates the utilization of Mexico's IMECA risk communication index to inform air pollution avoidance behavior among the general population living in the Mexico City Metropolitan Area. Individuals were selected via probability sampling and surveyed by phone about their air quality index knowledge, pollution concerns, and individual behaviors. The results indicated reasonably high awareness of the air quality index (53% of respondents), with greater awareness in urban areas, among older and more educated individuals, and for those who received air quality information from a healthcare provider. Additionally, behavior modification was less influenced by index reports as it was by personal perceptions of air quality, and there was no difference in behavior modification among susceptible and non-susceptible groups. Taken together, these results suggest there are opportunities to improve the public health impact of risk communication through an increased focus on susceptible populations and greater encouragement of public action in response to local air quality indices.

  16. Prevalence of Human Papillomavirus in Women from Mexico City

    PubMed Central

    López Rivera, María Guadalupe; Flores, Maria Olivia Medel; Villalba Magdaleno, José D'Artagnan; Sánchez Monroy, Virginia

    2012-01-01

    Introduction. Cervical cancer is the most common cancer among Mexican women. The goal of the present study was to determine the prevalence and distribution of HPV types in women from Mexico City. Methods. Our study was conducted in the Clinica de Especialidades de la Mujer de la Secretaría de la Defensa Nacional, Mexico. Random samples were taken from 929 healthy women requesting a cervical Papanicolaou examination. Detection and genotyping of HPV were performed by multiplex PCR, with the HPV4A ACE Screening kit (Seegene). Results. 85 of nine hundred twenty-nine women (9.1%) were infected with HPV. Of HPV-positive women, 99% and 1% had high- and low-risk HPV genotypes, respectively. The prevalence of the 16 high-risk (HR) HPV types that were screened was 43% : 42% (18) were HPV positive and 14% (16) were HPV positive, which includes coinfection. Multiple infections with different viral genotypes were detected in 10% of the positive cases. Abnormal cervical cytological results were found in only 15.3% of HPV-positive women, while 84.7% had normal cytological results. Conclusions. We found a similar prevalence of HPV to previous studies in Mexico. The heterogeneity of the HPV genotype distribution in Mexico is evident in this study, which found a high frequency of HPV HR genotypes, the majority of which were HPV 18. PMID:22811590

  17. [Prostitution and AIDS in the city of Mexico].

    PubMed

    Uribe-Zúñiga, P; Hernández-Tepichín, G; del Río-Chiriboga, C; Ortiz, V

    1995-01-01

    Since 1987 The National AIDS Council in Mexico (CONASIDA), has conducted research projects among female commercial sex workers (CSW), who are seen at the AIDS Information Centers. Through these studies, we have been able to find out how different issues influence commercial sex work in Mexico City. Since the beginning of our own studies in 1989, HIV prevalence in this particular group has remained low (0.04%-0.2%). Factors found to be associated with condom use were: educational level, not having children, more experience in sex work and younger age. Condom use was reported by 88% of the women; however, qualitative information and high STD prevalence rates suggest a much lower condom use. Mandatory HIV testing is not useful as a preventive measure among sex workers. Persuasive and structural interventions must be implemented in accordance with local and legal situations.

  18. Reference values of olfactory function for Mexico City inhabitants.

    PubMed

    Guarneros, Marco; Hudson, Robyn; López-Palacios, Martha; Drucker-Colín, René

    2015-01-01

    Olfactory testing is useful in the differential diagnosis of age-related pathologies. To provide baseline reference values for clinical use in Mexico City we investigated the relation between olfactory capabilities and the principal population parameters of age, sex, and smoking habits in a large sample of healthy inhabitants. We applied the internationally recognized and commercially available Sniffin' Sticks test battery to 916 men and women from across the adult life span. The Sniffin' Sticks test evaluates three key aspects of olfactory function: 1) ability to detect an odor, 2) to discriminate between odors, and 3) to identify odors. We found a significant decline in olfactory function from the 5th decade of age, and that detection threshold was the most sensitive measure of this. We did not find a significant difference between men and women or between smokers and non-smokers. In confirmation of our previous studies of the negative effect of air pollution on olfactory function, Mexico City inhabitants had poorer overall performance than corresponding subjects previously tested in the neighboring but less polluted Mexican state of Tlaxcala. Although we basically confirm findings on general demographic patterns of olfactory performance from other countries, we also demonstrate the need to take into account local cultural, environmental and demographic factors in the clinical evaluation of olfactory performance of Mexico City inhabitants. The Sniffin' Sticks test battery, with some adjustment of stimuli to correspond to Mexican culture, provides an easily administered means of assessing olfactory health. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

  19. Emerging patterns of crack use in Mexico City.

    PubMed

    Valdez, Avelardo; Kaplan, Charles; Nowotny, Kathryn M; Natera-Rey, Guillermina; Cepeda, Alice

    2015-08-01

    Recent studies in Mexico have documented a significant increase in crack cocaine use, indicating the potential for an emerging drug epidemic. Ethnographic observations and interviews were used describe the profiles and patterns of use among street-recruited crack users in Mexico City. The data came from an international research collaboration funded by the National Institutes of Health. A polythetic typology was developed based on five dimensions central to categorizing patterns of crack use behavior: frequency of use, duration of use, context, social networks, and social contracts. Four types of users were discovered applying these dimensions: dabblers, stable users, crack heads, and old heads. Although several similarities were documented between patterns of crack use in Mexico and those in the United States and Western Europe, several key aspects distinguished crack users in this population: (1) self-regulated use; (2) non-linear progression of crack; and (3) the influence of the dimensions pertaining to setting, social networks, and social contract as contributing to understanding of the previous two. Further, we provide a discussion of how specific contextual factors in Mexico may be giving rise to these emerging patterns. Compared to the U.S. and Europe, this study finds that the majority of crack users were able to self-regulate their use without major disruption to daily social functioning. As crack use spreads in Mexico and other Latin American countries, we need to recognize the importance of social context in developing more tailored health and social responses that are specific to these developing countries. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Where do Property Rights Matter More? Explaining the Variation in Demand for Property Titles across Cities in Mexico

    PubMed Central

    Monkkonen, Paavo

    2016-01-01

    Summary This paper examines the variation in the value of property rights to housing in Mexico, focusing specifically on differences between urban housing markets. Roughly 30% of owner-occupied houses in Mexico do not have a proper deed. Houses with no deed are estimated to be five percent less valuable than otherwise similar houses with a full deed, yet this premium varies widely across cities. I match data from the 2012 and 2014 National Survey of Household Incomes and Expenditures to different sources of city-level data in order to examine hypotheses explaining this variation in a multilevel regression framework. I find that deeds are valued more in cities with more highly educated residents, more political competition, and more voting. Measures of local economic activity, degree of informality, and the regulatory bureaucracy are not associated with higher value to full property rights. Additionally, I find that more educated households value deeds more, and having a deed is more valuable for larger houses in neighborhoods with less vacancy and higher infrastructure quality. Based on these results, I suggest funds to subsidize titling should be redirected to places where titles are worth more. More broadly, I suggest policymakers reconsider framing property-titling programs as poverty alleviation. Low-income households would benefit more from subsidies for improvements to housing and residential infrastructure. At the same time, the federal government should further push to reduce the costs of transferring property. PMID:27616806

  1. Physical Exposure to Seismic Hazards of Health Facilities in Mexico City, Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez, S. M.; Novelo Casanova, D.

    2010-12-01

    Although health facilities are essential infrastructure during disasters and emergencies, they are also usually highly vulnerable installations in the case of the occurrence of large and major earthquakes. Hospitals are one of the most complex critical facilities in modern cities and they are used as first response in emergency situations. The operability of a hospital must be maintained after the occurrence of a local strong earthquake in order to satisfy the need for medical care of the affected population. If a health facility is seriously damaged, it cannot fulfill its function when most is needed. In this case, hospitals become a casualty of the disaster. To identify the level of physical exposure of hospitals to seismic hazards in Mexico City, we analyzed their geographic location with respect to the seismic response of the different type of soils of the city from past earthquakes, mainly from the events that occurred on September 1985 (Ms= 8.0) and April 1989 (Ms= 6.9). Seismic wave amplification in this city is the result of the interaction of the incoming seismic waves with the soft and water saturated clay soils, on which a large part of Mexico City is built. The clay soils are remnants of the lake that existed in the Valley of Mexico and which has been drained gradually to accommodate the growing urban sprawl. Hospital facilities were converted from a simple database of names and locations into a map layer of resources. This resource layer was combined with other map layers showing areas of seismic microzonation in Mexico City. This overlay was then used to identify those hospitals that may be threatened by the occurrence of a large or major seismic event. We analyzed the public and private hospitals considered as main health facilities. Our results indicate that more than 50% of the hospitals are highly exposed to seismic hazards. Besides, in most of these health facilities we identified the lack of preventive measures and preparedness to reduce their

  2. Simulated Climate Impacts of Mexico City's Historical Urban Expansion

    NASA Astrophysics Data System (ADS)

    Benson-Lira, Valeria

    Urbanization, a direct consequence of land use and land cover change, is responsible for significant modification of local to regional scale climates. It is projected that the greatest urban growth of this century will occur in urban areas in the developing world. In addition, there is a significant research gap in emerging nations concerning this topic. Thus, this research focuses on the assessment of climate impacts related to urbanization on the largest metropolitan area in Latin America: Mexico City. Numerical simulations using a state-of-the-science regional climate model are utilized to address a trio of scientifically relevant questions with wide global applicability. The importance of an accurate representation of land use and land cover is first demonstrated through comparison of numerical simulations against observations. Second, the simulated effect of anthropogenic heating is quantified. Lastly, numerical simulations are performed using pre-historic scenarios of land use and land cover to examine and quantify the impact of Mexico City's urban expansion and changes in surface water features on its regional climate.

  3. Impact of trash burning on air quality in Mexico City.

    PubMed

    Hodzic, A; Wiedinmyer, C; Salcedo, D; Jimenez, J L

    2012-05-01

    Air pollution experienced by expanding urban areas is responsible for serious health effects and death for millions of people every year. Trash burning is a common disposal method in poor areas, yet it is uncontrolled in many countries, and its contribution to air pollution is unclear due to uncertainties in its emissions. Here we develop a new trash burning emission inventory for Mexico City based on inverse socioeconomic levels and recently measured emission factors, and apply a chemistry-transport model to analyze the effects on pollutant concentrations. Trash burning is estimated to emit 25 tons of primary organic aerosols (POA) per day, which is comparable to fossil fuel POA emissions in Mexico City, and causes an increase in average organic aerosol concentrations of ∼0.3 μg m(-3) downtown and up to 2 μg m(-3) in highly populated suburbs near the sources of emission. An evaluation using submicrometer antimony suggests that our emission estimates are reasonable. Mitigation of trash burning could reduce the levels of organic aerosols by 2-40% and those of PM(2.5) by 1-15% over the metropolitan area. The trash burning contributions to carbon monoxide, nitrogen oxides, and volatile organic compounds were found to be very small (<3%), and consequently the contributions to secondary nitrate, sulfate, and secondary organic aerosols are also very small. © 2012 American Chemical Society

  4. Childcare needs of female street vendors in Mexico City.

    PubMed

    Hernandez, P; Zetina, A; Tapia, M; Ortiz, C; Soto, I C

    1996-06-01

    This article reports on strategies developed by female street vendors (vendedoras ambulantes) in Mexico City to ensure the care of their young children in the absence of a specific and operational government policy to fulfil this need. The information concerning child care and health was gathered by a survey of 426 street traders selected by multi-stage random cluster sampling in four of the administrative districts (delegaciones politicas) of Mexico City during 1990. It was found that, as mothers of young children, street vendors most frequently looked after their children personally on the street or left them with other members of the family. Related factors were availability of alternative child care providers in the family, the age of the children and working conditions of the mother. Children who remained on the streets with their mothers suffered more frequently from gastro-intestinal diseases and accidents than the national average. The incidence of acute respiratory diseases, however, was similar in the cases of maternal care in the street and care by family members in another environment. Existing public health measures show a greater concern for the health of food consumers than that of workers in this area. Current public policy seeks to regulate street vending activities and to concentrate traders in ad hoc areas and facilities. Our research results document the need for actions that can contribute to an improvement in the care and health conditions of these young children.

  5. Characterization of air pollution in Mexico City by remote sensing

    NASA Astrophysics Data System (ADS)

    Grutter, Michel; Arellano, Josue; Bezanilla, Alejandro; Friedrich, Martina; Plaza, Eddy; Rivera, Claudia; Stremme, Wolfgang

    2014-05-01

    Megacities, like the Mexico City Metropolitan Area, are home to a large fraction of the population of the world and a consequence is that they are one of the biggest sources of contaminants and greenhouse gases emitted to the atmosphere. The pollution is visible form space through remote sensing instruments, however, satellite observations like those with NADIR viewing geometries have decreased sensitivity near the Earth's surface and the analytical algorithms are in generally optimized to detect pollution plumes in the free troposphere or above. Ground-based observations are thus necessary in order to reduce uncertainties from satellite products. As we will show, Mexico City and its surroundings is well characterized by ground-based remote sensing measurements like from two stations with solar-absorption FTIR spectrometers and a newly formed network of MAX-DOAS and LIDAR instruments. Examples will be provided of how the evolution of the mixing-layer height is characterized and the vertical column densities and profiles of gases in and outside the urban area are continuously monitored. The combination of ground-based and space-borne measurements are used to improve the current knowledge in the spatial and temporal distribution of key pollutants from this megacity.

  6. Mexico City's active photochemistry: conclusions from the MCMA-2003 study

    NASA Astrophysics Data System (ADS)

    Brune, W.; Shirley, T.; Lesher, R.; Mao, J.; Volkamer, R.; Molina, L.; Molina, M.; Velasco, E.; Westberg, H.; Lamb, B.; Jobson, T.; Alexander, M.; Gonzalez, B. C.

    2004-12-01

    Mexico City Metropolitan Area's active photochemistry was studied using an extensive suite of measurements on the CENICA environmental laboratory's roof, as part of the MCMA-2003 field study. Intense morning sunlight photolyzed HONO and HCHO, producing hydrogen oxides (OH and HO2) at high rates. The HOx interacted with rush-hour volatile organic compounds (VOCs) and nitrogen oxides (NOx), amplifying the production rate of ozone and nitric acid. With typically 100 ppbv of NOx and 1 ppmC of VOCs, ozone production rates exceeded 30 ppbv/hour, routinely creating in excess of 150 ppbv of ozone, even though the midday mixed layer was more than 3 km deep. Analyses of glyoxal, a product of VOC oxidation, and the hydroperoxyl radical (HO2) indicate that MCMA's ozone production was VOC-limited during morning rush hour, when typically 1/2 of the ozone is produced, and for a significant number of days during midday and afternoon at the site. Aspects of Mexico City's active photochemistry will be compared to the observed photochemistry in U.S. urban areas.

  7. 33 CFR 334.763 - Naval Support Activity Panama City; Gulf of Mexico; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Naval Support Activity Panama City; Gulf of Mexico; restricted area. 334.763 Section 334.763 Navigation and Navigable Waters CORPS OF....763 Naval Support Activity Panama City; Gulf of Mexico; restricted area. (a) The area. The area is...

  8. 33 CFR 334.763 - Naval Support Activity Panama City; Gulf of Mexico; restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Naval Support Activity Panama City; Gulf of Mexico; restricted area. 334.763 Section 334.763 Navigation and Navigable Waters CORPS OF....763 Naval Support Activity Panama City; Gulf of Mexico; restricted area. (a) The area. The area is...

  9. Model assessing the impact of biomass burning on air quality and photochemistry in Mexico City

    Treesearch

    W. Lei; G. Li; C. Wiedinmyer; R. J. Yokelson; L. T. Molina

    2010-01-01

    Biomass burning is a major global emission source for trace gases and particulates. Various multi-platform measurements during the Mexico City Metropolitan Area (MCMA)-2003 and Megacity Initiative: Local and Global Research Observations (MILAGRO)-2006 campaigns suggest significant influences of biomass burning (BB) on air quality in Mexico City during the dry season,...

  10. Challenges and Opportunities of Air Quality Management in Mexico City

    NASA Astrophysics Data System (ADS)

    Paramo, V.

    2013-05-01

    The Mexico City Metropolitan Area (MCMA) is located in the central plateau of Mexico and is the capital of the country. Its natural characteristics present favorable conditions for air pollution formation and accumulation: mountains surrounding the city, frequent thermal inversions, high isolation all around the year and weak winds. To these natural conditions, a population of more than 20 million inhabitants, a fleet of 4.5 million vehicles and more than 4 thousands industries, make air quality management a real challenge for governments of the region. Intensive air quality improvement actions and programs began at the end of the 1980's and continued nowadays. Since then criteria air pollutants concentrations have decreased in such a way that currently most of pollutants meet the Mexican air quality standards, except for ozone and particulate matter. Applied measures comprised of fuel quality improvements, fuel replacements, regulations for combustion processes, closing of high polluting refineries and industries, regulations of emissions for new and on road vehicles, mandatory I/M programs for vehicles, circulation restrictions for vehicles (Day without car program), alert program for elevated air pollution episodes, improvement of public transportation, among others. Recent researches (MILAGRO 2006 campaign) found that currently it is necessary to implement emissions reduction actions for Volatile Organic Compounds, particulate matter with a diameter of less than 2.5 micrometers PM2.5 and Nitrogen Oxides, in order to reduce concentrations of ozone and fine particulate matter. Among the new measures to be implemented are: regulations for VOCs emissions in the industry and commercial sectors; regulation of the diesel fleet that includes fleets renewal, filters and particulate traps for in use vehicles and regulation of the cargo fleet; new schemes for reducing the number of vehicles circulating in the city; implementation of non-motorized mobility programs; among

  11. Psychosocial needs of young breast cancer survivors in Mexico City, Mexico.

    PubMed

    Hubbeling, Harper G; Rosenberg, Shoshana M; González-Robledo, Maria Cecilia; Cohn, Julia G; Villarreal-Garza, Cynthia; Partridge, Ann H; Knaul, Felicia M

    2018-01-01

    Young breast cancer survivors in Mexico face distinct psychosocial challenges that have not been characterized. This study aims to describe the psychosocial needs of young breast cancer survivors in Mexico at 5 or more years of survivorship, identifying areas of focus for early interventions. Breast cancer patients diagnosed at age 40 or prior with 5 or more years since diagnosis were invited to participate in one-on-one 30-60 minute semi-structured audio-recorded interviews at the Instituto Nacional de Cancerología in Mexico City. Transcripts were coded using thematic analysis with NVivo software. 25 women participated. Five major phenomena emerged from analysis: (1) minimization of fertility concerns; (2) persistence of body image disturbance over time; (3) barriers to employment during survivorship; (4) impact on family relationships and social networks; & (5) unmet psychological care and informational needs. Early interventions with a focus on fertility loss education, access to reconstructive surgery and body image support, guidance during return-to-work, assistance with childcare, integration of psychological care and the fulfillment of informational needs could ameliorate long-term psychological and social distress for young breast cancer survivors in Mexico.

  12. Psychosocial needs of young breast cancer survivors in Mexico City, Mexico

    PubMed Central

    Rosenberg, Shoshana M.; González-Robledo, Maria Cecilia; Cohn, Julia G.; Villarreal-Garza, Cynthia; Partridge, Ann H.; Knaul, Felicia M.

    2018-01-01

    Objective Young breast cancer survivors in Mexico face distinct psychosocial challenges that have not been characterized. This study aims to describe the psychosocial needs of young breast cancer survivors in Mexico at 5 or more years of survivorship, identifying areas of focus for early interventions. Methods Breast cancer patients diagnosed at age 40 or prior with 5 or more years since diagnosis were invited to participate in one-on-one 30–60 minute semi-structured audio-recorded interviews at the Instituto Nacional de Cancerología in Mexico City. Transcripts were coded using thematic analysis with NVivo software. Results 25 women participated. Five major phenomena emerged from analysis: (1) minimization of fertility concerns; (2) persistence of body image disturbance over time; (3) barriers to employment during survivorship; (4) impact on family relationships and social networks; & (5) unmet psychological care and informational needs. Conclusions Early interventions with a focus on fertility loss education, access to reconstructive surgery and body image support, guidance during return-to-work, assistance with childcare, integration of psychological care and the fulfillment of informational needs could ameliorate long-term psychological and social distress for young breast cancer survivors in Mexico. PMID:29787612

  13. Urban-Rural Humidity Contrasts in Mexico City

    NASA Astrophysics Data System (ADS)

    Jáuregui, E.; Tejeda, A.

    1997-02-01

    Data from one pair of urban-suburban (Tacubaya and Airport) andone pair of urban-rural (School of Mines and Plan Texcoco) temperature and humidity measuring stations were used to illustrate specific humidity(q) contrasts in Mexico City. Results show a marked seasonal variation of q from around 7.9 g kg-1 during the dry months to 10 g kg-1 in the wet season (May-October) on both urban and suburban sites. The mean monthly contrasts for this pair of stations, albeit small, show that the city air is somewhat drier during the first half of the year. Comparison of urban and rural q on an hourly basis shows that although urban air is more humid at night the reverse is true during the afternoon. Areal distribution of q shows two centres of maximum humidity over the city at night and a corresponding minimum during the afternoon. On average the urban-rural contrasts in q were found to be somewhat smaller than the estimated uncertainty. The above results are in agreement with mid-latitude experience.

  14. The first massive astronomical observation event in Mexico City

    NASA Astrophysics Data System (ADS)

    Espinosa, Mariana; Hernandez, Xavier

    2011-06-01

    On the night of the 20th of February 2008 there was a total eclipse of the moon visible from Mexico City, with a total duration from 19:42 hrs to 23:09 hrs. At the Instituto de Astronomía, UNAM, we took this opportunity to organise a massive astronomical party on the central plaza of the city, the Zocalo. Over a period of about 6 hrs. we set up a huge astro-party, with free use of over 100 telescopes, where we estimate over 40,000 persons looked through an astronomical telescope at the moon and Saturn, most for the first time in their lives. Numerous stands including a children's games, an Astronomy conference room, and the free distribution of Astronomical material were organised. Here we describe some of the issues associated with the planning and implementation of the event. Coordination issues were complex, involving interaction with divers and numerous authorities, city, national, police, traffic, medical assistance in readiness, aide from other universities, and amateur astronomical societies, which supplied most of the telescopes. An extensive publicity campaign was launched with several weeks of anticipation, and although we had no way of estimating the public response, we were ready with over 800 volunteers at the Zócalo on the 20th of February. The public response was massive and overwhelmingly positive, thousands swarmed the square in a completely peaceful and well organised interaction between Astronomy and society at large, over many complementary levels

  15. In-situ monitoring of deformation of clayey and volcanic sequences in the lacustrine plain of Iztapalapa, Mexico City

    NASA Astrophysics Data System (ADS)

    Carreon-Freyre, D.; Cerca, M.; Barrientos, B.; Gutierrez, R.; Blancas, D.

    2012-12-01

    Major cities of Central Mexico with lowering of land elevation problems are located in inter-volcanic and fault bounded basins within the central Trans-Mexican Volcanic Belt (TMVB). The most representative and studied case of ground deformation is Mexico City, where the Iztapalapa Municipality presents the highest population density. This area is located over the geological contact between the "Sierra de Santa Catarina" volcanic range and a lacustrine plain. Filling of lacustrine basins includes silty and clayey sediments as well as pyroclastic deposits (coarse and fine grained) and volcanic rocks layers. We used Ground Penetrating Radar (GPR) and MASW prospection to evaluate contrasts in the physical properties of fine grained soils and identify geometry of the deformational features and implemented a mechanical system for in situ monitoring in fractured sites. Deformational features in this basin reflect an interplay between the geological history (depositional conditions), load history, seismic activity, and faulting. Plastic mechanical behaviour predominates in these clayey sediments and differential deformation locally triggers brittle fracturing and/or subsidence of the surface. In this work we present the results of monitoring and characterization of ground deformation and fracturing in different sequences, our results show a dynamic interplay between the mechanisms of ground fracturing and the stress history of sedimentary sequences. Relating the mechanical behaviour of the studied sequences with variations of physical and geological properties should be taken into account to estimate land level lowering and risk of fracturing for urban development planning.

  16. [Sociodemographic context of homicide in Mexico City: a spatial analysis].

    PubMed

    Fuentes Flores, César; Sánchez Salinas, Omar

    2015-12-01

    Investigate the spatial distribution pattern of the homicide rate and its relation to sociodemographic features in the Benito Juárez, Coyoacán, and Cuauhtémoc districts of Mexico City in 2010. Inferential cross-sectional study that uses spatial analysis methods to study the spatial association of the homicide rate and demographic features. Spatial association was determined through the location quotient, multiple regression analysis, and the use of geographically weighted regression. Homicides show a heterogeneous location pattern with high rates in areas with non-residential land use, low population density, and low marginalization. Spatial analysis tools are powerful instruments for the design of prevention- and recreation-focused public safety policies that aim to reduce mortality from external causes such as homicides.

  17. Organochlorine pesticides residues in bottled drinking water from Mexico City.

    PubMed

    Díaz, Gilberto; Ortiz, Rutilio; Schettino, Beatriz; Vega, Salvador; Gutiérrez, Rey

    2009-06-01

    This work describes concentrations of organochlorine pesticides in bottled drinking water (BDW) in Mexico City. The results of 36 samples (1.5 and 19 L presentations, 18 samples, respectively) showed the presence of seven pesticides (HCH isomers, heptachlor, aldrin, and p,p'-DDE) in bottled water compared with the drinking water standards set by NOM-127-SSA1-1994, EPA, and World Health Organization. The concentrations of the majority of organochlorine pesticides were within drinking water standards (0.01 ng/mL) except for beta-HCH of BW 3, 5, and 6 samples with values of 0.121, 0.136, and 0.192 ng/mL, respectively. It is important monitoring drinking bottled water for protecting human health.

  18. [Partner violence against pregnant women in Mexico City].

    PubMed

    Doubova Dubova, Svetlana Vladislavovna; Pámanes-González, Verónica; Billings, Deborah L; Torres-Arreola, Laura del Pilar

    2007-08-01

    To assess factors related to partner violence against pregnant women. Data were collected from 383 pregnant women eligible attending five family medicine units of the Mexican institute of social security in Mexico City, Mexico, between September 2003 and August 2004. Data collection was carried out using a questionnaire developed for the study. Of all women interviewed, 120 (31.1%) reported that they had been exposed to psychological and/or physical and/or sexual violence perpetrated by their partners during the current pregnancy; 10% reported combined violence and 21% isolated violence. Psychological violence was most frequently reported (in 93% of the "experienced violence" group). As for their perception of violence there was not found any significant differences between those women who had experienced versus those who did not experience violence. Only about 20% of women had knowledge of centers for women victims of violence. The factors significantly associated with partner violence among pregnant women included: being single (OR=3.02; 95% CI: 1.17;7.83), being unmarried and living with a partner (OR=2.22; 95% CI: 1.11;4.42), history of violence during childhood (OR= 3.08; 95% CI: 1.62;5.85), alcohol consumption by the partner (OR=1.87; 95% CI: 1.02;3.42) and emotional distress among women (OR=4.17; 95% CI: 1.12;15.51). The study results stress other research findings that violence against pregnant Mexican women is still common.

  19. Learning from the Mexico City Earthquake in 1985

    NASA Astrophysics Data System (ADS)

    Santos-Reyes, Jaime; Alvarado-Corona, Rafael

    2010-05-01

    Natural disasters are increasing alarmingly worldwide in recent years. They have killed millions of people, and adversely affected the life of at least one billion people. Given this, natural disasters present a great challenge to society today concerning how they are to be mitigated so as to produce an acceptable risk is a question which has come to the fore in dramatic ways recently. The paper addresses the following question: what could be learnt from natural disasters? The paper presents some preliminary results of the analysis of the Mexico City earthquake in 1985, by applying the Management Oversight Risk Tree (MORT) model. On September 19, 1985, at 7:19 hrs local time an intense earthquake with a magnitude of 8.1 on the Richter scale struck the country. The epicentre was located near the coast of the state of Guerrero, about 400 kilometres southeast of Mexico City. It is believed that thousands of people were affected and more than 10000 people were killed by the earthquake. On the other hand, the MORT model may be regarded as a structured checklist in the form of a complex ‘fault-tree' model that is intended to ensure that all aspects of an organization's management are looked into when assessing the possible causes of an incident. Moreover, the MORT has been applied extensively to the analysis of past failure of socio-technical systems; this is the first time that it has been applied to the case of natural disasters. A number of organizational failures have been highlighted by the model. It is hoped that by conducting such analysis lessons can be learnt and disseminated so that the impact of natural disasters such as Earthquakes can be mitigated in the future.

  20. Fine particle receptor modeling in the atmosphere of Mexico City.

    PubMed

    Vega, Elizabeth; Lowenthal, Douglas; Ruiz, Hugo; Reyes, Elizabeth; Watson, John G; Chow, Judith C; Viana, Mar; Querol, Xavier; Alastuey, Andrés

    2009-12-01

    Source apportionment analyses were carried out by means of receptor modeling techniques to determine the contribution of major fine particulate matter (PM2.5) sources found at six sites in Mexico City. Thirty-six source profiles were determined within Mexico City to establish the fingerprints of particulate matter sources. Additionally, the profiles under the same source category were averaged using cluster analysis and the fingerprints of 10 sources were included. Before application of the chemical mass balance (CMB), several tests were carried out to determine the best combination of source profiles and species used for the fitting. CMB results showed significant spatial variations in source contributions among the six sites that are influenced by local soil types and land use. On average, 24-hr PM2.5 concentrations were dominated by mobile source emissions (45%), followed by secondary inorganic aerosols (16%) and geological material (17%). Industrial emissions representing oil combustion and incineration contributed less than 5%, and their contribution was higher at the industrial areas of Tlalnepantla (11%) and Xalostoc (8%). Other sources such as cooking, biomass burning, and oil fuel combustion were identified at lower levels. A second receptor model (principal component analysis, [PCA]) was subsequently applied to three of the monitoring sites for comparison purposes. Although differences were obtained between source contributions, results evidence the advantages of the combined use of different receptor modeling techniques for source apportionment, given the complementary nature of their results. Further research is needed in this direction to reach a better agreement between the estimated source contributions to the particulate matter mass.

  1. [Social representation of AIDS among students of Mexico City].

    PubMed

    Flores-Palacios, Fátima; Leyva-Flores, René

    2003-01-01

    To analyze the social representation of AIDS in a group of high school students aged 16 to 23 years in Mexico City. A non-probabilistic, cross-sectional research was carried out in a public high school in Mexico City. Students of all grades were invited to participate in the study, which took place between 1999 and 2000. Forty-six students participated; 28% male and 72% female. This exploratory field study consisted of three phases, each to address one of three dimensions: cognitive using free association techniques, representational field using semi-structured interviews; and context attitude by means of two discussion groups. In the latter, the information was previously collected for discussion. The cognitive nucleus on AIDS included the association between sex, disease, and death. The representational field of AIDS is constructed around the transmission-prevention unit. Construct elements are virus, contagion, sex, protection, and condom. An ambivalent attitude was identified towards HIV prevention and transmission: "We are only half responsible". Situations such as "rape, blood transfusions, infected syringes" were prominent in the discussion group, deemed beyond their control to prevent transmission, thus explaining the group's ambivalent attitude towards prevention. The usefulness of condoms was associated with prevention of pregnancy rather than with prevention of sexually transmitted infections. The social representation of HIV/AIDS in young students conforms a multidimensional corpus where different elements of scientific order and common sense converge and interact, such as beliefs, myths, taboos, and fears. All of these contribute to construct the meaning of AIDS. The English version of this paper is available at:http://www.insp.mx/salud/index.html.

  2. Decriminalization of abortion in Mexico City: the effects on women's reproductive rights.

    PubMed

    Becker, Davida; Díaz Olavarrieta, Claudia

    2013-04-01

    In April 2007, the Mexico City, Mexico, legislature passed landmark legislation decriminalizing elective abortion in the first 12 weeks of pregnancy. In Mexico City, safe abortion services are now available to women through the Mexico City Ministry of Health's free public sector legal abortion program and in the private sector, and more than 89 000 legal abortions have been performed. By contrast, abortion has continued to be restricted across the Mexican states (each state makes its own abortion laws), and there has been an antichoice backlash against the legislation in 16 states. Mexico City's abortion legislation is an important first step in improving reproductive rights, but unsafe abortions will only be eliminated if similar abortion legislation is adopted across the entire country.

  3. Bacteriological quality of crops irrigated with wastewater in the Xochimilco plots, Mexico City, Mexico.

    PubMed

    Rosas, I; Báez, A; Coutiño, M

    1984-05-01

    Xochimilco county plots (Mexico City), one of the most fertile agricultural areas in the Valley of Mexico, produce a large portion of the fresh vegetables consumed in the city. These plots are generally irrigated with domestic wastewater, and for this reason, it was deemed important to examine and evaluate the bacteriological quality of the water, soil, and vegetables from these plots that are harvested and marketed. The soils were also examined for the classical parameters such as nitrates, ammonia, etc., and organic matter and texture. The crops selected for this study were radishes, spinach, lettuce, parsley, and celery because they are usually consumed raw. The highest bacterial counts were encountered in leafy vegetables, i.e., spinach (8,700 for total coliform and 2,400 for fecal coliform) and lettuce (37,000 for total coliform and 3,600 for fecal coliform). Statistically significant differences in bacterial counts between rinsed and unrinsed edible portions of the crops were observed even in rinsed vegetables, and high densities of fecal coliform were detected, indicating that their consumption represents a potential health hazard. The total coliform values found in irrigation water ranged from 4 X 10(4) to 29 X 10(4), and for fecal coliform the values ranged from 5 X 10(2) to 30 X 10(2).

  4. Bacteriological quality of crops irrigated with wastewater in the Xochimilco plots, Mexico City, Mexico.

    PubMed Central

    Rosas, I; Báez, A; Coutiño, M

    1984-01-01

    Xochimilco county plots (Mexico City), one of the most fertile agricultural areas in the Valley of Mexico, produce a large portion of the fresh vegetables consumed in the city. These plots are generally irrigated with domestic wastewater, and for this reason, it was deemed important to examine and evaluate the bacteriological quality of the water, soil, and vegetables from these plots that are harvested and marketed. The soils were also examined for the classical parameters such as nitrates, ammonia, etc., and organic matter and texture. The crops selected for this study were radishes, spinach, lettuce, parsley, and celery because they are usually consumed raw. The highest bacterial counts were encountered in leafy vegetables, i.e., spinach (8,700 for total coliform and 2,400 for fecal coliform) and lettuce (37,000 for total coliform and 3,600 for fecal coliform). Statistically significant differences in bacterial counts between rinsed and unrinsed edible portions of the crops were observed even in rinsed vegetables, and high densities of fecal coliform were detected, indicating that their consumption represents a potential health hazard. The total coliform values found in irrigation water ranged from 4 X 10(4) to 29 X 10(4), and for fecal coliform the values ranged from 5 X 10(2) to 30 X 10(2). PMID:6742825

  5. Volatile organic compounds in the atmosphere of Mexico City

    NASA Astrophysics Data System (ADS)

    Garzón, Jessica P.; Huertas, José I.; Magaña, Miguel; Huertas, María E.; Cárdenas, Beatriz; Watanabe, Takuro; Maeda, Tsuneaki; Wakamatsu, Shinji; Blanco, Salvador

    2015-10-01

    The Mexico City Metropolitan Area (MCMA) is one of the most polluted megacities in North America. Therefore, it is an excellent benchmark city to understand atmospheric chemistry and to implement pilot countermeasures. Air quality in the MCMA is not within acceptable levels, mainly due to high ground levels of ozone (O3). Tropospheric O3 is a secondary pollutant formed from the oxidation of volatile organic compounds (VOCs) in the presence of nitrogen oxides and sunlight. To gain a better understanding of O3 formation in megacities, evaluate the effectiveness of already-implemented countermeasures, and identify new cost-effective alternatives to reduce tropospheric O3 concentrations, researchers and environmental authorities require updated concentrations for a broader range of VOCs. Moreover, in an effort to protect human health and the environment, it is important to understand which VOCs exceed reference safe values or most contribute to O3 formation, as well as to identify the most probable emission sources of those VOCs. In this work, 64 VOCs, including 36 toxic VOCs, were measured at four sites in the MCMA during 2011-2012. VOCs related to liquefied petroleum gas leakages exhibited the highest concentrations. Toxic VOCs with the highest average concentrations were acetone and ethanol. The toxic VOC benzene represented the highest risk to Mexican citizens, and toluene contributed the most to O3 formation. Correlation analysis indicated that the measured VOCs come from vehicular emissions and solvent-related industrial sources.

  6. Decriminalization of Abortion in Mexico City: The Effects on Women’s Reproductive Rights

    PubMed Central

    Díaz Olavarrieta, Claudia

    2013-01-01

    In April 2007, the Mexico City, Mexico, legislature passed landmark legislation decriminalizing elective abortion in the first 12 weeks of pregnancy. In Mexico City, safe abortion services are now available to women through the Mexico City Ministry of Health’s free public sector legal abortion program and in the private sector, and more than 89 000 legal abortions have been performed. By contrast, abortion has continued to be restricted across the Mexican states (each state makes its own abortion laws), and there has been an antichoice backlash against the legislation in 16 states. Mexico City’s abortion legislation is an important first step in improving reproductive rights, but unsafe abortions will only be eliminated if similar abortion legislation is adopted across the entire country. PMID:23409907

  7. [Family planning in a suburban development of Mexico City].

    PubMed

    Gutiérrez Avila, J H; González Cortés, A; González Cortés, A

    1982-01-01

    To study the prevalence of contraceptive use among women in reproductive age, 15-50, and living in urban slums, the female population of Colonia Ajusco was surveyed. Colonia Ajusco is situated south of Mexico City; 70% of its population comes from the interior of the country; there is no drinkable water and no sewage system; housing conditions and urban services are very poor. 606 women were investigated; 58% of them were below age 36, and 53.5% were parity 4 and over. 56.4% used contraception; of these 36.7% used the IUD, 23.1% the pill, and 16.7% had been sterilized. The contraceptive method used seemed to be strictly related to the type of medical services used; women using the IUD were mostly patients of the Social Security medical services, while women using the pill were mostly clients of private physicians. There was no association between age and the method used. 88.4% of women not using contraception did not have easy availability of medical services. The percentage of women using contraception, 56.4% seems high in relation to other Latin American countries, but it is very low in relation to the percentage of contraceptive users in more developed countries (93% in England). The use of the IUD as the method of choice can be explained by several factors: the massive national advertising campaign, low cost, ease of insertion, and no need for sustained motivation to use contraception. From all studies on contraceptive prevalence in Mexico it appears that women start to regulate their fertility after the 1st child, or even after the 4th child. Women below 20 still tend to resort to illegal abortion.

  8. Physiological effects of the Mexico City atmosphere on lichen transplants on oaks

    SciTech Connect

    Zambrano, A.; Nash, T.H. III; Gries, C.

    1999-10-01

    Two lichen species, Usnea ceratina Ach. and Everniastrum neocirrhatum (Hale M. Wirth) Hale ex Sipman, were transplanted for 54 d into an oak forest (Quercus rugosa) in the vicinity of Mexico City to assess their ability to survive near a highly polluted urban environment. Net photosynthesis based on dry weight and chlorophyll b decreased respectively ca. 30 and 25% compared with control samples in a less polluted site, ca. 100 km north of Mexico City. There was no interspecific difference in the response of carbon fixation, but E. neocirrhatum was more sensitive to chlorophyll b degradation near Mexico City thanmore » U. ceratina. Chlorophyll a was also degradated (ca. 15%) near Mexico City. Changes in total carotenes were mostly dependent on species and time rather than on location. High concurrent levels of ozone and sulfur dioxide in the air are discussed as possible causes of the decline in the lichen photosynthesis and chlorophyll content.« less

  9. Exploding cities: housing the masses in Paris, Chicago, and Mexico City, 1850-2000.

    PubMed

    Platt, Harold L

    2010-01-01

    In The Mystery of Capitalism , the darling of neoliberalism, Hernando de Soto posits that secure property titles explain “why capitalism triumphs in the West and fails everywhere else.” While social scientists have taken him to task for an oversimplification of the causes and remedies of poverty, historians have contributed little to this important policy debate. Applying comparative methods across time and space, such a retrospective analysis exposes serious flaws in de Soto’s thesis. Case studies of Paris, Chicago, and Mexico City covering successive, fifty-year periods support his contention that property law was the single most important factor in determining the fate of rural migrants trying to find a place to live in these exploding cities. But in each case, residential property played a far more complex role in creating the social and physical geography of the city than its simple exchange value. This article illuminates some of these alternative economic uses and embedded cultural meanings of identities of place. It also shows how urban growth machines create capital value in property for some by creating environmental injustice of substandard conditions of everyday life for others.

  10. Urban structure analysis of mega city Mexico City using multisensoral remote sensing data

    NASA Astrophysics Data System (ADS)

    Taubenböck, H.; Esch, T.; Wurm, M.; Thiel, M.; Ullmann, T.; Roth, A.; Schmidt, M.; Mehl, H.; Dech, S.

    2008-10-01

    Mega city Mexico City is ranked the third largest urban agglomeration to date around the globe. The large extension as well as dynamic urban transformation and sprawl processes lead to a lack of up-to-date and area-wide data and information to measure, monitor, and understand the urban situation. This paper focuses on the capabilities of multisensoral remotely sensed data to provide a broad range of products derived from one scientific field - remote sensing - to support urban managing and planning. Therefore optical data sets from the Landsat and Quickbird sensors as well as radar data from the Shuttle Radar Topography Mission (SRTM) and the TerraSAR-X sensor are utilised. Using the multi-sensoral data sets the analysis are scale-dependent. On the one hand change detection on city level utilising the derived urban footprints enables to monitor and to assess spatiotemporal urban transformation, areal dimension of urban sprawl, its direction, and the built-up density distribution over time. On the other hand, structural characteristics of an urban landscape - the alignment and types of buildings, streets and open spaces - provide insight in the very detailed physical pattern of urban morphology on higher scale. The results show high accuracies of the derived multi-scale products. The multi-scale analysis allows quantifying urban processes and thus leading to an assessment and interpretation of urban trends.

  11. Abusive Head Trauma at a Tertiary Care Children's Hospital in Mexico City. A Preliminary Study

    ERIC Educational Resources Information Center

    Diaz-Olavarrieta, Claudia; Garcia-Pina, Corina A.; Loredo-Abdala, Arturo; Paz, Francisco; Garcia, Sandra G.; Schilmann, Astrid

    2011-01-01

    Objectives: Determine the prevalence, clinical signs and symptoms, and demographic and family characteristics of children attending a tertiary care hospital in Mexico City, Mexico, to illustrate the characteristics of abusive head trauma among this population. Methods: This is a cross-sectional descriptive study of infants and children under 5,…

  12. UV-B Measurements in Mexico City: Comparison with Modeled UVB and Black Carbon

    NASA Astrophysics Data System (ADS)

    Marley, N. A.; Gaffney, J. S.; Frederick, J. E.

    2004-12-01

    Ultraviolet-B radiation (UV-B) represents a chemically important region of the sun's spectrum. At the earth's surface, UV-B can initiate a number of important photochemical reactions (e.g., ozone photolysis) that lead to the formation of OH radicals. Where levels of nitrogen oxides are high and reactive hydrocarbons are found, as in Mexico City and other megacities, UV-B can initiate photochemical smog formation. We used a broadband instrument to obtain UV-B measurements in Mexico City during the Mexico City Metropolitan Area 2003/Mexico City Megacity 2003 field study. We then used a simple radiation model for the Mexico City latitude, altitude, and time of year to construct UV-B contours for comparison with our results. Early morning discrepancies involve reductions in UV-B that are consistent with the presence of significant levels of BC in the Mexico City environment. During most afternoons, UV-B reductions were dominated by clouds. The results are discussed in terms of the potential impacts of BC on UV-B and downwind photochemical processes. The authors wish to thank the researchers at Centro Nacional de Investigación en Calidad Ambiental (CENICA), Mexico City. This work was supported by the U.S. Department of Energy, Atmospheric Science Program (Marley and Gaffney), and the U.S. Environmental Protection Agency (Frederick). We also wish to acknowledge Drs. Mario and Luisa Molina for their help in organizing and directing the Mexico City Metropolitan Area 2003 field study, during which these data were collected.

  13. Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

    SciTech Connect

    Avila-Olivera, Jorge A.; Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, C.U., 58030 Morelia, Michoacan; Farina, Paolo

    2008-05-07

    In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults 'Oriente' and 'Poniente'. At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system 'Taxco-San Miguel de Allende'. In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create amore » map of the current phreatic level decline in city with the information of deep wells and using the 'kriging' method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults 'Oriente' and 'Universidad Pedagogica' are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year.« less

  14. Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

    NASA Astrophysics Data System (ADS)

    Avila-Olivera, Jorge A.; Farina, Paolo; Garduño-Monroy, Victor H.

    2008-05-01

    In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults "Oriente" and "Poniente". At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system "Taxco-San Miguel de Allende". In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create a map of the current phreatic level decline in city with the information of deep wells and using the "kriging" method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults "Oriente" and "Universidad Pedagógica" are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year.

  15. Seroprevalence of Toxoplasma gondii infection in captive mammals in three zoos in Mexico City, Mexico.

    PubMed

    Alvarado-Esquivel, Cosme; Gayosso-Dominguez, Edgar Arturo; Villena, Isabelle; Dubey, J P

    2013-09-01

    Antibodies to Toxoplasma gondii were determined in 167 mammals in three zoos in Mexico City, Mexico, using the modified agglutination test (MAT). Overall, antibodies to T. gondii were found in 89 (53.3%) of the 167 animals tested. Antibodies were found in 35 of 43 wild Felidae: 2 of 2 bobcats (Lynx rufus); 4 of 4 cougars (Puma concolor); 10 of 13 jaguars (Panthera onca); 5 of 5 leopards (Panthera pardus); 7 of 7 lions (Panthera leo); 2 of 3 tigers (Panthera tigris); 2 of 3 ocelots (Leopardus pardalis); 2 of 2 Sumatran tigers (Panthera tigris sumatrae); lof 2 Jaguarundi (Herpailurus jagouaroundi); but not in 0 of 2 oncillas (Leopardus tigrinus). Such high seroprevalence in wild felids is of public health significance because of the potential of oocyst shedding. Four of 6 New World primates (2 of 2 Geoffroy's spider monkeys [Ateles geoffroyi], 1 of 3 Patas monkeys [Erythrocebus patas], and 1 of 1 white-headed capuchin [Cebus capucinus]) had high MAT titers of 3,200, suggesting recently acquired infection; these animals are highly susceptible to clinical toxoplasmosis. However, none of these animals were ill. Seropositivity to T. gondii was found for the first time in a number of species.

  16. Fluoride content in bottled waters, juices and carbonated soft drinks in Mexico City, Mexico.

    PubMed

    Jimenez-Farfan, M D; Hernandez-Guerrero, J C; Loyola-Rodriguez, J P; Ledesma-Montes, C

    2004-07-01

    The objective of this study was to analyse 283 samples of soft drinks available in the metropolitan market of Mexico City, Mexico: 105 juices, 101 nectars, 57 carbonated drinks and 20 bottled waters. Samples of the beverages were analysed using an Orion 720A potentiometer and an Orion 9609BN F ion-specific electrode. Fluoride concentration in the above-mentioned products ranged from 0.07 to 1.42 p.p.m. It was found that fluoride concentrations varied according to the brand, flavour and presentation of the product. The highest mean concentration of fluoride was found in the juices and cola drinks (0.67 +/- 0.38 and 0.49 +/- 0.41 p.p.m., respectively). The mean fluoride concentration for carbonated drinks was 0.43 +/- 0.36 p.p.m. Bottled waters had a fluoride concentration of 0.21 +/- 0.08 p.p.m. The findings suggest that fluoride ingested through bottled drinks represents an important part of the total fluoride ingested by the population. In view of the wide variation of fluoride concentration in the tested products, it is necessary to implement regulatory guidelines for controlling its concentration in order to prevent dental fluorosis.

  17. Service use among Mexico City adolescents with suicidality

    PubMed Central

    Borges, Guilherme; Benjet, Corina; Medina-Mora, Maria Elena; Orozco, Ricardo; Familiar, Itziar; Nock, Matthew K.; Wang, Philip S.

    2009-01-01

    Background We report the lifetime and 12-month prevalence and associations of mental health treatment among Mexican adolescents with suicide-related outcomes (SROs; including ideation, plans, gestures and attempts). Methods A representative multistage probability household survey of 3005 adolescents aged 12 to 17 years residing in the Mexico City Metropolitan Area was carried out in 2005. Discrete time survival analyses were used to assess the relationships between SROs and receiving treatment for emotional, alcohol, or drug problems. Results The prevalence of lifetime service use among respondents with SROs was 35% for those with ideation only, 44% for those with ideation and plan, 49% for those with gesture and 50% for those with attempt; the prevalence of 12-month service use was 10%, 24%, 6% and 21%, respectively. Timing between onset of SRO and receiving treatment for emotional, alcohol, or drug problems showed that about 50% of adolescents will have contact with a service provider before developing any SRO. Healthcare professionals were the most likely to be consulted, followed by school-based programs. Limitations This survey was limited to adolescents living in one of the largest metropolitan areas in the world and the analyses used data on retrospectively reported ages of onset that are subject to recall errors. Conclusions Most suicidal adolescents do not receive treatment, and many adolescents develop their suicidality in spite of prior contacts with service providers. Interventions to increase treatment, prevention, and monitoring are sorely needed for this vulnerable population. PMID:19411113

  18. Mutagenicity assessment of airborne particles in Mexico City

    NASA Astrophysics Data System (ADS)

    Villalobos-Pietrini, Rafael; Blanco, Salvador; Gomez-Arroyo, Sandra

    The Ames's TA98 strain of Salmonella typhimurium with and without mammalian metabolic activation was used to detect the mutagenic activity of organic chemicals associated with airborne particles. Two kinds of particles: total suspended (TSP) and those particles with an aerodynamic diameter of 10 μm or smaller (PM 10) were collected in glass fiber filters using high-volume samplers during the dry season (December 1989-March 1990) in the Metropolitan Area of Mexico City at five stations of the air quality network belonging to the Ministry of Social Development. Although the highest mass concentrations of particles were obtained from the Northeastern and Southeastern areas, the largest frequency of mutations was found Downtown which indicated that vehicle exhaust was an important source. Contrary to what was expected, the mutagenic responses were higher for PM10 than for TSP samples. On the other hand, the microsome activation increased significantly the mutagenic activity of the complex mixture, which hinted at the presence of higher amounts of indirect (or promutagens) than direct mutagens both for TSP and PM10.

  19. Reformulated gasolines: The experience of Mexico City Metropolitan Zone

    SciTech Connect

    Alvarez, H.B.; Jardon, R.T.; Echeverria, R.S.

    1997-12-31

    The introduction of several reformulated gasolines into the Mexico City Metropolitan Zone (MCMZ) in the middle 1986 is an example of using fuel composition to improve, in theory, the air quality. However, although these changes have resulted in an important reduction of lead airborne concentrations, a worsened situation has been created. Ozone levels in the atmosphere MCMZ have presented a sudden rise since the introduction of the first reformulated gasoline, reaching in the 1990`s an annual average of 1,700 exceedances to the Mexican Ozone Air Quality Standard (0.11 ppm not to be exceeded 1 hr. a day one day amore » year). The authors examine the tendency on ozone air quality in MCMZ in relation with the changes in gasoline composition since 1986. The authors also discuss the importance to perform an air quality impact analysis before the introduction of reformulated gasolines in countries where the local economy do not allow to change the old car fleet not fitted with exhaust treatment devices.« less

  20. Photochemistry in the Atmospheres of Denver and Mexico City

    NASA Astrophysics Data System (ADS)

    Cantrell, C. A.

    2016-12-01

    The composition of atmospheres in and downwind of urban centers has been the subject of study for decades. While early campaigns involved measurements exclusively from the ground, more recent studies have included airborne-based observations. Improved understanding has hinged critically on the development of instrumentation for better qualitifcation of pollutants, and measurement of previously unobserved species in the gas and particulate phases. Comprehensive, well-planned studies have, over time, led to more detailed understanding of chemical transformations and thus improved model representations and directions for further research. This presentation focuses on findings from two case studies of urban atmospheres, namely the MILAGRO study in the Mexico City metropolitan area and the FRAPPE study in the Denver metropolitan region. Both studies made use of extensive ground-based networks and multiple aircraft platforms. The data collected during these studies have been combined with numerical models to derive assessments of the evolution of atmospheric composition due to photochemistry, mixing, and surface processes. Here, analysis of MILAGRO data focuses on the evolution of outflow downwind of the urban region. In FRAPPE, the focus is the possible role of oil and gas exploration on urban air quality. These findings are used to assess the accuracy of current numerical models to reproduce observations, and to point toward areas possibly needing further study.

  1. Burnout and patient care in junior doctors in Mexico City.

    PubMed

    Toral-Villanueva, Rodrigo; Aguilar-Madrid, Guadalupe; Juárez-Pérez, Cuauhtémoc Arturo

    2009-01-01

    Burnout is known to occur in public service workers leading to a reduction in effectiveness at work. To estimate the prevalence of burnout in junior doctors and its impact on patient care. A cross-sectional study of junior doctors at three hospitals in Mexico City was conducted. Measures used included the Maslach Burnout Inventory (MBI), measuring depersonalization (DP), emotional exhaustion (EE) and personal achievement (PA), a questionnaire about patient care practices and attitudes and one on sociodemographic characteristics. Logistic regression analysis was used to assess the association between burnout and suspected risk factors. A total of 312 junior doctors participated (response rate 65%). In total, 57% were male and the average age was 28. Average scores in MBI subscales were EE: 18.2, DP: 6.9 and PA: 37.6. Burnout prevalence was 40% (126). Junior doctors with burnout were more likely to report suboptimal patient care practices occurring monthly (OR 5.5; 95% CI 2.7-11.2) and weekly (OR 5.2; 95% CI 1.6-16.3). The logistic regression model for burnout included shifts lasting >12 h, current depression, former major depression, first- or second-year junior doctors, male gender and single status. Burnout was most strongly associated with shifts >12 h and with both current and previous depression. Reported suboptimal patient care was also associated with working shifts of >or=12 h. Burnout may be adversely affecting junior doctors' health and their patients' care.

  2. Water management for a megacity: Mexico City Metropolitan Area.

    PubMed

    Tortajada, Cecilia; Castelán, Enrique

    2003-03-01

    The paper presents an overview of the present situation of the Mexico City Metropolitan Area (MCMA). The analysis indicates an urgent need to radically improve the current water supply and wastewater management practices, to become sustainable. The MCMA is one of the most rapidly growing urban centers of the world, with a population of about 21 million people, a very high rate of immigration and numerous illegal settlements. In order to meet the increasing water demand, successive governments have focused almost exclusively on supply management and engineering solutions, which have resulted in investments of hundreds of millions of USD and the construction of major infrastructure projects for interbasin water transfer. Environmental, economic and social policies associated with water management are mostly inadequate and insufficient, which is resulting in increasing deterioration in the environment, health and socioeconomic conditions of a population living in one of the largest urban agglomerations of the world. Surprisingly, however, no long-term strategies on demand-management, reuse, conservation, and improved water-management practices have been developed so far.

  3. Rapid ethnographic assessment of breastfeeding practices in periurban Mexico City.

    PubMed Central

    Guerrero, M. L.; Morrow, R. C.; Calva, J. J.; Ortega-Gallegos, H.; Weller, S. C.; Ruiz-Palacios, G. M.; Morrow, A. L.

    1999-01-01

    Before carrying out a breastfeeding promotion programme in a periurban area of Mexico City, we conducted a rapid ethnographic study to determine the factors associated with absence of exclusive breastfeeding. The responses to pilot interviews were used to develop a standardized questionnaire regarding reasons for infant feeding choice, sources of advice, and barriers to breastfeeding. We interviewed a random sample of 150 mothers with a child < 5 years of age; 136 (91%) of them had initiated breastfeeding; but only 2% exclusively breastfed up to 4 months. The mothers consistently stated that the child's nutrition, health, growth, and hygiene were the main reasons for the type of feeding selected; cost, comfort, and the husband's opinion were less important. Physicians were ranked as the most important source of advice. Reduction or cessation of breastfeeding occurred on the doctor's advice (68%); or when the mothers encountered local folk illnesses such as "coraje" (52%) or "susto" (54%), which are associated with anger or fright; or had "not enough milk" (62%) or "bad milk" (56%); or because of illness of the mother (56%) or child (43%). During childhood illnesses and conditions, breastfeeding was reduced and the use of supplementary foods was increased. This study emphasizes the importance of cultural values in infant feeding choices, defines specific barriers to breastfeeding, and provides a basis for interventions to promote exclusive breastfeeding in the study population. PMID:10327711

  4. Characteristics of private abortion services in Mexico City after legalization.

    PubMed

    Schiavon, Raffaela; Collado, Maria Elena; Troncoso, Erika; Soto Sánchez, José Ezequiel; Zorrilla, Gabriela Otero; Palermo, Tia

    2010-11-01

    In 2007, first trimester abortion was legalized in Mexico City, and the public sector rapidly expanded its abortion services. In 2008, to obtain information on the effect of the law on private sector abortion services, we interviewed 135 physicians working in private clinics, located through an exhaustive search. A large majority of the clinics offered a range of reproductive health services, including abortions. Over 70% still used dilatation and curettage (D&C); less than a third offered vacuum aspiration or medical abortion. The average number of abortions per facility was only three per month; few reported more than 10 abortions monthly. More than 90% said they had been offering abortion services for less than 20 months. Many women are still accessing abortion services privately, despite the availability of free or low-cost services at public facilities. However, the continuing use of D&C, high fees (mean of $157-505), poor pain management practices, unnecessary use of ultrasound, general anaesthesia and overnight stays, indicate that private sector abortion services are expensive and far from optimal. Now that abortions are legal, these results highlight the need for private abortion providers to be trained in recommended abortion methods and quality of private abortion care improved. Copyright © 2010 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

  5. [Bordetella pertussis in adolescent students in Mexico City].

    PubMed

    Sandoval, Patricia Tomé; Arreola, Laura Del Pilar Torres; Quechol, Guillermina Romero; Gallardo, Héctor Guiscafré

    2008-08-01

    To estimate seroprevalence of Bordetella pertussis in students and their community. A total of 12,273 adolescent students aged 12 to 15 years from 14 public high schools in Mexico City were studied from September 2002 to March 2003. Nasopharyngeal samples were collected from those adolescents with whooping cough for more than 14 days. Infection was confirmed using polymerase chain reaction (PCR). All students, school staff and family exposed to PCR-confirmed cases were tested. Whooping cough rate was 5 to 1,000 students. Of those students (61) who were identified with whooping cough for more than 14 days, 20 (32.8%) were positive to Bordetella pertussis. Of 152 people exposed (contacts) to these cases, 16 (10.6%) were positive and only eight (50%) had whooping cough. One of these exposed (contacts) was the principal of a school that had more than 60% positive cases (12/20) and who was also a teacher of 10 infected students. Of 29 family members tested, eight (27.6%) were positive and from three different families. The study results show a similar rate of whooping cough in adolescents as seen in other countries. Since persistent cough is not always clinically seen in all infected individuals, there may be asymptomatic cases of Bordetella infection.

  6. Infrared Absorption by Atmospheric Aerosols in Mexico City during MILAGRO.

    NASA Astrophysics Data System (ADS)

    Kelley, K. L.; Mangu, A.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    Past research in our group using cylindrical internal reflectance spectroscopy has indicated that aqueous aerosols could contribute to the radiative warming as greenhouse species (1,2). Although aerosol radiative effects have been known for sometime and are considered one of the major uncertainties in climate change modeling, most of the studies have focused on the forcing due to scattering and absorption of radiation in the uv- visible region (3). Infrared spectral information also allows the confirmation of key functional groups that are responsible for enhanced absorption observations from secondary organics in the uv-visible region. This work extends our efforts to evaluate the infrared absorption by aerosols, particularly organics, that are now found to be a major fraction of urban and regional aerosols in the 0.1 to 1.0 micron size range and to help identify key types of organics that can contribute to aerosol absorption. During the MILAGRO campaign, quartz filter samples were taken at 12-hour intervals from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. These samples were taken at the two super-sites, T-0 (Instituto Mexicano de Petroleo in Mexico City) and T-1 (Universidad Technologica de Tecamac, State of Mexico). The samples have been characterized for total carbon content (stable isotope mass spectroscopy) and natural radionuclide tracers, as well as for their UV-visible spectroscopic properties by using integrating sphere diffuse reflectance spectroscopy (Beckman DU with a Labsphere accessory). These same samples have been characterized in the mid and near infrared spectral ranges using diffuse reflection spectroscopy (Nicolet 6700 FTIR with a Smart Collector accessory). Aerosol samples were removed from the surfaces of the aerosol filters by using Si-Carb sampler. The samples clearly indicate the presence of carbonyl organic constituents and the spectra are quite similar to those observed for humic and fulvic acids

  7. Mexico

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of Mexico was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. In areal extent, Mexico is the third largest country on the continent of North America (not counting Greenland, which is a province of Denmark), comprised of almost 2 million square kilometers (756,000 square miles) of land. Home to roughly 100 million people, Mexico is second only to the United States in population, making it the world's largest Spanish-speaking nation. To the north, Mexico shares its border with the United States-a line that runs some 3,100 kilometers (1,900 miles) east to west. About half of this border is defined by the Rio Grande River, which runs southeast to the Gulf of Mexico (partially obscured by clouds in this image) and marks the dividing line between Texas and Mexico. Toward the upper left (northwest) corner of this image is the Baja California peninsula, which provides the western land boundary for the Gulf of California. Toward the northwestern side of the Mexican mainland, you can see the Sierra Madre Occidental Mountains (brownish pixels) running southeast toward Lake Chapala and the city of Guadalajara. About 400 km (250 miles) east and slightly south of Lake Chapala is the capital, Mexico City. Extending northward from Mexico City is the Sierra Madre Oriental Mountains, the irregular line of brownish pixels that seem to frame the western edges of the bright white cumulus clouds in this image. Between these two large mountain ranges is a large, relatively dry highland region. To the south, Mexico shares borders with Guatemala and Belize, both of which are located south of Mexico's Yucatan Peninsula. Image courtesy Reto Stockli, Brian Montgomery, and Robert Simmon, based on data from the MODIS Science Team

  8. Diabetes and Cause-Specific Mortality in Mexico City.

    PubMed

    Alegre-Díaz, Jesus; Herrington, William; López-Cervantes, Malaquías; Gnatiuc, Louisa; Ramirez, Raul; Hill, Michael; Baigent, Colin; McCarthy, Mark I; Lewington, Sarah; Collins, Rory; Whitlock, Gary; Tapia-Conyer, Roberto; Peto, Richard; Kuri-Morales, Pablo; Emberson, Jonathan R

    2016-11-17

    Most large, prospective studies of the effects of diabetes on mortality have focused on high-income countries where patients have access to reasonably good medical care and can receive treatments to establish and maintain good glycemic control. In those countries, diabetes less than doubles the rate of death from any cause. Few large, prospective studies have been conducted in middle-income countries where obesity and diabetes have become common and glycemic control may be poor. From 1998 through 2004, we recruited approximately 50,000 men and 100,000 women 35 years of age or older into a prospective study in Mexico City, Mexico. We recorded the presence or absence of previously diagnosed diabetes, obtained and stored blood samples, and tracked 12-year disease-specific deaths through January 1, 2014. We accepted diabetes as the underlying cause of death only for deaths that were due to acute diabetic crises. We estimated rate ratios for death among participants who had diabetes at recruitment versus those who did not have diabetes at recruitment; data from participants who had chronic diseases other than diabetes were excluded from the main analysis. At the time of recruitment, obesity was common and the prevalence of diabetes rose steeply with age (3% at 35 to 39 years of age and >20% by 60 years of age). Participants who had diabetes had poor glycemic control (mean [±SD] glycated hemoglobin level, 9.0±2.4%), and the rates of use of other vasoprotective medications were low (e.g., 30% of participants with diabetes were receiving antihypertensive medication at recruitment and 1% were receiving lipid-lowering medication). Previously diagnosed diabetes was associated with rate ratios for death from any cause of 5.4 (95% confidence interval [CI], 5.0 to 6.0) at 35 to 59 years of age, 3.1 (95% CI, 2.9 to 3.3) at 60 to 74 years of age, and 1.9 (95% CI, 1.8 to 2.1) at 75 to 84 years of age. Between 35 and 74 years of age, the excess mortality associated with previously

  9. Diabetes and Cause-Specific Mortality in Mexico City

    PubMed Central

    López-Cervantes, Malaquías; Gnatiuc, Louisa; Ramirez, Raul; Hill, Michael; Baigent, Colin; McCarthy, Mark I.; Lewington, Sarah; Collins, Rory; Whitlock, Gary; Tapia-Conyer, Roberto; Peto, Richard

    2016-01-01

    Background Most large, prospective studies of the effects of diabetes on mortality have focused on high-income countries where patients have access to reasonably good medical care and can receive treatments to establish and maintain good glycemic control. In those countries, diabetes less than doubles the rate of death from any cause. Few large, prospective studies have been conducted in middle-income countries where obesity and diabetes have become common and glycemic control may be poor. Methods From 1998 through 2004, we recruited approximately 50,000 men and 100,000 women 35 years of age or older into a prospective study in Mexico City, Mexico. We recorded the presence or absence of previously diagnosed diabetes, obtained and stored blood samples, and tracked 12-year disease-specific deaths through January 1, 2014. We accepted diabetes as the underlying cause of death only for deaths that were due to acute diabetic crises. We estimated rate ratios for death among participants who had diabetes at recruitment versus those who did not have diabetes at recruitment; data from participants who had chronic diseases other than diabetes were excluded from the main analysis. Results At the time of recruitment, obesity was common and the prevalence of diabetes rose steeply with age (3% at 35 to 39 years of age and >20% by 60 years of age). Participants who had diabetes had poor glycemic control (mean [±SD] glycated hemoglobin level, 9.0±2.4%), and the rates of use of other vasoprotective medications were low (e.g., 30% of participants with diabetes were receiving antihypertensive medication at recruitment and 1% were receiving lipid-lowering medication). Previously diagnosed diabetes was associated with rate ratios for death from any cause of 5.4 (95% confidence interval [CI], 5.0 to 6.0) at 35 to 59 years of age, 3.1 (95% CI, 2.9 to 3.3) at 60 to 74 years of age, and 1.9 (95% CI, 1.8 to 2.1) at 75 to 84 years of age. Between 35 and 74 years of age, the excess mortality

  10. Air Quality in Mexico City: Policies Implemented for its Improvement

    NASA Astrophysics Data System (ADS)

    Paramo, V.

    2007-12-01

    Ozone and suspended particles (PM) are two pollutants in the atmosphere of Mexico City Metropolitan Area (MCMA) that still exceed the recommended Mexican health standards. The other criteria pollutants very seldom exceed their corresponding standards. In 2006, the maximum ozone concentrations were above the health standard (0.11 ppm in 1 hour) during 59 percent of the days for an average of 2.2 hours and 130 points of the Air Quality Index (Índice Metropolitano de la Calidad del Aire - IMECA). In contrast, in 1991, 98 percent of the days exceeded the ozone health standard for an average of 6.6 hours and 200 IMECA points. With regards to PM10, in 2006, 80 percent of the sampled concentrations were below the health standard of 120 µg/m3 in 24 hours. However, the annual health standard of 50 µg/m3 is still exceeded. The air quality management in the MCMA is a difficult task due to several adverse factors. The main one is the large population that increased from nearly 15 million in 1992 to more than 18 million at present. As a result, the urban area grows in the adjoined municipalities of the State of Mexico. The vehicular fleet increases also to almost 4 million and the number of industrial facilities is at present 50,000. Consequently, the fuel consumption is very high. The daily energy consumption is estimated to be 44 million liters of equivalent of gasoline. Despite the fact that the air quality has improved in recent years, the related health standards are still exceeded and therefore it is necessary to continue applying the most cost-effective actions to improve the environment quality. Some actions that have contributed most to the reduction of pollutant emissions are the following: Continuous update of the inspection and maintenance program of the vehicular fleet; substitution of the catalytic converters at the end of their useful life; self-regulation of the diesel fleet; use of alternative fuels; update the No-Driving-Day program; establishment of more

  11. Comparison of PAN and Black Carbon Levels in Mexico City: 1997 and 2003

    NASA Astrophysics Data System (ADS)

    Gaffney, J. S.; Marley, N. A.

    2004-12-01

    Peroxyacetyl nitrate (PAN) is a secondary oxidant formed by the oxidation of hydrocarbons in the presence of nitrogen dioxide. PAN is a good indicator compound for hydrocarbon reactivity that leads to ozone formation. Black carbon (BC) is formed by incomplete combustion processes such as diesel soot formation and is a good indicator of primary carbonaceous aerosols in urban areas. We used a fast-response luminol method to measure PAN and BC during the Mexico City Metropolitan Area 2003/Mexico City Megacity 2003 field study in April 2003. We compare these results with our previous PAN measurements in Mexico City during February 1997, made with a gas chromatograph-electron capture detector system. The decreased PAN levels observed in 2003 are consistent with the application of emissions controls on spark ignition gasoline-fueled vehicles, leading to lower levels of the nitrogen oxides and reactive volatile hydrocarbons needed to form PAN. Black carbon data for Mexico City in 2003, taken with a seven-channel aethalometer, are compared with data from 1997, estimated from thermal analyses as elemental carbon (EC). The comparison indicates little change in the levels of BC/EC over the six-year period. This observation is consistent with the application of minimal controls to diesel engines, the likely major source of BC in the Mexico City megacity complex during this period. The authors wish to thank the researchers at Centro Nacional de Investigación en Calidad Ambiental (CENICA), Mexico City. This work was supported by the U.S. Department of Energy, Atmospheric Science Program. We also wish to acknowledge Drs. Mario and Luisa Molina for their help in organizing and directing the Mexico City Metropolitan Area 2003 field study, during which these data were collected.

  12. PM composition and source reconciliation in Mexico City

    NASA Astrophysics Data System (ADS)

    Mugica, V.; Ortiz, E.; Molina, L.; De Vizcaya-Ruiz, A.; Nebot, A.; Quintana, R.; Aguilar, J.; Alcántara, E.

    PM 2.5 and PM 10 were collected during 24-h sampling intervals from March 1st to 31st, 2006 during the MILAGRO campaign carried out in Mexico City's northern region, in order to determine their chemical composition, oxidative activity and the estimation of the source contributions during the sampling period by means of the chemical mass balance (CMB) receptor model. PM 2.5 concentrations ranged from 32 to 70 μg m -3 while that of PM10 did so from 51 to 132 μg m -3. The most abundant chemical species for both PM fractions were: OC, EC, SO 42-, NO 3-, NH 4+, Si, Fe and Ca. The majority of the PM mass was comprised of carbon, up to about 52% and 30% of the PM2.5 and PM10, respectively. PM2.5 constituted more than 50% of PM10. The redox activity, assessed by the dithiothreitol (DTT) assay, was greater for PM 2.5 than for PM 10, and did not display significant differences during the sampling period. The PM 2.5 source reconciliation showed that in average, vehicle exhaust emissions were its most important source in an urban site with a 42% contribution, followed by re-suspended dust with 26%, secondary inorganic aerosols with 11%, and industrial emissions and food cooking with 10% each. These results had a good agreement with the Emission Inventory. In average, the greater mass concentration occurred during O 3S that corresponds to a wind shift initially with transport to the South but moving back to the North. Taken together these results show that PM chemical composition, oxidative potential, and source contribution is influenced by the meteorological conditions.

  13. Depressive symptoms among adolescents and older adults in Mexico City.

    PubMed

    Sánchez-García, Sergio; García-Peña, Carmen; González-Forteza, Catalina; Jiménez-Tapia, Alberto; Gallo, Joseph J; Wagner, Fernando A

    2014-06-01

    Determine the structure of depressive symptoms among adolescents and older adults through the person-centered approach of latent class analysis (LCA). The study is based on data from two independent samples collected in Mexico City (2,444 adolescents and 2,223 older adults) which included the revised version of the CES-D. The presence or absence of depressed mood (dysphoria), diminished pleasure (anhedonia), drastic change in weight, sleep problems, thinking and concentration difficulties, excessive or inappropriate guilt, fatigue, psychomotor agitation/retardation, and suicide ideation were used in LCA to determine the structure of depressive symptoms for adolescents and older adults. Adolescents reported higher excessive or inappropriate guilt compared to older adults, while older adults had higher proportions of anhedonia, sleep problems, fatigue, and psychomotor agitation/retardation. Similar proportions were found in other symptoms. The LCA analysis showed the best fit with four latent classes (LC): LC 1, "symptoms suggestive of major depressive episode (MDE)" with prevalence of 5.9 % (n = 144) and 10.3 % (n = 230) among adolescents and older adults, respectively; LC 2, "probable MDE symptoms" 18.2 % (n = 446) and 23.0 % (n = 512); LC 3, "possible MDE" 27.7 % (n = 676) and 21.8 % (n = 485); LC 4, "without significant depressive symptoms" 48.2 % (n = 1,178) and 44.8 % (n = 996). The differences in item thresholds between the two groups (adolescents vs. older adults) were statistically significant (Wald test = 255.684, df = 1, p < 0.001). This study documented important similarities and differences in the structure of depressive symptoms between adolescents and older adults that merit acknowledgment, further study, and consideration of their potential clinical and public health implications.

  14. Contralateral Autologous Corneal Transplantation Experience in Mexico City.

    PubMed

    Perez-Balbuena, Ana L; Ancona-Lezama, David; Delgado-Pelayo, Sarai; Martinez, Jaime D

    2017-01-01

    The aim of this study is to expand the limited knowledge regarding autologous contralateral penetrating keratoplasty. We report the retrospective outcomes of patients who received autokeratoplasty and contralateral opaque corneas in the donor eye at a tertiary care ophthalmology hospital in Mexico City. Eleven patients received autokeratoplasty and contralateral opaque corneas in the donor eye at our center from 2010 to 2015. The mean patient age at the time of surgery was 58 years (range, 35-85 yrs), with 4 female and 7 male patients. There were no surgical or immediate postsurgical complications in the autokeratoplasty eye. However, 1 patient had expulsive hemorrhage in the sightless eye. Follow-up duration ranged from 11 to 65 months (mean, 26 mo). During follow-up, 3 of the autokeratoplasty procedures failed because of endothelial attenuation. Identified known risk factors for failure of the eye with visual potential included the presence of an Ahmed glaucoma drainage device in 7/11 patients (63%), history of glaucoma in 8/11 (72%), past heterologous penetrating keratoplasty in 2/11 (18%), Vogt-Koyanagi-Harada syndrome in 1/11 (9%), and 4-quadrant corneal vascularization in 1/11 (9%). Autokeratoplasty is a good choice in cases having high risk factors and when fresh corneal tissue is not available. This is the largest study describing outcomes of patients who underwent autokeratoplasty. This technique offers no risk of immune rejection and no need for immunosuppression treatment. This study reports a good prognosis in cases having high risk factors for failure.

  15. Variability of the Mixed-Layer Height Over Mexico City

    NASA Astrophysics Data System (ADS)

    García-Franco, J. L.; Stremme, W.; Bezanilla, A.; Ruiz-Angulo, A.; Grutter, M.

    2018-02-01

    The diurnal and seasonal variability of the mixed-layer height in urban areas has implications for ground-level air pollution and the meteorological conditions. Measurements of the backscatter of light pulses with a commercial lidar system were performed for a continuous period of almost six years between 2011 and 2016 in the southern part of Mexico City. The profiles were temporally and vertically smoothed, clouds were filtered out, and the mixed-layer height was determined with an ad hoc treatment of both the filtered and unfiltered profiles. The results are in agreement when compared with values of mixed-layer height reconstructed from, (i) radiosonde data, and (ii) surface and vertical column densities of a trace gas. The daily maxima of the mean mixed-layer height reach values > 3 km above ground level in the months of March-April, and are clearly lower (< 2.7 km ) during the colder months from September-December. Mean daily minima are typically observed at 0700 local time (UTC - 6h), and are lowest during the winter months with values on average below 500 m. The data presented here show an anti-correlation between high-pollution episodes and the height of the mixed layer. The growth rate of the convective mixed-layer height has a seasonal behaviour, which is characterized together with the mixed-layer-height anomalies. A clear residual layer is evident from the backscattered signals recorded in days with specific atmospheric conditions, but also from the cloud-filtered mean diurnal profiles. The occasional presence of a residual layer results in an overestimation of the reported mixed-layer height during the night and early morning hours.

  16. Variability of the Mixed-Layer Height Over Mexico City

    NASA Astrophysics Data System (ADS)

    García-Franco, J. L.; Stremme, W.; Bezanilla, A.; Ruiz-Angulo, A.; Grutter, M.

    2018-06-01

    The diurnal and seasonal variability of the mixed-layer height in urban areas has implications for ground-level air pollution and the meteorological conditions. Measurements of the backscatter of light pulses with a commercial lidar system were performed for a continuous period of almost six years between 2011 and 2016 in the southern part of Mexico City. The profiles were temporally and vertically smoothed, clouds were filtered out, and the mixed-layer height was determined with an ad hoc treatment of both the filtered and unfiltered profiles. The results are in agreement when compared with values of mixed-layer height reconstructed from, (i) radiosonde data, and (ii) surface and vertical column densities of a trace gas. The daily maxima of the mean mixed-layer height reach values > 3 km above ground level in the months of March-April, and are clearly lower (< 2.7 km) during the colder months from September-December. Mean daily minima are typically observed at 0700 local time (UTC - 6h), and are lowest during the winter months with values on average below 500 m. The data presented here show an anti-correlation between high-pollution episodes and the height of the mixed layer. The growth rate of the convective mixed-layer height has a seasonal behaviour, which is characterized together with the mixed-layer-height anomalies. A clear residual layer is evident from the backscattered signals recorded in days with specific atmospheric conditions, but also from the cloud-filtered mean diurnal profiles. The occasional presence of a residual layer results in an overestimation of the reported mixed-layer height during the night and early morning hours.

  17. Quantification of local and global benefits from air pollution control in Mexico City.

    PubMed

    Mckinley, Galen; Zuk, Miriam; Höjer, Morten; Avalos, Montserrat; González, Isabel; Iniestra, Rodolfo; Laguna, Israel; Martínez, Miguel A; Osnaya, Patricia; Reynales, Luz M; Valdés, Raydel; Martínez, Julia

    2005-04-01

    Complex sociopolitical, economic, and geographical realities cause the 20 million residents of Mexico City to suffer from some of the worst air pollution conditions in the world. Greenhouse gas emissions from the city are also substantial, and opportunities for joint local-global air pollution control are being sought. Although a plethora of measures to improve local air quality and reduce greenhouse gas emissions have been proposed for Mexico City, resources are not available for implementation of all proposed controls and thus prioritization must occur. Yet policy makers often do not conduct comprehensive quantitative analyses to inform these decisions. We reanalyze a subset of currently proposed control measures, and derive cost and health benefit estimates that are directly comparable. This study illustrates that improved quantitative analysis can change implementation prioritization for air pollution and greenhouse gas control measures in Mexico City.

  18. Cost of neurocysticercosis patients treated in two referral hospitals in Mexico City, Mexico.

    PubMed

    Bhattarai, Rachana; Carabin, Hélène; Proaño, Jefferson V; Flores-Rivera, Jose; Corona, Teresa; Flisser, Ana; Budke, Christine M

    2015-08-01

    To estimate annual costs related to the diagnosis, treatment and productivity losses among patients with neurocysticercosis (NCC) receiving treatment at two referral hospitals, the Instituto Nacional de Neurologia y Neurocirugia (INNN) and the Hospital de Especialidades of the Instituto Mexicano del Seguro Social (HE-IMSS), in Mexico City from July 2007 to August 2008. Information on presenting clinical manifestations, diagnostic tests, hospitalisations, surgical procedures and other treatments received by NCC outpatients was collected from medical charts, and supplemented by an individual questionnaire regarding productivity losses and out-of-pocket expenses related to NCC. The annual average per-patient direct costs were US$ 503 (95% CI: 414-592) and US$ 438 (95% CI: 322-571) for patients without a history of hospitalisation and/or surgery seen at the INNN and the HE-IMSS, respectively. These costs increased to US$ 2506 (95% CI: 1797-3215) and US$ 2170 (95% CI: 1303-3037), respectively, for patients with a history of hospitalisation and/or surgery. The average annual per-patient indirect costs were US$ 246 (95% CI: 165-324) and US$ 114 (95% CI: 51-178), respectively, using minimum salary wages for individuals not officially employed. The total annual cost for patients who had and had not been hospitalised and/or undergone a surgical procedure for the diagnosis or treatment of NCC corresponded to 212% and 41% of an annual minimum wage salary, respectively. The disease tends to affect rural socioeconomically disadvantaged populations and creates health disparities and significant economic losses in Mexico. © 2015 John Wiley & Sons Ltd.

  19. Microbiological determinations of some vegetables from the Xochimilco zone in Mexico City, Mexico.

    PubMed

    García-Gómez, Rolando; Chávez-Espinosa, José; Mejía-Chávez, Adriana; Duránde-Bazúa, Carmen

    2002-01-01

    Vegetables intake is widely recommended because of its high content of vitamins, minerals and fiber. However, the irrigation of these vegetables, using wastewaters that have received inadequate treatment often carries unseen microbial pollution that becomes a high risk potential for humans. In the present research, two of the most consumed fresh vegetables cultivated in Mexico City were analyzed, lettuce (Lactuca sativa) and Mexican coriander (Eryngium foetidum). These vegetables are commonly consumed raw. The vegetable choice and the disinfection's method were carried out by the application of two tests to two hundred people in an aleatory form. Similarly, vegetable sampling was carried out by means of a random sampling from the cultivated areas in a chosen "chinampa" (from Náhuatl or Aztec, chinamitl, bulrush or cattail stalks lattice for hydroponics cultivation). Vegetable samples were transferred, in dark plastic bags and in cool boxes at 4 +/- 1.5 degrees C, to the laboratory. Microbiological analysis for Salmonella typhi, mesophilic microorganisms, and fecal coliforms were done according to the "NOM-093SSA1-1994" (Mexico). Results obtained demonstrated that samples treated with the most preferred disinfectant, a colloidal silver based one, had a partial elimination of pathogenic microorganisms found in both vegetables lettuce (Lactuca sativa) and coriander (Eryngium foetidum) samples (mesophyllic microorganisms from 200,000 to 96,500 UFC/g and from 175,000 to 125,000 UFC/g and fecal coliforms from 75 to 0.43 NMP/g and from 150 to 2.10 NMP/g, respectively). Salmonella typhi for all samples gave a positive result. Therefore, it was recommended to the cultivators of the Xochimilco (Náhuatl or Aztec name that means "place where flowers bloom") zone, either stop using contaminated water for irrigation or to use more efficient methods in order to eliminate pathogenic microorganisms, such as diluted chlorine solutions made with commercial cotton clothing bleachers.

  20. Rifting and Subsidence in the Gulf of Mexico: Implications for Syn-rift, Sag, and Salt Sections, and Subsequent Paleogeography

    NASA Astrophysics Data System (ADS)

    Pindell, J. L.; Graham, R.; Horn, B.

    2013-05-01

    Thick (up to 5 km), rapid (<3 Ma), salt deposition is problematic for basin modelling because such accommodation cannot be thermal, yet GoM salt deposits (Late Callovian-Early Oxfordian) appear to be post-rift (most salt overlies planar sub-salt unconformities on syn-rift section). One possible solution is that the pre-drift GoM was a deep (~2 km) air-filled rift depression where basement had already subsided tectonically, and thus could receive up to 5 km of salt, roughly the isostatic maximum on exhumed mantle, hyper-thinned continent, or new ocean crust. ION-GXT and other seismic data along W Florida and NW Yucatán show that (1) mother salt was only 1 km thick in these areas, (2) that these areas were depositionally connected to areas of thicker deposition, and (3) the top of all salt was at global sea level, and hence the sub-salt unconformity along Florida and Yucatán was only 1 km deep by end of salt deposition. These observations fit the air-filled chasm hypothesis; however, two further observations make that mechanism highly improbable: (1) basinward limits of sub-salt unconformities along Florida/Yucatán are deeper than top of adjacent ocean crust emplaced at ~2.7 km subsea (shown by backstripping), and (2) deepest abyssal sediments over ocean crust onlap the top of distal salt, demonstrating that the salt itself was rapidly drowned after deposition. Study of global ION datasets demonstrates the process of "rapid outer marginal collapse" at most margins, which we believe is achieved by low-angle detachment on deep, landward-dipping, Moho-equivalent surfaces such that outer rifted margins are hanging walls of crustal scale half-grabens over mantle. The tectonic accommodation space produced (up to 3 km, < 3 Ma) can be filled by ~5 km of sag/salt sequences with little apparent hanging wall rifting. When salt (or other) deposition lags behind, or ends during, outer marginal collapse, deep-water settings result. We suggest that this newly identified, "outer

  1. Mexico City's Petroleos Mexicanos explosion: disaster management and air medical transport.

    PubMed

    Urquieta, Emmanuel; Varon, Joseph

    2014-01-01

    Mexico City is the largest metropolitan area in the Americas and 1 of the largest in the world; its geographic location and uncontrolled population and industrial growth make this metropolis prone to natural and human-made disasters. Mass casualty disaster responses in Mexico City tend to have complications from multiple logistical and operational challenges. This article focuses on the experiences and lessons learned from an explosion that occurred in a government building in Mexico City and the current status of mass casualty disaster risks and response strategies in Mexico City as well as air medical evacuation, which is a critical component and was shown to be extremely useful in the evacuation of 15 critically ill and polytraumatized patients (Injury Severity Score > 15). Several components of the public and privately owned emergency medical services and health care systems among Mexico City pose serious logistical and operational complications, which finally will be addressed by a joint emergency preparedness council to unify criteria in communications, triage, and incident/disaster command post establishment. Copyright © 2014 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

  2. Extreme Subduction Earthquake Scenarios and their Economical Consequences for Mexico City and Guadalajara, Jalisco, Mexico

    NASA Astrophysics Data System (ADS)

    Chavez, M.; Cabrera, E.; Perea, N.

    2007-05-01

    The destructive effects of large magnitude, thrust subduction superficial (TSS) earthquakes on Mexico City (MC) and Guadalajara (G) has been shown in the recent centuries. For example, the 7/04/1845 a TSS earthquake with Ms 7+ and epicentral distance of about 250 km from MC occurred on the coast of the state of Guerrero, a Maximum Mercalli Modified Intensity (MMI) of IX-X was reported in MC. Furthermore, the 19/09/1985 a Ms 8.1, Mw 8.01, TSS earthquake with epicentral distance of about 340 km from MC occurred on the coast of the state of Michoacan, a maximum MMI of IX-X was reported in MC. Also, the largest, Ms 8.2, instrumentally observed TSS earthquake in Mexico, occurred in the Colima-Jalisco region the 3/06/1932, with epicentral distance of the order of 200 km from G in northwestern Mexico. The 9/10/1995 another similar event, Ms 7.4, Mw 8, with an epicentral distance of about 240 km from G, occurred in the same region and produced MMI IX in the epicentral zone and MMI up to VI in G. The frequency of occurrence of large TSS earthquakes in Mexico is poorly known, but it might vary from decades to centuries [1]. On the other hand, the first recordings of strong ground motions in MC dates from the early 1960´s and most of them were recorded after the 19/09/1985 earthquake. In G there is only one recording of the later event, and 13 for the one occurred the 9/10/1995 [2]. In order to fulfill the lack of strong ground motions records for large damaging TSS earthquakes, which could have an important economical impact on MC [3] and G, in this work we have modeled broadband synthetics (obtained with a hybrid model that has already been satisfactorily compared with observations of the 9/10/1995 Colima-Jalisco Mw 8 earthquake, [4]) expected in MC and G, associated to extreme magnitude Mw 8.5, TSS scenario earthquakes with epicenters in the so-called Guerrero gap and in the Colima-Jalisco zone, respectively. The proposed scenarios are based on the seismic history and up

  3. Nonlinear dynamics of the atmospheric pollutants in Mexico City

    NASA Astrophysics Data System (ADS)

    Muñoz-Diosdado, Alejandro; Barrera-Ferrer, Amilcar; Angulo-Brown, Fernando

    2014-05-01

    The atmospheric pollution in the Metropolitan Zone of Mexico City (MZMC) is a serious problem with social, economical and political consequences, in virtue that it is the region which concentrates both the greatest country population and a great part of commercial and industrial activities. According to the World Health Organization, maximum permissible concentrations of atmospheric pollutants are exceeded frequently. In the MZMC, the environmental monitoring has been limited to criteria pollutants, named in this way due to when their levels are measured in the atmosphere, they indicate in a precise way the air quality. The Automatic Atmospheric Monitoring Network monitors and registers the values of pollutants concentration in air in the MZMC. Actually, it is integrated by approximately 35 automatic-equipped remote stations, which report an every-hour register. Local and global invariant quantities have been widely used to describe the fractal properties of diverse time series. In the study of certain time series, many times it is assumed that they are monofractal, which means that they can be described only with one fractal dimension. But this hypothesis is unrealistic because a lot of time series are heterogeneous and non stationary, so their scaling properties are not the same throughout time and therefore they may require more fractal dimensions for their description. Complexity of the atmospheric pollutants dynamics suggests us to analyze its time series of hourly concentration registers with the multifractal formalism. So, in this work, air concentration time series of MZMC criteria pollutants were studied with the proposed method. The chosen pollutants to perform this analysis are ozone, sulfur dioxide, carbon monoxide, nitrogen dioxide and PM10 (particles less than 10 micrometers). We found that pollutants air concentration time series are multifractal. When we calculate the degree of multifractality for each time series we know that while more

  4. A survey of ²²²Rn in drinking water in Mexico City.

    PubMed

    Vázquez-López, C; Zendejas-Leal, B E; Golzarri, J I; Espinosa, G

    2011-05-01

    In Mexico City there are more than 22 millions of inhabitants (10 in the metropolitan area and 12 in the suburban zone) exposed to drinking water. The local epidemiological authorities recognised that exposure to radon contaminated drinking water is a potential health hazard, as has been considered worldwide. The United States Environmental Protection Agency has proposed a limit of 11.1 Bq l(-1) for the radon level in drinking water. In Mexico a maximum contamination level of radon in drinking water has not yet even considered. In this work, a (222)Rn study of drinking water in Mexico City has revealed a range of concentrations from background level to 3.8 Bq l(-1). (222)Rn was calculated using a portable degassing system (AquaKIT) associated with an AlphaGUARD measuring system. Samples from 70 wells of the water system of the south of the Valley Basin of Mexico City and from houses of some other political administrative divisions of Mexico City were taken.

  5. Lidar Monitoring of Mexico City's Atmosphere During High Air Pollution Episodes

    NASA Technical Reports Server (NTRS)

    Quick, C. R., Jr.; Archuleta, F. L.; Hof, D. E.; Karl, R. R., Jr.; Tiee, J. J., Jr.; Eichinger, W. E.; Holtkamp, D. B.; Tellier, L.

    1992-01-01

    Over the last two decades, Mexico City, like many large industrial and populous urban areas, has developed a serious air pollution problem, especially during the winter months when there are frequent temperature inversions and weak winds. The deteriorating air quality is the result of several factors. The basin within which Mexico City lies in Mexico's center of political, administrative and economic activity, generating 34 percent of the gross domestic product and 42 percent of the industrial revenue, and supporting a population which is rapidly approaching the 20 million mark. The basin is surrounded by mountains on three sides which end up preventing rapid dispersal of pollutants. Emissions from the transportation fleet (more than 3 million vehicles) are one of the primary pollution sources, and most are uncontrolled. Catalytic converters are just now working their way into the fleet. The Mexico City Air Quality Research Initiative in an international collaboration project between the Los Alamos National Laboratory and the Mexican Petroleum Institute are dedicated to the investigation of the air quality problem in Mexico City. The main objective of the project is to identify and assess the cost and benefits of major options being proposed to improve the air quality. The project is organized into three main activity areas: (1) modeling and simulation; (2) characterization and measurements; and (3) strategic evaluation.

  6. [Experiences of street harassment and associations with perceptions of social cohesion among women in Mexico City].

    PubMed

    Campos, Paola A; Falb, Kathryn L; Hernández, Sara; Díaz-Olavarrieta, Claudia; Gupta, Jhumka

    2017-01-01

    To document the frequency and forms of street harassment and examine the association between street harassment experiences and perceptions of social cohesion. Baseline survey data collected among women seeking care in public health clinics in Mexico City were used for analysis. Nearly two-thirds (62.8%) of women reported experiencing some form of street harassment in the prior month; women with street harassment experiences reported significantly lower perceived social cohesion (b=-0.46; 95%CI: -0.69,-0.22). Findings indicate reducing street harassment may have important implications for improving women's perceived social cohesion and their safety in Mexico City.

  7. Historic binnacle of 14C/12C concentration in Mexico City

    NASA Astrophysics Data System (ADS)

    Flores, J. A.; Solís, C.; Huerta, A.; Ortiz, M. E.; Rodríguez-Ceja, M. G.; Villanueva, J.; Chávez, E.

    The radiocarbon concentration is reduced in urban areas, generally due to high CO2 emissions derived from fossil fuels. In this paper, new Δ14C measurements in cellulose extracted from the growth rings of two trees over a 43-year period are presented. The first is in a zone with clean air (El Nayar, Durango, Mexico) and the second is from the Greater Mexico City area (Chapultepec). Data from El Nayar is consistent with that reported for Zone 2 of the Northern Hemisphere while that from the urban area shows a significant decrease in Δ14C. Our results are compared with data from other cities (Nagoya, Japan and Valladolid, Spain).

  8. Exploring the connections between traumatic brain injury caregiver mental health and family dynamics in Mexico City, Mexico.

    PubMed

    Perrin, Paul B; Stevens, Lillian F; Sutter, Megan; Hubbard, Rebecca; Díaz Sosa, Dulce María; Espinosa Jove, Irma Guadalupe; Arango-Lasprilla, Juan Carlos

    2013-10-01

    To examine the patterns of family dynamics that are most associated with the mental health of traumatic brain injury (TBI) caregivers from Mexico. It was hypothesized that healthier family dynamics would be associated with better caregiver mental health. A cross-sectional study of self-reported data collected from TBI caregivers through the Mexican National Institute of Rehabilitation in Mexico City, Mexico, the premier public medical facility in Mexico that provides rehabilitation services to patients with various disabilities. One public outpatient medical and rehabilitation facility. Sixty-eight caregivers of individuals with moderate-to-severe TBI from Mexico City, Mexico, were related to an individual with TBI who was ≥3 months after injury, a primary caregiver for ≥3 months, familiar with the patient's history, and without neurologic or psychiatric conditions. The average (standard deviation) age of caregivers was 50.94 ± 12.85 years), and 82% were women. The caregivers completed Spanish versions of instruments that assessed their own mental health and family dynamics. Outcomes assessed included family dynamics (Family Adaptability and Cohesion Evaluation Scale-Fourth Edition; Family Communication Scale; Family Satisfaction Scale; Family Assessment Device-General Functioning; and Relationship-Focused Coping Scale), and caregiver mental health (Patient Health Questionnaire-9, Zarit Burden Interview, and Satisfaction with Life Scale). Results of canonical correlation analyses suggested that caregiver mental health and family dynamics were positively related, with a large effect size. Caregivers with high family satisfaction and cohesion tended to have a low burden and high satisfaction with life. In addition, caregiver depression and burden were positively related to each other and were both inversely related to caregiver satisfaction with life. TBI caregiver interventions in Latino populations would likely benefit from including programming or

  9. Illuminating sesmic discontinuities with receiver functions from a dense array in Mexico City

    NASA Astrophysics Data System (ADS)

    Perez-Campos, X.; Rodríguez-Domínguez, M. Á.; González-López, A.; Espindola, V. H.; Quintanar, L.; Ramirez-Guzman, L.

    2017-12-01

    Mexico City, with close to 10 million inhabitants, has grown over a sedimentary basin, from an old dried lake. This has been a big factor in amplifying the seismic waves from large subduction earthquakes, located > 300 km away on the Pacific coast, which represents a significant hazard. For this reason, it is of great interest to improve the knowledge of the seismic structure of the city and its details on spatial variations to reduce the uncertainty in ground motion modeling. In May 2017, such array started its way in Mexico City. It consists of 18 broadband stations, that record in place for 3-5 days, moving then to a new location. In total, the city will be covered with 343 recording sites. In this work, we present preliminary results of receiver functions obtained in such array and in permanent stations of the Seismic Network of the Valley of Mexico. Despite the few teleseismic events, the small spacing between stations ( 500 m) allows identification of converted Ps phases from the Moho discontinuity, as well as other converted phases, which might be related to subtle changes in the vertical and lateral seismic structure. This Project was funded by the Secretaria de Ciencia, Tecnología e Innovación (SECITI) of Mexico City. Project SECITI/073/2016.

  10. Aerosol climatology over Mexico City basin: Characterization of their optical properties

    NASA Astrophysics Data System (ADS)

    Carabali-Sandoval, Giovanni; Valdéz-Barrón, Mauro; Bonifaz-Alfonso, Roberto; Riveros-Rosas, David; Estévez, Héctor

    2015-04-01

    Climatology of aerosol optical depth (AOD), single scattering albedo (SSA) and size parameters were analyzed using a 15-year (1999-2014) data set from AErosol RObotic NETwork (AERONET) observations over Mexico City basin. Since urban air pollution is one of the biggest problems that face this megacity, many studies addressing these issues have been published. However few studies have examined the climatology of aerosol taking into account their optical properties over long-time period. Pollution problems in Mexico City have been generated by the daily activities of some 21 million people coupled with the vast amount of industry located within the city's metropolitan area. Another contributing factor is the unique geographical setting of the basin encompassing Mexico City. The basin covers approximately 5000 km2 of the Mexican Plateau at an average elevation of 2250 m above sea level (ASL) and is surrounded on three sides by mountains averaging over 3000 m ASL. In this work we present preliminary results of aerosol climatology in Mexico City.

  11. Subsidence Induced Faulting Hazard Zonation Using Persistent Scatterer Interferometry and Horizontal Gradient Mapping in Mexican Urban Areas

    NASA Astrophysics Data System (ADS)

    Cabral-Cano, E.; Cigna, F.; Osmanoglu, B.; Dixon, T.; Wdowinski, S.

    2011-12-01

    Subsidence and faulting have affected Mexico city for more than a century and the process is becoming widespread throughout larger urban areas in central Mexico. This process causes substantial damages to the urban infrastructure and housing structures and will certainly become a major factor to be considered when planning urban development, land use zoning and hazard mitigation strategies in the next decades. Subsidence is usually associated with aggressive groundwater extraction rates and a general decrease of aquifer static level that promotes soil consolidation, deformation and ultimately, surface faulting. However, local stratigraphic and structural conditions also play an important role in the development and extension of faults. In all studied cases stratigraphy of the uppermost sediment strata and the structure of the underlying volcanic rocks impose a much different subsidence pattern which is most suitable for imaging through satellite geodetic techniques. We present examples from several cities in central Mexico: a) Mexico-Chalco. Very high rates of subsidence, up to 370 mm/yr are observed within this lacustrine environment surrounded by Pliocene-Quaternary volcanic structures. b) Aguascalientes where rates up to 90 mm/yr in the past decade are observed, is controlled by a stair stepped N-S trending graben that induces nucleation of faults along the edges of contrasting sediment package thicknesses. c) Morelia presents subsidence rates as high as 80 mm/yr. Differential deformation is observed across major basin-bounding E-W trending faults and with higher subsidence rates on their hanging walls, where the thickest sequences of compressible Quaternary sediments crop out. Our subsidence and faulting study in urban areas of central Mexico is based on a horizontal gradient analysis using displacement maps from Persistent Scatterer InSAR that allows definition of areas with high vulnerability to surface faulting. Correlation of the surface subsidence pattern

  12. Mexico City air quality research initiative. Volume 2, Problem definition, background, and summary of prior research

    SciTech Connect

    Not Available

    1994-06-01

    Air pollution in Mexico City has increased along with the growth of the city, the movement of its population, and the growth of employment created by industry. The main cause of pollution in the city is energy consumption. Therefore, it is necessary to take into account the city`s economic development and its prospects when considering the technological relationships between well-being and energy consumption. Air pollution in the city from dust and other particles suspended in the air is an old problem. However, pollution as we know it today began about 50 years ago with the growth of industry, transportation, andmore » population. The level of well-being attained in Mexico City implies a high energy use that necessarily affects the valley`s natural air quality. However, the pollution has grown so fast that the City must act urgently on three fronts: first, following a comprehensive strategy, transform the economic foundation of the city with nonpolluting activities to replace the old industries, second, halt pollution growth through the development of better technologies; and third, use better fuels, emission controls, and protection of wooded areas.« less

  13. Tuberculosis disease among Mexico-born individuals living in New York City, 2001-2014.

    PubMed

    Stennis, N L; Meissner, J S; Bhavnani, D; Kreiswirth, B; Ahuja, S Desai

    2017-06-01

    Tuberculosis (TB) has decreased substantially in New York City (NYC), but progress has slowed in recent years. Continued declines will require novel approaches tailored to foreign-born populations. To describe TB epidemiology among the Mexico-born population of NYC to inform interventions in this community. The study included NYC patients with TB disease identified from 2001 to 2014. Incidence rates were compared by country of birth groupings. Demographic and patient characteristics were analyzed for all Mexico-born TB patients. Patients were compared by Mycobacterium bovis vs. non-M. bovis TB strain. Culture-confirmed patients were compared by genotype clustering status. From 2001 to 2014, 621 Mexico-born TB patients were identified in NYC. TB rates were significantly higher among Mexico-born vs. US-born persons every year. Mexico-born patients had lived in the United States for a median 7 years at diagnosis. The geographic distribution of Mexico-born TB patients was similar to that of the total Mexico-born population. Overall, 71% of patients reported previous employment; 52% of non-M. bovis patients were clustered based on genotyping results. Our results provide a foundation to inform future interventions in the Mexico-born population. Additional work is needed to explore possible local TB transmission and health care-seeking practices.

  14. The Psychosocial Meaning of Pregnancy among Adolescents in Mexico City.

    ERIC Educational Resources Information Center

    Atkin, Lucille C.; Alatorre-Rico, Javier

    Adolescent childbearing has historically been a relatively frequent phenomenon in Mexico and has only recently begun to decline. This study was designed to identify to what extent urban Mexican adolescents, who became pregnant out-of-wedlock and who carried their pregnancy to term, received social support during pregnancy and their emotional…

  15. The prehospital emergency care system in Mexico City: a system's performance evaluation.

    PubMed

    Peralta, Luis Mauricio Pinet

    2006-01-01

    Mexico City has one of the highest mortality rates in Mexico, with non-intentional injuries as a leading cause of death among persons 1-44 years of age. Emergency medical services (EMS) in Mexico can achieve high levels of efficiency by offering high quality medical care at a low cost through adequate system design. The objective of this study was to determine whether the prehospital EMS system in Mexico City meets the criteria standards established by the American Ambulance Association Guide for Contracting Emergency Medical Services (AAA Guide) for highly efficient EMS systems. This retrospective, descriptive study, evaluated the structure of Mexico City's EMS system and analyzed EMS response times, clinical capacity, economic efficiency, and customer satisfaction. These results were compared with the AAA guide, according to the soc ial, economic, and political context in Mexico. This paper describes the healthcare system structure in Mexico, followed by a description of the basic structure of EMS in Mexico City, and of each tenet described in the AAA guide. The p aper includesdata obtained from official documents and databases of government agencies, and operative and administrative data from public and private EMS providers. The quality of the data for response times (RT) were insufficient and widely varied among providers, with a minimum RT of 6.79 minutes (min) and a maximum RT of 61 min. Providers did not define RT clearly, and measured it with averages, which can hide potentially poor performance practices. Training institutions are not required to follow a standardized curriculum. Certifications are the responsibility of the individual training centers and have no government regulation. There was no evidence of active medical control involvement in direct patient care, and providers did not report that quality assurance programs were in place. There also are limited career advancement opportunities for EMS personnel. Small economies of scale may not allow

  16. Traumatic Events and Suicide-Related Outcomes among Mexico City Adolescents

    ERIC Educational Resources Information Center

    Borges, Guilherme; Benjet, Corina; Medina-Mora, Maria Elena; Orozco, Ricardo; Molnar, Beth E.; Nock, Matthew K.

    2008-01-01

    Background: We report the prevalence and associations between traumatic events and suicidal ideation, suicide plans and suicide attempts among Mexican adolescents. Methods: The data are from a representative multistage probability household survey of 3,005 adolescents aged 12 to 17 years residing in the Mexico City Metropolitan Area that was…

  17. Abandonment, Adoption and Reproductive Disruption: Transitions in Child Circulation in Mexico City, 1880-1910

    ERIC Educational Resources Information Center

    Blum, Ann S.

    2007-01-01

    To explore meanings attached to children in Mexican society, this article examines two changing aspects of child circulation, a widespread reproductive disruption to the families of Mexico City's working poor. In the late 1890s, a rapid rise in admissions to the public foundling home was matched by a striking increase in retrievals. At the other…

  18. The Correlation of Secondary Organic Aerosol with Odd Oxygen in Mexico City

    EPA Science Inventory

    Data from a mountain location intercepting the Mexico City emission plume demonstrate a strong correlation between secondary organic aerosol and odd-oxygen (O3 + NO2). The measured oxygenated-organic aerosol correlates with odd-oxygen measurements with an a...

  19. Summary of air pollution impacts on forests in the Mexico City air basin

    Treesearch

    Mark E. Fenn; L.I. de Bauer; Tomás Hernández-Tejeda

    2002-01-01

    Oxidant air pollution symptoms were first reported in bioindicator plants in the Mexico City Air Basin (MCAB) in 1971 (de Bauer 1972). Classic injury symptoms on well-known bioindicator plants strongly supported the presumption that symptoms were caused by photochemical oxidants, of which ozone (O3) is the primary pollutant. Symptoms in indicator...

  20. Ideal Images of Educational Leadership in Mexico City and South Texas

    ERIC Educational Resources Information Center

    Slater, Charles L.; Boone, Mike; Alvarez, Isaias; Topete, Carlos; Iturbe, Elizabeth; Base, Melinda; Fillion, Sharon; Galloway, Holly; Korth, Lisa Elena; Munoz, Linda

    2006-01-01

    This study used a qualitative approach to analyze ideal images of educational leadership among administrators in Mexico City and South Texas. Looking at educational leadership from a cross-cultural perspective revealed issues that are hidden when working in just one culture. Though both groups indicated that participation, clear communication,…

  1. Spatial Analysis of the Level of Exposure to Seismic Hazards of Health Facilities in Mexico City, Mexico

    NASA Astrophysics Data System (ADS)

    Moran, S.; Novelo-Casanova, D. A.

    2011-12-01

    Although health facilities are essential infrastructure during disasters and emergencies, they are also usually highly vulnerable installations in the case of the occurrence of large and major earthquakes. Hospitals are one of the most complex critical facilities in modern cities and they are used as first response in emergency situations. The operability of a hospital must be maintained after the occurrence of a local strong earthquake in order to satisfy the need for medical care of the affected population. If a health facility is seriously damaged, it cannot fulfill its function when most is needed. In this case, hospitals become a casualty of the disaster. To identify the level of physical exposure of hospitals to seismic hazards in Mexico City, we analyzed their geographic location with respect to the seismic response of the different type of soils of the city from past earthquakes, mainly from the events that occurred on September 1985 (Ms= 8.0) and April 1989 (Ms= 6.9). Seismic wave amplification in this city is the result of the interaction of the incoming seismic waves with the soft and water saturated clay soils, on which a large part of Mexico City is built. The clay soils are remnants of the lake that existed in the Valley of Mexico and which has been drained gradually to accommodate the growing urban sprawl. Hospital facilities were converted from a simple database of names and locations into a map layer of resources. This resource layer was combined with other map layers showing areas of seismic microzonation in Mexico City. This overlay was then used to identify those hospitals that may be threatened by the occurrence of a large or major seismic event. We analyzed the public and private hospitals considered as main health facilities. Our results indicate that more than 50% of the hospitals are highly exposed to seismic hazards. Besides, in most of these health facilities we identified the lack of preventive measures and preparedness to reduce their

  2. An assessment of air pollutant exposure methods in Mexico City, Mexico.

    PubMed

    Rivera-González, Luis O; Zhang, Zhenzhen; Sánchez, Brisa N; Zhang, Kai; Brown, Daniel G; Rojas-Bracho, Leonora; Osornio-Vargas, Alvaro; Vadillo-Ortega, Felipe; O'Neill, Marie S

    2015-05-01

    Geostatistical interpolation methods to estimate individual exposure to outdoor air pollutants can be used in pregnancy cohorts where personal exposure data are not collected. Our objectives were to a) develop four assessment methods (citywide average (CWA); nearest monitor (NM); inverse distance weighting (IDW); and ordinary Kriging (OK)), and b) compare daily metrics and cross-validations of interpolation models. We obtained 2008 hourly data from Mexico City's outdoor air monitoring network for PM10, PM2.5, O3, CO, NO2, and SO2 and constructed daily exposure metrics for 1,000 simulated individual locations across five populated geographic zones. Descriptive statistics from all methods were calculated for dry and wet seasons, and by zone. We also evaluated IDW and OK methods' ability to predict measured concentrations at monitors using cross validation and a coefficient of variation (COV). All methods were performed using SAS 9.3, except ordinary Kriging which was modeled using R's gstat package. Overall, mean concentrations and standard deviations were similar among the different methods for each pollutant. Correlations between methods were generally high (r=0.77 to 0.99). However, ranges of estimated concentrations determined by NM, IDW, and OK were wider than the ranges for CWA. Root mean square errors for OK were consistently equal to or lower than for the IDW method. OK standard errors varied considerably between pollutants and the computed COVs ranged from 0.46 (least error) for SO2 and PM10 to 3.91 (most error) for PM2.5. OK predicted concentrations measured at the monitors better than IDW and NM. Given the similarity in results for the exposure methods, OK is preferred because this method alone provides predicted standard errors which can be incorporated in statistical models. The daily estimated exposures calculated using these different exposure methods provide flexibility to evaluate multiple windows of exposure during pregnancy, not just trimester or

  3. Effect of air pollution on olfactory function in residents of Mexico City.

    PubMed

    Hudson, Robyn; Arriola, Aline; Martínez-Gómez, Margarita; Distel, Hans

    2006-01-01

    To our knowledge there has been no study of the effect of everyday air pollution on olfactory function. It was therefore the aim of this study to compare the olfactory performance of long-term residents of Mexico City, an environment with high air pollution, with the olfactory performance of residents of the Mexican state of Tlaxcala, a region geographically similar to Mexico City but with low air pollution. Healthy volunteers [82 Mexico City subjects (MEX), 86 Tlaxcala subjects (TLX)] 20-63 years of age and balanced for age and gender between the two localities were tested for the perception of the odors of everyday beverages presented in squeeze bottles. When tested with ascending concentrations of stimuli in a three-way oddball paradigm, residents of Tlaxcala detected the odors of instant coffee and of an orange drink at significantly lower concentrations than residents of Mexico City. They also performed significantly better in discriminating between the two similar-smelling Mexican beverages horchata and atole in an oddball test. Significant differences between the two populations in overall olfactory performance were apparent in three of the four age classes (20- to 29-, 30- to 39-, and 40- to 49-year-old subjects) but not in the 50-63 years age class. About 10% of MEX subjects compared to about 2% of TLX subjects were judged to have poor olfactory function; all were from the older age classes (mean age: 48.6 years). Thus, air pollution in Mexico City appears to have a substantial impact on olfactory function even in young and middle-aged residents.

  4. Biophysical, infrastructural and social heterogeneities explain spatial distribution of waterborne gastrointestinal disease burden in Mexico City

    NASA Astrophysics Data System (ADS)

    Baeza, Andrés; Estrada-Barón, Alejandra; Serrano-Candela, Fidel; Bojórquez, Luis A.; Eakin, Hallie; Escalante, Ana E.

    2018-06-01

    Due to unplanned growth, large extension and limited resources, most megacities in the developing world are vulnerable to hydrological hazards and infectious diseases caused by waterborne pathogens. Here we aim to elucidate the extent of the relation between the spatial heterogeneity of physical and socio-economic factors associated with hydrological hazards (flooding and scarcity) and the spatial distribution of gastrointestinal disease in Mexico City, a megacity with more than 8 million people. We applied spatial statistics and multivariate regression analyses to high resolution records of gastrointestinal diseases during two time frames (2007–2009 and 2010–2014). Results show a pattern of significant association between water flooding events and disease incidence in the city center (lowlands). We also found that in the periphery (highlands), higher incidence is generally associated with household infrastructure deficiency. Our findings suggest the need for integrated and spatially tailored interventions by public works and public health agencies, aimed to manage socio-hydrological vulnerability in Mexico City.

  5. NO2 and HCHO variability in Mexico City from MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Grutter, M.; Friedrich, M. M.; Rivera, C. I.; Arellano, E. J.; Stremme, W.

    2015-12-01

    Atmospheric studies in large cities are of great relevance since pollution affects air quality and human health. A network of Multi Axis Differential Optical Absorption Spectrometers (MAX-DOAS) has been established in strategic sites within the Mexico City metropolitan area. Four instruments are now in operation with the aim to study the variability and spatial distribution of key pollutants, providing results of O4, NO2 and HCHO slant column densities (SCD). A numerical code has been written to retrieve gas profiles of NO2 and HCHO using radiative transfer simulations. We present the first results of the variability of these trace gases which will bring new insight in the current knowledge of transport patterns, emissions as well as frequency and origin of extraordinary events. Results of the vertical column densities (VCD) valiability of NO2 and HCHO in Mexico City are presented. These studies are useful to validate current and future satellite observatopns such as OMI, TROPOMI and TEMPO.

  6. Asthma prevalence in children living in north Mexico City and a comparison with other Latin American cities and world regions.

    PubMed

    Del-Rio-Navarro, Blanca; Del Rio-Chivardi, Jaime Mariano; Berber, Arturo; Sienra-Monge, Juan Jose Luis; Rosas-Vargas, Miguel Angel; Baeza-Bacab, Manuel

    2006-01-01

    Reports of previous studies done without following the international guidelines in different cities of Mexico showed a decrease in asthma prevalence. The aim of this study was to determine the prevalence and severity of asthma symptoms in children and teenagers living in north Mexico City and compare them with those of other Latin American cities and world regions. The cross-sectional survey followed the protocol of the International Study of Asthma and Allergies in Childhood IIIb phase survey. The study population included children 6-7 years old and teenagers 13-14 years old from randomly selected primary and secondary schools. There were 1629 boys and 1582 girls in the group of 6- to 7-year-old children and 2039 boys and 1860 girls in the 13- to 14-year-old group. "Wheezing or whistling in the chest at any time in the past" was present in 19.2% (95% confidence interval [CI], 17.9, 20.6) of the children and in 17.0% (95% CI, 15.8, 18.1) of the teenagers; "wheezing or whistling in the chest in the last 12 months" was reported in 6.8% (95% CI, 5.9, 7.6) of the children and 9.9% (95% CI, 9.0, 10.8) of the teenagers; "asthma ever" was claimed in 4.5% (95% CI, 3.8, 5.2) of the children and 8.0% (95% CI, 7.1, 8.8) of the teenagers. These prevalences were low compared with other ISAAC Latin American surveys and intermediate in comparison with worldwide regional prevalences reported by ISAAC surveys. The prevalence of asthma is low in Mexico City in comparison with other surveyed locations, but the number of patients with asthma makes it an important issue for Mexican public health programs.

  7. Seroepidemiology of cytomegalovirus infection in pregnant women in Durango City, Mexico.

    PubMed

    Alvarado-Esquivel, Cosme; Hernández-Tinoco, Jesús; Sánchez-Anguiano, Luis Francisco; Ramos-Nevárez, Agar; Cerrillo-Soto, Sandra Margarita; Estrada-Martínez, Sergio; Martínez-Ramírez, Lucio; Pérez-Álamos, Alma Rosa; Guido-Arreola, Carlos Alberto

    2014-09-05

    Cytomegalovirus causes congenital infections all around the world. The seroepidemiology of cytomegalovirus infection in pregnant women in Mexico is largely unknown. We sought to determine the seroprevalence of cytomegalovirus infection in pregnant women in Durango City, Mexico; and to determine seroprevalence association with socio-demographic, clinical and behavioral characteristics of pregnant women. Through a cross-sectional study design, 343 pregnant women were examined for anti-cytomegalovirus IgG and IgM antibodies in Durango City, Mexico. We used a standardized questionnaire to obtain the general characteristics of the pregnant women. Multivariate analysis was performed to determine the association of cytomegalovirus infection with the characteristics of the pregnant women. Anti-CMV IgG and IgM antibodies were detected in 225 (65.6%) and in none of the 343 pregnant women studied, respectively. Multivariate analysis showed that CMV exposure was associated with increasing age (OR = 1.67; 95% CI: 1.01-2.76; P = 0.04). Other women characteristics including socioeconomic status, education, blood transfusion, transplantation, sexual promiscuity and number of previous pregnancies or deliveries did not show an association with CMV exposure. This is the first seroepidemiology study of CMV infection in pregnant women in Mexico. A number of known factors associated with CMV infection were not associated with CMV exposure in the women studied. Further studies to determine routes of CMV infection in pregnant women in Mexico are needed.

  8. Environmental urban lead exposure and blood lead levels in children of Mexico City.

    PubMed Central

    Romieu, I; Carreon, T; Lopez, L; Palazuelos, E; Rios, C; Manuel, Y; Hernandez-Avila, M

    1995-01-01

    Lead contamination is now a leading public health problem in Mexico. However, there are few data on the lead content of various environmental sources, and little is known about the contribution of these sources to the total lead exposure in the population of children residing in Mexico City. We conducted a cross-sectional study in a random sample of 200 children younger than 5 years of age who lived in one of two areas of Mexico City. Environmental samples of floor, window, and street dust, paint, soil, water, and glazed ceramics were obtained from the participants' households, as well as blood samples and dirt from the hands of the children. Blood lead levels ranged from 1 to 31 micrograms/dl with a mean of 9.9 micrograms/dl (SD 5.8 micrograms/dl). Forty-four percent of the children 18 months of age or older had blood lead levels exceeding 10 micrograms/dl. The lead content of environmental samples was low, except in glazed ceramic. The major predictors of blood lead levels were the lead content of the glazed ceramics used to prepare children's food, exposure to airborne lead due to vehicular emission, and the lead content of the dirt from the children's hands. We conclude that the major sources of lead exposure in Mexico City could be controlled by adequate public health programs to reinforce the use of unleaded gasoline and to encourage production and use of unleaded cookware instead of lead-glazed ceramics. PMID:8605853

  9. [Sensitization to pollens of Oleaceae family in a group of patients from Mexico City].

    PubMed

    Morfín-Maciel, Blanca María; Flores, Iveth; Rosas-Alvarado, Alejandro; Bautista, Maura; López-López, Jorge Roberto

    2009-01-01

    In Mexico City, where the Olive trees are scarce, the Oleaceae family has been recognized as one of the most important causes of pollen allergy, possibly related to cross-reactivity with other pollens of the Oleaceae family, as Fraxinus excelsior, Ligustrum vulgaris and Osmanthus americanus. To know the prevalence of sensitization to the Oleaceae family in Mexico City, cross-reactivity, as well as concurrent sensitizations, and vegetables and fruits associated to oral allergy syndrome (OAS). A prospective, longitudinal study was carried out during two months, among patients who attended the outpatient allergy clinic of the General Hospital of Mexico with symptoms suggestive of respiratory allergy. A questionnaire to search OAS was used, and skin Prick tests to pollens were performed. Among 279 patients, 164 (58.8%) had respiratory allergy and positive skin prick test (SPT) to pollens. Olea europaea had the highest prevalence of SPT reactivity (52.4%), followed by Fraxinus excelsior (43.3%), Ligustrum vulgaris (36.6%) and Osmanthus americanus (15.9%). There were OAS in 53.5%, 50.7%, 50% and 53.8%, respectively, mainly related to peach, apple, kiwi, pear and banana. Olive monosensitization was found in 5.5%. In this study, Olea europaea had the highest prevalence of positive reactivity to pollens in Mexico City, then its sensitization must be determined routinely.

  10. Public opinion on abortion in Mexico City after the landmark reform.

    PubMed

    Wilson, Kate S; García, Sandra G; Díaz Olavarrieta, Claudia; Villalobos-Hernández, Aremis; Rodríguez, Jorge Valencia; Smith, Patricio Sanhueza; Burks, Courtney

    2011-09-01

    This article presents findings from three opinion surveys conducted among representative samples of Mexico City residents: the first one immediately prior to the groundbreaking legalization of first-trimester abortion in April 2007, and one and two years after the reform. Bivariate and multivariate analyses were performed to assess changes in opinion concerning abortion and correlates of favorable opinion following reform. In 2009 a clear majority (74 percent) of respondents were in support of the Mexico City law allowing for elective first-trimester abortion, compared with 63 percent in 2008 and 38 percent in 2007. A significant increase in support for extending the law to the rest of Mexico was found: from 51 percent in 2007 to 70 percent in 2008 and 83 percent in 2009. In 2008 the significant independent correlates of support for the Mexico City law were education, infrequent religious service attendance, sex (being male), and political party affiliation; in 2009 they were education beyond high school, infrequent religious service attendance, and ever having been married.

  11. City of Albuquerque, New Mexico, Municipal Forest Resource Analysis

    Treesearch

    K.E. Vargas; E.G. McPherson; J.R. Simpson; P.J. Peper; S.L. Gardner; Q. Xiao

    2006-01-01

    Albuquerque, a booming southwestern city appreciated for the beauty of its high desert surroundings and its bustling business culture maintains parks and natural areas as an integral component of the urban infrastructure (Figure 1). Recently, Albuquerque was honored by the Trust for Public Land for its excellent park system: it leads the nation in percentage of land...

  12. Detection of mumps virus genotype H in two previously vaccinated patients from Mexico City.

    PubMed

    Del Valle, Alberto; García, Alí A; Barrón, Blanca L

    2016-06-01

    Infections caused by mumps virus (MuV) have been successfully prevented through vaccination; however, in recent years, an increasing number of mumps outbreaks have been reported within vaccinated populations. In this study, MuV was genotyped for the first time in Mexico. Saliva samples were obtained from two previously vaccinated patients in Mexico City who had developed parotitis. Viral isolation was carried out in Vero cells, and the SH and HN genes were amplified by RT-PCR. Amplicons were sequenced and compared to a set of reference sequences to identify the MuV genotype.

  13. [Exposure to fluorides from drinking water in the city of Aguascalientes, Mexico].

    PubMed

    Trejo-Vázquez, R; Bonilla-Petriciolet, A

    2001-08-01

    Determine the fluoride content in all the wells that supply drinking water to the city of Aguascalientes, Mexico, in order to establish the population's degree of exposure. The fluoride content of the 126 wells that supply drinking water to the city of Aguascalientes was determined, using the SPADNS method, in accordance with two Mexican regulations, NMX-AA-77-1982 and NMX-014-SSAI-1993. Using that data, we created fluoride isopleth maps showing the distribution of fluoride concentrations in the water supplies for the city of Aguascalientes. We also estimated exposure doses for the city's inhabitants. The mean analysis uncertainty was 3.9%. Seventy-three wells had a fluoride concentration of" 1.5 mg/L, which was the maximum permissible value set by the Mexican standards then in effect. All the maximum exposure doses surpassed the minimum risk level set by Agency for Toxic Substances and Disease Registry (ATSDR) of the Department of Health and Human Services of the United States of America. In the children under 1 year of age, even the minimum does was slightly higher than the ATSDR risk level. From estimating the fluoride exposure doses caused by water consumption in the city of Aguascalientes and comparing those doses with ones from other states in Mexico, we concluded that the fluoride intake in Aguascalientes represents a potential risk for inhabitants' health. The fluoride content of the city's drinking water should be reduced to 0.69 mg/L.

  14. [Perception of health risks due to air pollution among adolescents in Mexico City].

    PubMed

    Catalán-Vázquez, Minerva; Riojas-Rodríguez, Horacio; Jarillo-Soto, Edgar C; Delgadillo-Gutiérrez, Héctor Javier

    2009-01-01

    Analyze the relations established between air pollution and health-disease-death in a sample of students in Mexico City. Survey of 1274 students from 14 secondary schools in five areas in Mexico City was conducted between March and April of 2003. We used a multi-stage sampling, based in a basic geostatistical areas (AGEB). A total of 84.4% believed that Mexico City has a high, or very high air pollution; that valuation decreases as it approaches the most immediate place in which the students live. The health risks range from effects on respiratory health, 66.9%, to other effects on daily life, 2.2%. The predictors that air pollution is perceived as serious/very serious are: 1) that they associate it with the possibility of causing death (OR= 1.35, 95% CI=1.02-1.77), and 2) that they attend schools located in the La Merced zone, (OR= 2.23, 95% CI= 1.56-3.21). Determinants of perception, such as gender, zone where the school is located and the differences in air quality perceived in the city/area/schools, suggest that focalizing components must be involved in environmental policies, in order to make environmental programs more effective at the local level.

  15. Mexico City air pollution adversely affects olfactory function and intranasal trigeminal sensitivity.

    PubMed

    Guarneros, Marco; Hummel, Thomas; Martínez-Gómez, Margaríta; Hudson, Robyn

    2009-11-01

    Surprisingly little is known about the effects of big-city air pollution on olfactory function and even less about its effects on the intranasal trigeminal system, which elicits sensations like burning, stinging, pungent, or fresh and contributes to the overall chemosensory experience. Using the Sniffin' Sticks olfactory test battery and an established test for intranasal trigeminal perception, we compared the olfactory performance and trigeminal sensitivity of residents of Mexico City, a region with high air pollution, with the performance of a control population from the Mexican state of Tlaxcala, a geographically comparable but less polluted region. We compared the ability of 30 young adults from each location to detect a rose-like odor (2-phenyl ethanol), to discriminate between different odorants, and to identify several other common odorants. The control subjects from Tlaxcala detected 2-phenyl ethanol at significantly lower concentrations than the Mexico City subjects, they could discriminate between odorants significantly better, and they performed significantly better in the test of trigeminal sensitivity. We conclude that Mexico City air pollution impairs olfactory function and intranasal trigeminal sensitivity, even in otherwise healthy young adults.

  16. Continuous measurement of carbon black in a densely populated area of Mexico City

    NASA Astrophysics Data System (ADS)

    Peralta, O.; Ortinez, A.; Castro, T.; Espinoza, M. D. L. L.; Saavedra, I.; Carabali-Sandoval, G. A., Sr.; Páramo, V. H.; Gavilán, A.; Martínez-Arroyo, A.

    2014-12-01

    The black carbon (BC) is a byproduct of burning fossil fuels and is an important short-lived climate forcer because it absorbs solar radiation altering the Earth's radiative budget and climate. It is also an atmospheric pollutant that promotes reactions of other compounds in the atmosphere. Despite its importance for health and climate, in Mexico there are very few studies on ambient concentrations of BC in urban areas and virtually no information of continuous measurements over long periods (more than a month of measurements). So, in order to develop more efficient local and regional mitigation strategies and policies that allow reducing ambient concentrations of BC, it is necessary to know BC seasonal evolution, contribution to radiative budget and impacts on health. This study shows continuous measurements (from July 2013 to July 2014) of BC to perform an analysis of seasonal variations. The selected monitoring site is located at Iztapalapa, a densely populated area with high traffic on the southeastern part of Mexico City. BC concentrations were obtained by two aethalometers (Magee Scientific Company, models AET31 and AET42) placed 15 meters above the ground. The aethalometers operate in the wavelength range of 370-950 nm and use a standard value of mass absorption coefficient MAC = 10.8 m2/g to calculate BC environmental concentration. To correct the aethalometers readings to the conditions of Mexico City, it was employed MAC = to 6.7 m2/g, which was determined for PM2.5 with a carbon analyzer (UIC, Inc.) and represents the mass absorption coefficient of soot emitted in Mexico City. The average value of the corrected concentration of BC in Mexico City during the period from July 2013 to July 2014 was 5.39 ± 1.89 μg/m3 (1.6 higher than readings recorded by aethalometers), which is greater than that measured in Shanghai in 2014 (annual average 2.33 μg/m3) and those reported for some U.S. cities; the value implies a potential danger to the health of

  17. Urban effects on convective precipitation in Mexico city

    NASA Astrophysics Data System (ADS)

    Jauregui, Ernesto; Romales, Ernesto

    This paper reports on urban-related convective precipitation anomalies in a tropical city. Wet season (May-October) rainfall for an urban site (Tacubaya) shows a significant trend for the period 1941-1985 suggesting an urban effect that has been increasing as the city grew. On the other hand, rainfall at a suburban (upwind) station apparently unaffected by urbanization, has remained unchanged. Analysis of historical records of hourly precipitation for an urban station shows that the frequency of intense (> 20 mm h -1) rain showers has increased in recent decades. Using a network of automatic rainfall stations, areal distribution of 24 h isoyets show a series of maxima within the urban perimeter which may be associated to the heat island phenomenon. Isochrones of the beginning of rain are used to estimate direction and speed of movement of the rain cloud cells. The daytime heat island seems to be associated with the intensification of rain showers.

  18. [The control of urban growth in Mexico City. Suppositions regarding poor planning].

    PubMed

    Aguilar, A G; Olvera, G

    1991-01-01

    It is argued that mechanisms for planning land use and controlling urban expansion in Mexico City have failed to achieve their aims. Although in theory Mexico's urban planning process has recently attempted to go beyond purely physical aspects to include socioeconomic dimensions, it has in fact been inflexible and oriented to exclusively to technical and administrative aspects, to the detriment of social distribution goals. Planning instruments have not included important aspects such as specific mechanisms for altering employment structures or income levels or mechanisms for providing access to land or housing to the most disadvantaged groups. The urban planning process in Mexico City, instead of assuming a socially compensatory role in favor of disadvantaged groups, has maintained the status quo or discriminated in favor of the already advantaged. The spatial and technical orientation or urban planning in Mexico City does not leave room for a well-defined social policy. The population of the Mexico City metropolitan Zone increased from 3 million in 1950 to 18 million in 1985, while its total area increased from 11,750 hectares in 1940 to 125,000 in 1985. Transfer of population from the Federal District to the conurban municipios of the state of Mexico has been very significant since the 1970s. Around 20% of the total area of metropolitan Mexico City has been settled through illegal means, with communal and ejido lands accounting for a large share. Settlements on some 60% of lands in metroplitan Mexico City were illegal or irregular at some time. Low income housing is the cheapest form for the government because the frequently illegal status of settlers prevents them from making any demands for services or equipment for the 1st several years. Construction is undertaken and financed almost entirely by the settlers themselves, freeing the government of responsibility in regard to the constitutionally mandated right of all Mexicans to housing. The Urban Development

  19. Particulate polycyclic aromatic hydrocarbon spatial variability and aging in Mexico City

    NASA Astrophysics Data System (ADS)

    Thornhill, D. A.; Herndon, S. C.; Onasch, T. B.; Wood, E. C.; Zavala, M.; Molina, L. T.; Gaffney, J. S.; Marley, N. A.; Marr, L. C.

    2007-11-01

    As part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) study in the Mexico City Metropolitan Area in March 2006, we measured particulate polycyclic aromatic hydrocarbons (PAHs) and other gaseous species and particulate properties at six locations throughout the city. The measurements were intended to support the following objectives: to describe spatial and temporal patterns in PAH concentrations, to gain insight into sources and transformations of PAHs, and to quantify the relationships between PAHs and other pollutants. Total particulate PAHs at the Instituto Mexicano del Petróleo (T0 supersite) located near downtown averaged 50 ng m-3, and aerosol active surface area averaged 80 mm2 m-3. PAHs were also measured on board the Aerodyne Mobile Laboratory, which visited six sites encompassing a mixture of different land uses and a range of ages of air parcels transported from the city core. Weak intersite correlations suggest that local sources are important and variable and that exposure to PAHs cannot be represented by a single regional-scale value. The relationships between PAHs and other pollutants suggest that a variety of sources and ages of particles are present. Among carbon monoxide, nitrogen oxides (NOx), and carbon dioxide, particulate PAHs are most strongly correlated with NOx. Mexico City's PAH-to-black carbon mass ratio of 0.01 is similar to that found on a freeway loop in the Los Angeles area and approximately 8-30 times higher than that found in other cities. Ratios also indicate that primary combustion particles are rapidly coated by secondary aerosol in Mexico City. If so, the lifetime of PAHs may be prolonged if the coating protects them against photodegradation or heterogeneous reactions.

  20. The need for standards and codes to ensure an acoustically comfortable environment in multifamily housing buildings in Mexico City

    NASA Astrophysics Data System (ADS)

    Kotasek Gonzalez, Eduardo; Rodriguez Manzo, Fausto

    2002-11-01

    It is clear that almost all kinds of buildings require protection against noise and undesirable sounds, however, there are some countries where this is not yet regulated, such is the case of Mexico. Mexico City, the biggest city in the world could also be the noisiest. This is a problem which is today being debated; in fact there is no doubt that this has an important influence on the acoustic comfort conditions of dwellings, besides the habits and culture of the inhabitants, which are very different from those in the Anglo-Saxon countries. These are all details that must be taken into account in the design of an acoustic comfort standard for buildings in cities like Mexico. In this paper we deal with this problem and it suggests some recommendations to consider in a proposed acoustic comfort standard or code to be applied in the design of multifamily housing buildings in Mexico City.

  1. The strong ground motion in Mexico City: array and borehole data analysis.

    NASA Astrophysics Data System (ADS)

    Roullé, A.; Chávez-García, F. J.

    2003-04-01

    Site response at Mexico City has been intensively studied for the last 15 years, since the disastrous 1985 earthquakes. After those events, more than 100 accelerographs were installed, and their data have been extremely useful in quantifying amplification and in the subsequent upgrading of the building code. However, detailed analysis of the wavefield has been hampered by the lack of absolute time in the records and the large spacing between stations in terms of dominant wavelengths. In 2001, thanks to the support of CONACYT, Mexico, a new dense accelerographic network was installed in the lake bed zone of Mexico City. The entire network, including an existing network of 3 surface and 2 borehole stations operated by CENAPRED, consists in 12 surface and 4 borehole stations (at 30, 102 and 50 meters). Each station has a 18 bits recorder and a GPS receiver so that the complete network is a 3D array with absolute time. The main objective of this array is to provide data that can help us to better understand the wavefield that propagates in Mexico City during large earthquakes. Last year, a small event of magnitude 6.0 was partially recorded by 6 of the 12 surface stations and all the borehole stations. We analysed the surface data using different array processing techniques such as f-k methods and MUSIC algorithm and the borehole ones using a cross-correlation method. For periods inferior to the site resonance period, the soft clay layer with very low propagation velocities (less than 500 m/s) and a possible multipathing rule the wavefield pattern. For the large period range, the dominant surface wave comes from the epicentral direction and propagates with a quicker velocity (more than 1500 m/s) that corresponds to the velocity of deep layers. The analysis of borehole data shows the presence of different quick wavetrains in the short period range that could correspond to the first harmonic modes of Rayleigh waves. To complete this study, four others events recorded in

  2. Presence of polycyclic aromatic hydrocarbons (PAHs) in apple in rural terrains from Mexico City.

    PubMed

    Salinas, Rutilio Ortiz; González, Gilberto Díaz; Bermudez, Beatriz Schettino; Tolentino, Rey Gutiérrez; Vega Y León, Salvador

    2010-08-01

    This paper describes PAH concentrations in apple crops that are growing in rural terrains in Mexico City. The concentrations of individual PAHs showed great variability, there being low and high molecular weight compounds in dry (high molecular weight for Tlahuac 7.06 microg/g and Milpa Alta 3.96 microg/g) and wet months (high molecular weight for Tlahuac 11.25 microg/g and Milpa Alta 12.05 microg/g). Some PAHs indicators and cross plot ratios Ant/(Ant + Phe) and Flu/(Flu + Pyr) define fossil fuels and vegetation combustion as the source of contamination over the cuticle of the apples. It is likely that deposition (dry and wet) is the principal source o f contamination over the apple surface. This study reveals the presence of PAHs in apples due to the high air contamination of Mexico City.

  3. Asymmetric correlations in the ozone concentration dynamics of the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Meraz, M.; Alvarez-Ramirez, J.; Echeverria, J. C.

    2017-04-01

    Mexico City is a megalopolis with severe pollution problems caused by vehicles and industrial activity. This condition imposes important risks to human health and economic activity. Based on hourly-sampled data during the last decade, in a recent work (Meraz et al., 2015) we showed that the pollutant dynamics in Mexico City exhibits long-term and scale-dependent persistence effects resulting from the combination of pollutants generation by vehicles and removal by advection mechanisms. In this work, we analyzed the dynamics of ozone, a key component reflecting the degree of atmospheric contamination, to determine if its long-term correlations are asymmetric in relation to the actual concentration trend (increasing or decreasing). The analysis is conducted with detrended fluctuation analysis. The results showed that the average ozone dynamics is uncorrelated when the concentration is increasing. In contrast, the ozone dynamics shows long-term anti-persistence effects when the concentration is decreasing.

  4. An analysis of a low-energy, low-water use community in Mexico City

    NASA Astrophysics Data System (ADS)

    Bermudez Alcocer, Jose Luis

    This study investigated how to determine a potential scenario to reduce energy, water and transportation use in Mexico City by implementing low-energy, low-water use communities. The proposed mixed-use community has multi-family apartments and a small grocery store. The research included the analysis of: case studies, energy simulation, and hand calculations for water, transportation and cost analysis. The previous case studies reviewed include: communities in Mexico City, Mexico, Austin, Texas, Phoenix, Arizona, New York City, New York and San Diego, California in terms of successful low-energy, low-water use projects. The analysis and comparison of these centers showed that the Multifamiliar Miguel Aleman is an excellent candidate to be examined for Mexico City. This technical potential study evaluated energy conserving measures such as low-energy appliances and efficient lighting that could be applied to the apartments in Mexico City to reduce energy-use. The use of the simulations and manual calculations showed that the application of the mixed-use concept was successful in reducing the energy and water use and the corresponding carbon footprint. Finally, this technical potential study showed taking people out of their cars as a result of the presence of the on-site grocery store, small recreation center and park on the ground floor also reduced their overall transportation energy-use. The improvement of the whole community (i.e., apartments plus grocery store) using energy-efficient measures provided a reduction of 70 percent of energy from the base-case. In addition a 69 percent reduction in water-use was achieved by using water-saving fixtures and greywater reuse technologies for the complex. The combination of high-efficiency automobiles and the presence of the on-site grocery store, small recreation center and park potentially reduced the transportation energy-use by 65 percent. The analysis showed an energy cost reduction of 82 percent reduction for

  5. Drinking water quality in a Mexico city university community: perception and preferences.

    PubMed

    Espinosa-García, Ana C; Díaz-Ávalos, Carlos; González-Villarreal, Fernando J; Val-Segura, Rafael; Malvaez-Orozco, Velvet; Mazari-Hiriart, Marisa

    2015-03-01

    A transversal study was conducted at the University City campus of the National Autonomous University of Mexico (UNAM) in Mexico City, with the goal of estimating the university community preference for drinking either tap water or bottled water and the reasons for their selection. A representative sample of three university community subpopulations (students, workers/administrative staff, and academic personnel) were interviewed with respect to their water consumption habits. The results showed that 75% of the university community drinks only bottled water and that the consumption of tap water is low. The interviewees responded that the main reason for this preference is the organoleptic features of tap water independent of quality. In general, the participants in this study do not trust the quality of the tap water, which could be caused by the facilities that distribute bottled water encouraging a general disinterest in learning about the origin and management of the tap water that is distributed on campus.

  6. A Mexico City-Based Immersion Education Program: Training Mental Health Clinicians for Practice with Latino Communities

    ERIC Educational Resources Information Center

    Platt, Jason James

    2012-01-01

    This article describes the philosophical foundations and educational methods of a Spanish language and cultural immersion program based in Mexico City, Mexico. The program is designed to assist U.S. graduate students in marriage and family therapy and clinical psychology programs to improve clinical service delivery with Latino clients. Utilizing…

  7. The avoidable health effects of air pollution in three Latin American cities: Santiago, São Paulo, and Mexico City.

    PubMed

    Bell, Michelle L; Davis, Devra L; Gouveia, Nelson; Borja-Aburto, Víctor H; Cifuentes, Luis A

    2006-03-01

    Urban centers in Latin American often face high levels of air pollution as a result of economic and industrial growth. Decisions with regard to industry, transportation, and development will affect air pollution and health both in the short term and in the far future through climate change. We investigated the pollution health consequences of modest changes in fossil fuel use for three case study cities in Latin American: Mexico City, Mexico; Santiago, Chile; and São Paulo, Brazil. Annual levels of ozone and particulate matter were estimated from 2000 to 2020 for two emissions scenarios: (1) business-as-usual based on current emissions patterns and regulatory trends and (2) a control policy aimed at lowering air pollution emissions. The resulting air pollution levels were linked to health endpoints through concentration-response functions derived from epidemiological studies, using local studies where available. Results indicate that the air pollution control policy would have vast health benefits for each of the three cities, averting numerous adverse health outcomes including over 156,000 deaths, 4 million asthma attacks, 300,000 children's medical visits, and almost 48,000 cases of chronic bronchitis in the three cities over the 20-year period. The economic value of the avoided health impacts is roughly 21 to 165 billion Dollars (US). Sensitivity analysis shows that the control policy yields significant health and economic benefits even with relaxed assumptions with regard to population growth, pollutant concentrations for the control policy, concentration-response functions, and economic value of health outcomes. This research demonstrates the health and economic burden from air pollution in Latin American urban centers and the magnitude of health benefits from control policies.

  8. The chemo and the mona: inhalants, devotion and street youth in Mexico City.

    PubMed

    Gigengack, Roy

    2014-01-01

    This paper understands inhalant use--the deliberate inhalation of volatile solvents or glues with intentions of intoxication--as a socially and culturally constituted practice. It describes the inhalant use of young street people in Mexico City from their perspective ("the vicioso or inhalant fiend's point of view"). Even if inhalant use is globally associated with economic inequality and deprivation, there is a marked lack of ethnography. Incomprehension and indignation have blocked our understanding of inhalant use as a form of marginalised drug use. The current explanation models reduce inhalant consumption to universal factors and individual motives; separating the practice from its context, these models tend to overlook gustatory meanings and experiences. The paper is informed by long-term, on-going fieldwork with young street people in Mexico City. Fieldwork was done from 1990 through 2010, in regular periods of fieldwork and shorter visits, often with Mexican colleagues. We created extensive sets of fieldnotes, which were read and re-read. "Normalcy" is a striking feature of inhalant use in Mexico City. Street-wise inhabitants of popular neighbourhoods have knowledge about inhalants and inhalant users, and act accordingly. Subsequently, Mexico City's elaborate street culture of sniffing is discussed, that is, the range of inhalants used, how users classify the substances, and their techniques for sniffing. The paper also distinguishes three patterns of inhalant use, which more or less correlate with age. These patterns indicate embodiments of street culture: the formation within users of gusto, that is, an acquired appetite for inhalants, and of vicio, the inhalant fiends' devotion to inhalants. What emerges from the ethnographic findings is an elaborate street culture of sniffing, a complex configuration of shared perspectives and embodied practices, which are shaped by and shaping social exclusion. These findings are relevant to appreciate and address the

  9. Vertical Profile Measurements of Volatile Organic Compounds in Southwest Mexico City with a semiautomatic sampling system

    NASA Astrophysics Data System (ADS)

    Solano-Murillo, M.; Torres-Jardón, R.; Gutiérrez-López, W.; García-Espinosa, M.

    2017-12-01

    A prototype for the simultaneous sampling of VOC at different heights using a Tethered meteorological balloon was integrated and tested in a smog urban receptor site in southwest Mexico City. A selection of COV species measured at three different heights was used to estimate the chemical aging using the expression:Δt=[ln(ER1,2)-ln(VOC1/VOC2)]/[(K1-K2)[OH

  10. Environmental implications on the oxygenation of gasoline with ethanol in the metropolitan area of Mexico City.

    PubMed

    Schifter, I; Vera, M; Díaz, L; Guzmán, E; Ramos, F; López-Salinas, E

    2001-05-15

    Motor vehicle emission tests were performed on 12 in-use light duty vehicles, made up of the most representative emission control technologies in Mexico City: no catalyst, oxidative catalyst, and three way catalyst. Exhaust regulated (CO, NOx, and hydrocarbons) and toxic (benzene, formaldehyde, acetaldehyde, and 1,3-butadiene) emissions were evaluated for MTBE (5 vol %)- and ethanol (3, 6, and 10 vol %)-gasoline blends. The most significant overall emissions variations derived from the use of 6 vol % ethanol (relative to a 5% MTBE base gasoline) were 16% decrease in CO, 28% reduction in formaldehyde, and 80% increase in acetaldehyde emissions. A 26% reduction in CO emissions from the oldest fleet (< MY 1991, without catalytic converter), which represents about 44% of the in-use light duty vehicles in Mexico city, can be attained when using 6 vol% ethanol-gasoline, without significant variation in hydrocarbons and NOx emissions, when compared with a 5% vol MTBE-gasoline. On the basis of the emissions results, an estimation of the change in the motor vehicle emissions of the metropolitan area of Mexico city was calculated for the year 2010 if ethanol were to be used instead of MTBE, and the outcome was a considerable decrease in all regulated and toxic emissions, despite the growing motor vehicle population.

  11. Porcine circovirus type 2 antibody detection in backyard pigs from Mexico City.

    PubMed

    Ramírez-Mendoza, H; Martínez, C; Mercado, C; Castillo-Juárez, H; Hernández, J; Segalés, J

    2007-08-01

    PCV2 antibodies have been found in pigs from all continents. However, this finding has been mainly studied in domestic swine reared under intensive production conditions. Mexico City, with a human population over 19 million in 2005, has both urban and rural areas. The pig production in its rural area is based on small family backyard farms. Taking into account this rather unique form of rearing pigs, the objective of this study was to determine the seroprevalence in backyard pigs from the rural area of Mexico City. A total of 695 backyard pig serum samples from 108 small family farms belonging to seven municipal areas were studied by immunoperoxidase monolayer assay technique. One hundred six out of the 108 family farms (98.14%) had at least one positive serum sample. On the other hand, 136 (19.57%), 264 (37.99%) and 248 (34.82%) pigs had low, intermediate and high titres to PCV2, respectively. Only 53 samples (7.63%) were negative for PCV2 antibodies. No apparent differences in antibody titre groups were observed among backyard pigs from the different municipal areas. In conclusion, the present study, the first one performed in this kind of extensively produced pigs, indicates that PCV2 is ubiquitous in backyard pigs from Mexico City.

  12. [Diabetes mellitus within low socioeconomic strata in Mexico City: a relevant problem].

    PubMed

    Avila-Curiel, Abelardo; Shamah-Levy, Teresa; Galindo-Gómez, Carlos; Cuevas-Nasu, Lucia; Moreno-Macias, Hortensia; Chávez-Villasana, Adolfo

    2007-01-01

    To evaluate the feeding and nutrition conditions and its relation with diabetes mellitus (DM-2) in adult population (> 30 years) a sample belonging to the low socioeconomic stratum of the Mexico City metropolitan area was studied. They were participants in the Second Feeding and Nutrition Survey in the Mexico City metropolitan area. (ENURBAL-2002). Information collected by the ENURBAL 2002 was used in order to evaluate the relationship between some risk factors and diabetes mellitus in adult population of low economical level. Logistical regression analysis was applied. A complete set of 1279 individuals with ages over 30 years was studied. The 9.9% (IC 95% 7.9, 12.4) had been previously diagnosed as diabetics and 3.9% (IC 95% 2.9, 5.4) were not been diagnosed but their glycemia reached diabetic levels. Total diabetes prevalence observed in this study was 13.8% (IC 95% 11.7, 16.3). People with good score on its knowledge about nutrition, as well as high total fat intake, are significant and positively associated with DM-2 (RM = 2.41, IC 95% 1.09, 5.35 and RM = 2.14 IC 95% 1.24, 3.69, respectively). Diabetes mellitus was highly prevalent among adult (> 30 years population) mainly on the lower socioeconomic stratum of Mexico City. This result is important to promote changes in life style that allow to prevent its appearance by modifying the obesigenic environment and changes in the feeding patterns.

  13. Co-control of urban air pollutants and greenhouse gases in Mexico City.

    PubMed

    West, J Jason; Osnaya, Patricia; Laguna, Israel; Martínez, Julia; Fernández, Adrián

    2004-07-01

    This study addresses the synergies of mitigation measures to control urban air pollutant and greenhouse gas (GHG) emissions, in developing integrated "co-control" strategies for Mexico City. First, existing studies of emissions reduction measures--PROAIRE (the air quality plan for Mexico City) and separate GHG studies--are used to construct a harmonized database of options. Second, linear programming (LP) is developed and applied as a decision-support tool to analyze least-cost strategies for meeting co-control targets for multiple pollutants. We estimate that implementing PROAIRE measures as planned will reduce 3.1% of the 2010 metropolitan CO2 emissions, in addition to substantial local air pollutant reductions. Applying the LP, PROAIRE emissions reductions can be met at a 20% lower cost, using only the PROAIRE measures, by adjusting investments toward the more cost-effective measures; lower net costs are possible by including cost-saving GHG mitigation measures, but with increased investment. When CO2 emission reduction targets are added to PROAIRE targets, the most cost-effective solutions use PROAIRE measures for the majority of local pollutant reductions, and GHG measures for additional CO2 control. Because of synergies, the integrated planning of urban-global co-control can be beneficial, but we estimate that for Mexico City these benefits are often small.

  14. Aerosol Light Absorption and Scattering in Mexico City: Comparison With Las Vegas, NV, and Los Angeles, CA.

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.; Campbell, D.; Fujita, E.

    2007-12-01

    Aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The primary site in Mexico City was an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). Similar campaigns were held in Las Vegas, NV in January-February, 2003; and Los Angeles, CA at numerous sites during all seasons from 2003 through 2007. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The photoacoustic instrument (PAS) used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In Mexico City the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of Mexico City resulted in more direct solar radiation. Further insight on the meteorological connections and population dynamics will be discussed.

  15. Final Opportunity to Rehabilitate an Urban River as a Water Source for Mexico City

    PubMed Central

    Mazari-Hiriart, Marisa; Pérez-Ortiz, Gustavo; Orta-Ledesma, María Teresa; Armas-Vargas, Felipe; Tapia, Marco A.; Solano-Ortiz, Rosa; Silva, Miguel A.; Yañez-Noguez, Isaura; López-Vidal, Yolanda; Díaz-Ávalos, Carlos

    2014-01-01

    The aim of this study was to evaluate the amount and quality of water in the Magdalena-Eslava river system and to propose alternatives for sustainable water use. The system is the last urban river in the vicinity of Mexico City that supplies surface water to the urban area. Historical flow data were analyzed (1973–2010), along with the physicochemical and bacteriological attributes, documenting the evolution of these variables over the course of five years (2008–2012) in both dry and rainy seasons. The analyses show that the flow regime has been significantly altered. The physicochemical variables show significant differences between the natural area, where the river originates, and the urban area, where the river receives untreated wastewater. Nutrient and conductivity concentrations in the river were equivalent to domestic wastewater. Fecal pollution indicators and various pathogens were present in elevated densities, demonstrating a threat to the population living near the river. Estimates of the value of the water lost as a result of mixing clean and contaminated water are presented. This urban river should be rehabilitated as a sustainability practice, and if possible, these efforts should be replicated in other areas. Because of the public health issues and in view of the population exposure where the river flows through the city, the river should be improved aesthetically and should be treated to allow its ecosystem services to recover. This river represents an iconic case for Mexico City because it connects the natural and urban areas in a socio-ecological system that can potentially provide clean water for human consumption. Contaminated water could be treated and reused for irrigation in one of the green areas of the city. Wastewater treatment plants and the operation of the existing purification plants are urgent priorities that could lead to better, more sustainable water use practices in Mexico City. PMID:25054805

  16. Final opportunity to rehabilitate an urban river as a water source for Mexico City.

    PubMed

    Mazari-Hiriart, Marisa; Pérez-Ortiz, Gustavo; Orta-Ledesma, María Teresa; Armas-Vargas, Felipe; Tapia, Marco A; Solano-Ortiz, Rosa; Silva, Miguel A; Yañez-Noguez, Isaura; López-Vidal, Yolanda; Díaz-Ávalos, Carlos

    2014-01-01

    The aim of this study was to evaluate the amount and quality of water in the Magdalena-Eslava river system and to propose alternatives for sustainable water use. The system is the last urban river in the vicinity of Mexico City that supplies surface water to the urban area. Historical flow data were analyzed (1973-2010), along with the physicochemical and bacteriological attributes, documenting the evolution of these variables over the course of five years (2008-2012) in both dry and rainy seasons. The analyses show that the flow regime has been significantly altered. The physicochemical variables show significant differences between the natural area, where the river originates, and the urban area, where the river receives untreated wastewater. Nutrient and conductivity concentrations in the river were equivalent to domestic wastewater. Fecal pollution indicators and various pathogens were present in elevated densities, demonstrating a threat to the population living near the river. Estimates of the value of the water lost as a result of mixing clean and contaminated water are presented. This urban river should be rehabilitated as a sustainability practice, and if possible, these efforts should be replicated in other areas. Because of the public health issues and in view of the population exposure where the river flows through the city, the river should be improved aesthetically and should be treated to allow its ecosystem services to recover. This river represents an iconic case for Mexico City because it connects the natural and urban areas in a socio-ecological system that can potentially provide clean water for human consumption. Contaminated water could be treated and reused for irrigation in one of the green areas of the city. Wastewater treatment plants and the operation of the existing purification plants are urgent priorities that could lead to better, more sustainable water use practices in Mexico City.

  17. Seismic fragility formulations for segmented buried pipeline systems including the impact of differential ground subsidence

    SciTech Connect

    Pineda Porras, Omar Andrey; Ordaz, Mario

    2009-01-01

    Though Differential Ground Subsidence (DGS) impacts the seismic response of segmented buried pipelines augmenting their vulnerability, fragility formulations to estimate repair rates under such condition are not available in the literature. Physical models to estimate pipeline seismic damage considering other cases of permanent ground subsidence (e.g. faulting, tectonic uplift, liquefaction, and landslides) have been extensively reported, not being the case of DGS. The refinement of the study of two important phenomena in Mexico City - the 1985 Michoacan earthquake scenario and the sinking of the city due to ground subsidence - has contributed to the analysis of the interrelation ofmore » pipeline damage, ground motion intensity, and DGS; from the analysis of the 48-inch pipeline network of the Mexico City's Water System, fragility formulations for segmented buried pipeline systems for two DGS levels are proposed. The novel parameter PGV{sup 2}/PGA, being PGV peak ground velocity and PGA peak ground acceleration, has been used as seismic parameter in these formulations, since it has shown better correlation to pipeline damage than PGV alone according to previous studies. By comparing the proposed fragilities, it is concluded that a change in the DGS level (from Low-Medium to High) could increase the pipeline repair rates (number of repairs per kilometer) by factors ranging from 1.3 to 2.0; being the higher the seismic intensity the lower the factor.« less

  18. Effect of liquefied petroleum gas on ozone formation in Guadalajara and Mexico City.

    PubMed

    Jaimes-López, J Luis; Sandoval-Fernández, Julio; González-Ortíz, Emmanuel; Vázquez-García, Marcos; González-Macías, Uriel; Zambrano-García, Angel

    2005-06-01

    Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O3) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O3 was monitored in each city for 20 days (8:00 a.m.-6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). Tested additions of both components were 35% (by volume) in GMA and 60% (by volume) in MCMA. The addition effects on O3 (max) were compared with effects from diluting LPG components or total nonmethane hydrocarbons (tNMHCs) by 50%. Diluting tNMHCs had the greatest absolute effect at both cities: it lowered O3 (max) by 24% in GMA and 55% in MCMA. Adding commercial LPG increased O3 (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O3 (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O3 (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O3 formation to a lesser extent than estimated previously.

  19. Vulnerability to heat-related mortality in Latin America: a case-crossover study in São Paulo, Brazil, Santiago, Chile and Mexico City, Mexico

    PubMed Central

    Bell, Michelle L; O’Neill, Marie S; Ranjit, Nalini; Borja-Aburto, Victor H; Cifuentes, Luis A; Gouveia, Nelson C

    2008-01-01

    Background Factors affecting vulnerability to heat-related mortality are not well understood. Identifying susceptible populations is of particular importance given anticipated rising temperatures from climatic change. Methods We investigated heat-related mortality for three Latin American cities (Mexico City, Mexico; São Paulo, Brazil; Santiago, Chile) using a case-crossover approach for 754 291 deaths from 1998 to 2002. We considered lagged exposures, confounding by air pollution, cause of death and susceptibilities by educational attainment, age and sex. Results Same and previous day apparent temperature were most strongly associated with mortality risk. Effect estimates remained positive though lowered after adjustment for ozone or PM10. Susceptibility increased with age in all cities. The increase in mortality risk for those ≥65 comparing the 95th and 75th percentiles of same-day apparent temperature was 2.69% (95% CI: −2.06 to 7.88%) for Santiago, 6.51% (95% CI: 3.57–9.52%) for São Paulo and 3.22% (95% CI: 0.93–5.57%) for Mexico City. Patterns of vulnerability by education and sex differed across communities. Effect estimates were higher for women than men in Mexico City, and higher for men elsewhere, although results by sex were not appreciably different for any city. In São Paulo, those with less education were more susceptible, whereas no distinct patterns by education were observed in the other cities. Conclusions Elevated temperatures are associated with mortality risk in these Latin American cities, with the strongest associations in São Paulo, the hottest city. The elderly are an important population for targeted prevention measures, but vulnerability by sex and education differed by city. PMID:18511489

  20. Land subsidence

    USGS Publications Warehouse

    Holzer, T.L.

    1986-01-01

    In November 1966, sixty percent of Venice, Italy, is inundated by a storm surge that causes waters in the Venetian lagoon to rise more than 6 feet. On December 28, 1971, a janitor at the Washington Elementary School in Johnston City, Illinois, discovers sever cracking of the school. In January 1972, the school is abandoned and subsequently razed. In the 1970's, five homes in New Orleans, Louisiana, are destroyed by gas explosins. In May 198, a 350 feet diameter sink-hole forms in a business area in Winter Park, Florida, and swallows a home and parts of several businesses. In August 1983, Hurricane Alicia slams into the texas Gulf Coast near Houston, Texas, and devastates the 500 home Brownwood subdivision on the north end of Galveston Bay. Homes are torn from their foundations and reduced to rubble. 

  1. [Interepidemic transmission of dengue in the city of Colima, Mexico].

    PubMed

    Espinoza-Gómez, Francisco; Hernández-Suárez, Carlos Moisés; Rendón-Ramírez, Ruth; Carrillo-Alvarez, Mayra Lizet; Flores-González, Juan Carlos

    2003-01-01

    To determine the occurrence of interepidemic dengue in a community infested with Aedes aegypti and to analyze its epidemiologic characteristics. A longitudinal probabilistic study was carried out in Colima City between 2001 and 2002. The sample population consisted of 245 subjects. The following were recorded for each subject: sex, age, socio-economic level and dengue fever symptoms, testing for serum IgG and IgM antidengue, using quick immunochromatography as well as ELISA tests, in a seven-month follow-up period. Twelve individuals showed recent dengue infection (incidence: 1.77%; 95%: confidence interval 0.9-3.1%). Of these, eight had recent clinical symptoms (chi 2 = 19.6; p < 0.0001, odss ratio 19.6). Poisson regression analysis showed no evidence of correlation between recent infection and sex, age, or socioeconomic level. Communities infested with A. aegypti, like Colima, may continually exhibit dengue infection with no apparent epidemic. Such infections are seemingly not associated with age, sex, or socioeconomic level, but with clinical symptoms. This situation could be considered an early indicator of interepidemic transmission.

  2. VOC Monitoring to Understand Changes in Secondary Pollution in Mexico City

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Jaimes-Palomera, M.; Retama, A.; Neria, A.; Rivera, O.; Elias, G.

    2015-12-01

    Previous studies have documented the distribution, diurnal pattern, magnitude, and reactivity of the volatile organic compounds (VOCs) within and downwind of Mexico City. These studies have provided valuable data, but their duration has been restricted to a few weeks since the majority have been part of intensive field campaigns. With the aim of addressing the VOC pollution problem during longer monitoring periods and evaluating control measures to reduce the production of ozone and secondary aerosols, the environmental authorities of Mexico City through its Air Quality Monitoring Network have developed a program to monitor over 50 VOC species every hour in selected existing air quality monitoring stations inside and outside the urban sprawl. The program started with a testing period of six months in 2012 covering the ozone-season (Mar-May). Results of this first campaign are presented in this paper. Using as reference VOC data collected in 2003, reductions in the mixing ratios of light alkanes associated with the consumption of liquefied petroleum gas and aromatic compounds related with the evaporation of fossil fuels and solvents were observed. In contrast, a clear increase in the mixing ratio of olefins was observed. This increase is of relevance to understand the moderate success in the reduction of ozone and fine aerosols in recent years in comparison to other criteria pollutants, which have substantially decreased. Particular features of the diurnal profiles, reactivity with the hydroxyl radical and correlations between individual VOCs and carbon monoxide are used to investigate the influence of specific emission sources. The results discussed here expect to highlight the importance of monitoring VOCs to better understand the drivers and impacts of secondary pollution in large cities like Mexico City.

  3. The traffic crisis and a tale of two cities: Traffic and air quality in Bangkok and Mexico City

    SciTech Connect

    Pendakur, V.S.; Badami, M.G.

    1995-12-31

    This paper focuses on congestion management techniques, traffic congestion levels and air quality. By using data from Bangkok and Mexico City, it illustrates the need for drastic changes in transportation policy tools and techniques for congestion management and for improving environmental quality. New approaches to investment and regulatory policy analysis and implementation are suggested. This requires the inclusion of all costs and benefits (economic and ecological) in the policy matrix so that investment and regulatory policies act in unison. Megacities are dominant in social, political and economic terms. 30 to 60% of national GDP is typically produced in these cities.more » Their human and motor vehicle populations have been doubling every 15-20 and 6-10 years respectively. They also have the most severe traffic congestion and air quality problems. They have the nation`s highest incidence of poverty and absolute poverty. Large portions of their populations endure severely unhealthy housing and sanitation conditions. Following are important characteristics of urban transportation systems in the megacities: the city centres are heavily congested with motorized traffic; traffic crawl rates vary from 2 to 10 km/hr; car and motorcycle ownership are increasing at annual rates of 10-12% and 15-20% respectively; significant air pollution with no relief in sight; TDM strategies are primarily creating new supply of road capacity; fairly high transit trips with substantial transit investments; weak air pollution monitoring and enforcement; and fairly cheap fuel and high costs of vehicles.« less

  4. Two new synanthropic species of Anyphaena Sundevall (Araneae: Anyphaenidae) associated to houses in Mexico City.

    PubMed

    Durán-Barrón, César G; Pérez, Tila M; Brescovit, Antonio D

    2016-04-12

    The family Anyphaenidae is composed by 56 genera and 542 species worldwide (World Spider Catalog 2015). These spiders, known as "ghost spiders", are wandering hunters living in a variety of environments, from forests to deserts, and can be quite abundant in different crops such as cotton, sorghum and rice (Brescovit 1996; Young & Edwards 1990; Taylor & Pfannenstiel 2008). They typically live on vegetation, among dead leaves or under loose bark and rocks (Richman & Ubick 2005) but synanthropic associations have been reported for a few species (Jiménez 1998; Guarisco 1999; Durán-Barrón et al. 2009). The genus Anyphaena has 81 species widely distributed in Asia, Central Europe, North America and Mexico (Brescovit 1996; Richman & Ubick 2005; World Spider Catalog 2015). The species from Noth America and Mexico were revised by Platnick (1974) who recognized four species groups (accentuata, celer, pectorosa and pacifica). Platnick (1977), Platnick & Lau (1975) and Brescovit & Lise (1989) complemented the revision of the genus in Central America. Presently, there are 27 species of Anyphaena recorded in Mexico (World Spider Catalog 2015), 24 of them from the celer group. Here, two new species of Anyphaena are described based in material collected during an inventory of spiders associated to houses in Mexico City, carried out by Durán-Barrón et al. (2009). Both species have the diagnostic characters of the members of the pacifica group as defined by Platnick (1974), such as the lack of leg coxal spurs and the presence of a lightly sclerotized atrium in the female epigynum. These species represent the first record of the pacifica group in Mexico. The occurrence of Anyphaenidae associated to houses was reported in Mexico by Durán-Barrón et al. (2009), who recorded Anyphaena obregon Platnick & Lau, 1975 and Hibana futilis (Banks, 1898) as frequent inhabitants inside houses. The species herein described are reported solely from urban areas and can be also characterized as

  5. Impact of wildfires on the air quality of Mexico City, 1992-1999.

    PubMed

    Bravo, A H; Sosa, E R; Sánchez, A P; Jaimes, P M; Saavedra, R M I

    2002-01-01

    Wildfires in Mexico increased in 1998, compared to information for the last 6 years. The average number of wildfires in the Mexico City Metropolitan Area (MCMA) for this year (1998) were 58% (1916 events) more events than the 1992-1997 (average cases 1217 events). Mexico City affected area corresponds to 1.3% of the national affected area. The purpose of this paper is to evaluate the impact on the particles air quality due to the wildfire emissions at the MCMA and surrounding areas. Using the corresponding US EPA emission factors for wildfires, the tons of particulate matter, nitrogen oxides, carbon monoxide, and total hydrocarbons emitted by this source for the MCMA case were obtained. The calculated emissions during wildfires were correlated with the levels of particles present in the atmosphere. A comparison of the concentration levels of particles, both as PM10 as well as TSP, were made for the years 1992-1998, during wet and dry season, being March, April, and May the critical months due to the presence of wildfires. A good correlation is observed between particulate wildfire emissions and particulate air quality, being stronger for TSP. A clear impact on the particles air quality due to the increase of wildfires in 1998, is observed when this year is compared with 1997, presenting an increment of 200-300% for some monitoring stations.

  6. An indoor radon survey of the X-ray rooms of Mexico City hospitals

    SciTech Connect

    Juarez, Faustino; Reyes, Pedro G.; Espinosa, Guillermo

    This paper presents the results of measurements of indoor radon concentrations in the X-ray rooms of a selection of hospitals in the metropolitan area of Mexico City. The metropolitan area of Mexico City is Mexico's largest metropolitan area by population; the number of patients requiring the use of X-rays is also the highest. An understanding of indoor radon concentrations in X-ray rooms is necessary for the estimation of the radiological risk to which patients, radiologists and medical technicians are exposed. The indoor radon concentrations were monitored for a period of six months using nuclear track detectors (NTD) consisting of amore » closed-end cup system with CR-39 (Lantrack Registered-Sign ) polycarbonate as detector material. The indoor radon concentrations were found to be between 75 and 170 Bq m{sup -3}, below the USEPA-recommended indoor radon action level for working places of 400 Bq m{sup -3}. It is hoped that the results of this study will contribute to the establishment of recommended action levels by the Mexican regulatory authorities responsible for nuclear safety.« less

  7. Frequency of functional bowel disorders among healthy volunteers in Mexico City.

    PubMed

    Schmulson, Max; Ortíz, Orianna; Santiago-Lomeli, Mariana; Gutiérrez-Reyes, Gabriela; Gutiérrez-Ruiz, María Concepción; Robles-Díaz, Guillermo; Morgan, Douglas

    2006-01-01

    The frequency of functional bowel disorders (FBD) in Mexico using the Rome II criteria is unknown. The Rome II Modular Questionnaire (RII-MQ) was translated into Spanish in coordination with the Rome Committee and their Latin American program. Volunteers were recruited by advertisement in Mexico City, and administered the RII-MQ. The study population consisted of 324 healthy volunteers, with a mean age of 35.7; 66% were female. The most prevalent disorders were heartburn 35%, irritable bowel syndrome (IBS) 35%, functional bloating 21%, proctalgia fugax 21%, and functional constipation 19%. Based on gender, IBS-C was 4 times more frequent in females than males (19 vs. 4.6%) and functional bloating 3 times more frequent (10 vs. 3.7%). Differences according to occupation included a higher prevalence of ulcer-like dyspepsia (p = 0.04), IBS-C (p = 0.018) and proctalgia fugax (p = 0.034) among students. This is the first study to use RII-MQ to determine the prevalence of FBD in urban Mexico. The prevalence of IBS was significant and is related to a number of factors, including the stress of living in an overpopulated city. Selection bias is likely operative. A community-based study is warranted. Copyright 2006 S. Karger AG, Basel

  8. From Reproductive Rights to Responsibilization: Fashioning Liberal Subjects in Mexico City's New Public Sector Abortion Program.

    PubMed

    Singer, Elyse Ona

    2017-12-01

    Building on medical anthropology literature that analyzes doctor-patient interactions as a charged site for the production of political subjectivities, I demonstrate how a central feature of Mexico City's new public sector abortion program involves "responsibilization." In accordance with entrenched Ministry of Health objectives, providers transmit a suite of values about personal responsibility and self-regulation through the use of birth control, hinging abortion rights to responsible reproductive subjectivity. Based on 18 months of ethnographic research across program clinics, including 75 interviews with patients and providers, I show how interrupción legal del embarazo protocols fashion "responsibilized" liberal subjects. I argue that the recent granting of abortion rights in Mexico City-ostensibly a new moment for the construction of women's citizenship-instead reflects and extends long-standing state agendas of "reproductive governance." My analysis of reproductive rights as the newest framing of ongoing population policies in Mexico adds to a critical anthropology of human rights and of liberal projects of governance. © 2016 by the American Anthropological Association.

  9. Clinical experience and practical skills: results from Mexico City's paramedic registry.

    PubMed

    Peralta, Luis M Pinet; Fraga, Juan M; Asensio, Enrique

    2008-01-01

    Trauma is a leading cause of death and disability in Mexico. Unintentional injuries, along with diabetes and heart disease, contribute to > 35% of the country's total mortality. Effective and efficient prehospital care of the conditions may improve outcomes. The objective of this paper was to determine if prehospital field experience (PFE) correlated with higher passing rates among candidates for the paramedic registry in Mexico City. This was a retrospective, cohort study using data from the Voluntary Registry of Prehospital Care Professionals (VRPHP) in Mexico City. The mean value for candidate age was 30.6 years and mean value for the years of PFE was 6.8 years (CI = 9-13 years). Most of the applicants were male and almost 90% were basic emergency medical services providers. Sixty-five percent of the candidates were from private, non-profit organizations, 73% were volunteers, and 19% had obtained a university degree. More than 57% had > 5 years of PFE, but the experience level did not correlate significantly with higher passing rates for the registry evaluation (chi2 = 1.66, p = 0.43). The results differed between the two years that the examination was offered (chi2 = 32.98, df = 1, p < 0.001, gamma = 0.54), regardless of gender, education, and years of experience. Previous field experience showed no correlation with passing rates, although the correlations improved between examination periods. The results may be used to support appropriate implementation of future health policies for prehospital emergency services.

  10. The role of health system factors in delaying final diagnosis and treatment of breast cancer in Mexico City, Mexico.

    PubMed

    Bright, Kristin; Barghash, Maya; Donach, Martin; de la Barrera, Marcos Gutiérrez; Schneider, Robert J; Formenti, Silvia C

    2011-04-01

    In Mexico, breast cancer is the leading cancer-related death among women and most cases are diagnosed at advanced stages (50-60%). We hypothesized health system factors could be partly responsible for this delay and performed a prospective review of 166 new breast cases at a major public hospital in Mexico City. Our analysis confirmed the prevalence of locally advanced and metastatic disease (47% of patients). A subset analysis of 32 women with confirmed stage I-IIIC breast cancer found an average time interval of 1.8 months from symptom onset to first primary care consultation (PCC), with an additional 6.6 months from first PCC to confirmed diagnosis, and 0.6 months from diagnosis to treatment initiation. Patients underwent an average of 7.9 clinic visits before confirmed diagnosis. Findings suggest that protracted referral time from primary to specialty care accounts for the bulk of delay, with earlier stage patients experiencing longer delays. These findings reveal a critical need for further study and exploration of interventions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Seasonal variations of rotifers from a high altitude urban shallow water body, La Cantera Oriente (Mexico City, Mexico)

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Sergio González; Sarma, S. S. S.; Nandini, S.

    2017-11-01

    La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City (Mexico). In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico-chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. B rachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca (Schmarda, 1859) and Keratella cochlearis (Gosse, 1851) were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadella patella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll- a. The trophic status of the lake was eutrophic based on Chl- a content but oligotrophic with relation to the Brachionus: Trichocerca ratio.

  12. Evaluating the anthropogenic impacts on fluvial flood risks in a coastal mega-city during its transitional economy (1979-2009): the interaction between land subsidence, urbanization and structural measures

    NASA Astrophysics Data System (ADS)

    Yu, Dapeng; Yin, Jie

    2014-05-01

    Flood risk in a specific geographical location is a function of the interaction between various natural (e.g. rainfall, sea-level rise) and anthropogenic processes (e.g. land subsidence and urbanization). These processes, whether a driver or an alleviating factor, often encompass a large degree of spatial and temporal variability. Looking at a specific process in isolation is likely to provide an incomplete picture of the risks. This paper describes a novel approach to the evaluation of anthropogenic impacts on flood risks in coastal mega-cities by incorporating three anthropogenic variables (land subsidence, urbanization and flood defence) within a scenario-based framework where numerical modelling was undertaken to quantify the risks. The evolving risks at four time points (1979, 1990, 2000 and 2009) were assessed for the Huangpu River floodplain where the City of Shanghai is located. Distributed data of land subsidence rate, urbanization rate and flood defence heights were obtained. Scenarios were designed by representing the rate of land subsidence and flood defence height through the modification of DEM. Effect of urbanization is represented by a roughness parameter in the model simulations. A 2D hydrodynamic model (FloodMap-Inertial) was used to estimate the flood risks associated with each scenario. Flood events with various return periods (10-, 100- and 1000-year) were designed based on a one in 50 year flood event occurred in Shanghai in August 1997. Results demonstrate the individual as well as the combined impacts of the three anthropogenic factors on the changing fluvial flood risks in the Huangpu River basin over the last three decades during the city's transitional economy (1979-2009). Land subsidence and urbanization were found to lead to proportionate but non-linear impact on flood risks due to their complex spatial and temporal interaction. The impacts and their sensitivity are the function of the rate & spatial distribution of each evolving factor

  13. Histopathologic changes of the nasal mucosa in southwest Metropolitan Mexico City inhabitants.

    PubMed Central

    Calderon-Garcidueñas, L.; Osorno-Velazquez, A.; Bravo-Alvarez, H.; Delgado-Chavez, R.; Barrios-Marquez, R.

    1992-01-01

    Metropolitan Mexico City (MMC) is one of the most polluted urban areas in the world. The authors characterized the morphologic nasal mucosal changes in short-term (less than 30 days) and long-term (more than 60 days) exposures to the polluted southwest MMC atmosphere with high levels of ozone and other contaminants versus a control group of subjects living in a nonpolluted, low-ozone Mexican port. Seventy-six inferior turbinate biopsies were examined. The control group showed normal mucociliary epithelium, whereas the short-exposure group displayed loss of normal epithelium, basal cell hyperplasia, and mild dysplasia (17.64%). In the long-term exposure group, 78.72% of dysplasias were found (59.45% mild and 40.54% moderate) together with severe loss of normal respiratory epithelium, prominent basal cell hyperplasia, squamous metaplasia, and submucosal vascular proliferation. Our findings suggest that southwest metropolitan Mexico City inhabitants develop histopathologic changes in their nasal mucosa on exposure to the polluted city atmosphere. Images Figure 5 Figure 6 Figure 7 PMID:1731527

  14. Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City.

    PubMed

    Davis, Lucas W

    2017-02-02

    Policymakers around the world are turning to license-plate based driving restrictions in an effort to address urban air pollution. The format differs across cities, but most programs restrict driving once or twice a week during weekdays. This paper focuses on Mexico City, home to one of the oldest and best-known driving restriction policies. For almost two decades Mexico City's driving restrictions applied during weekdays only. This changed recently, however, when the program was expanded to include Saturdays. This paper uses hourly data from pollution monitoring stations to measure the effect of the Saturday expansion on air quality. Overall, there is little evidence that the program expansion improved air quality. Across eight major pollutants, the program expansion had virtually no discernible effect on pollution levels. These disappointing results stand in sharp contrast to estimates made before the expansion which predicted a 15%+ decrease in vehicle emissions on Saturdays. To understand why the program has been less effective than expected, the paper then turns to evidence from subway, bus, and light rail ridership, finding no evidence that the expansion was successful in getting drivers to switch to lower-emitting forms of transportation.

  15. The IMADA-AVER Boundary Layer Experiment in the Mexico City Area.

    NASA Astrophysics Data System (ADS)

    Doran, J. C.; Bian, X.; de Wekker, S. F. J.; Edgerton, S.; Fast, J. D.; Hubbe, J. M.; Shaw, W. J.; Whiteman, C. D.; Abbott, S.; King, C.; Leach, J.; Mulhearn, M.; Russell, C.; Templeman, B.; Wolfe, D.; Archuleta, J.; Elliott, S.; Fernandez, A.; Langley, D.; Lee, J. T.; Porch, W.; Tellier, L.; Chow, J.; Watson, J. G.; Coulter, R. L.; Martin, T. J.; Shannon, J. D.; White, R.; Martinez, D.; Martinez, J. L.; Mora, V.; Sosa, G.; Mercado, G.; Pena, J. L.; Salas, R.; Petty, R.

    1998-11-01

    A boundary layer field experiment in the Mexico City basin during the period 24 February-22 March 1997 is described. A total of six sites were instrumented. At four of the sites, 915-MHz radar wind profilers were deployed and radiosondes were released five times per day. Two of these sites also had sodars collocated with the profilers. Radiosondes were released twice per day at a fifth site to the south of the basin, and rawinsondes were flown from another location to the northeast of the city three times per day. Mixed layers grew to depths of 2500-3500 m, with a rapid period of growth beginning shortly before noon and lasting for several hours. Significant differences between the mixed-layer temperatures in the basin and outside the basin were observed. Three thermally and topographically driven flow patterns were observed that are consistent with previously hypothesized topographical and thermal forcing mechanisms. Despite these features, the circulation patterns in the basin important for the transport and diffusion of air pollutants show less day-to-day regularity than had been anticipated on the basis of Mexico City's tropical location, high altitude and strong insolation, and topographical setting.

  16. Exploratory study of particle-bound polycyclic aromatic hydrocarbons in different environments of Mexico City

    NASA Astrophysics Data System (ADS)

    Velasco, Erik; Siegmann, Philip; Siegmann, Hans C.

    2004-09-01

    Several studies regarding particulate matter in air pollution have been performed in Mexico City, but none have focused on environment exposure to particle-bound polycyclic aromatic hydrocarbons (PPAH), which are related to the occurrence of cardiopulmonary diseases and mortality. On this account, this study presents measurements of personal exposure to PPAH in different outdoor and indoor environments, as well as along roadways in Mexico City. The measurements were done with portable sensors based on photoelectric charging and diffusion charging to determine the PPAH concentrations and the joint active surface of all particles, respectively. The use of these two sensors in parallel is a useful tool to qualitatively identify the major sources and to describe the physical and chemical characteristics of the particles. The highest exposures were found in ambient air near traffic sources, mainly at sites with great influence of diesel vehicles, such as urban transfer bus stations. Roadway measurements showed that Mexican PPAH pollution levels are between those in large cities in Europe and USA. For indoor environments such as residences, shopping centers, restaurants and hospitality venues, it was found that secondhand smoke is the major contributor, however badly calibrated pilot stoves, inefficient ventilation and faulty air-conditioning systems can be additional sources of PPAH.

  17. [Itinerant physicians, the art of healing and doctors in national history (Mexico City, 1877-1911)].

    PubMed

    Agostoni, Claudia

    2008-01-01

    The uncertainty and mistrust towards the presence and activities of academic medical practitioners in Mexico City during the Porfirio Díaz government (1877-1911) convinced these professionals that is was essential to create, strengthen and transmit a respectable, competent and homogeneous image of the profession. To this purpose they recovered, recreated and adapted the ethical maxims of the occidental medical culture to their professional work, and rescued eminent medical figures of Mexico's convulse nineteenth century from being lost in the oblivion of history. Their goal - as it will be expounded in the following pages - was to respond, oppose and neutralize the criticism and disbelief expressed by the public against their professional performance.

  18. HIV prevalence, sociodemographic characteristics, and sexual behaviors among transwomen in Mexico City.

    PubMed

    Colchero, M Arantxa; Cortés-Ortiz, María Alejandra; Romero-Martínez, Martín; Vega, Hamid; González, Andrea; Román, Ricardo; Franco-Núñez, Aurora; Bautista-Arredondo, Sergio

    2015-01-01

    To present results from HIV testing, knowledge of HIV status and socioeconomic factors associated with the probability of having a HIV positive result among transwomen (TW) in Mexico. In 2012, we conducted an HIV seroprevalence survey to 585 TW in Mexico City in three strata: gathering places, the Condesa HIV Clinic and in four detention centers. We estimated the prevalence of HIV in each strata and applied a probit model to the overall sample to analyze factors associated with the probability of a HIV positive result. The prevalence of HIV was 19.8% in meeting places; 31.9% in detention centers and 64% among the participants of the clinic. Age, low education and number of sexual partners was positively associated with HIV. Results from the study provide relevant information to design HIV prevention interventions tailored to the needs of the TW population.

  19. Seroprevalence of Toxoplasma gondii antibodies in cats from Durango City, Mexico.

    PubMed

    Alvarado-Esquivel, C; Liesenfeld, O; Herrera-Flores, R G; Ramírez-Sánchez, B E; González-Herrera, A; Martínez-García, S A; Dubey, J P

    2007-10-01

    The prevalence of antibodies to Toxoplasma gondii was determined in sera from 105 domestic cats from Durango City, Mexico. Using a modified agglutination test, antibodies to this parasite were found in 21% of the 105 cats, with titers of 1:25 in 3 cats, 1:50 in 4 cats, 1:200 in 5 cats, 1:400 in 2 cats, 1:800 in 2 cats, 1:1,600 in 4 cats, and 1:3,200 or higher in 2 cats. Cats older than 1 yr had a significantly higher frequency of infection than that found in cats younger than 0.5 yr (41 vs. 13.2%, respectively; odds ratio = 4.55; 95% CI = 1.24-17.18; P = 0.01). Overall, the seroprevalence of T. gondii antibodies in cats in Durango, Mexico, is much lower compared with those reported in other countries.

  20. Serenity: Violence, Inequality, and Recovery on the Edge of Mexico City.

    PubMed

    Garcia, Angela

    2015-12-01

    Over the last decade, there has been a sharp increase in drug addiction in Mexico, especially among the urban poor. During the same period, unregulated residential treatment centers for addiction, known as anexos, have proliferated throughout the country. These centers are utilized and run by marginalized populations and are widely known to engage in physical violence. Based on long-term ethnographic research in Mexico City, this article describes why anexos emerged, how they work, and what their prevalence and practices reveal about the nature of recovery in a context where poverty, drugs, and violence are existential realities. Drawing attention to the dynamic relationship between violence and recovery, pain, and healing, it complicates categories of violence and care that are presumed to have exclusive meaning, illuminating the divergent meanings of, and opportunities for, recovery, and how these are socially configured and sustained. © 2015 by the American Anthropological Association.

  1. M protein gene type distribution among group A streptococcal clinical isolates recovered in Mexico City, Mexico, from 1991 to 2000, and Durango, Mexico, from 1998 to 1999: overlap with type distribution within the United States.

    PubMed

    Espinosa, Luz Elena; Li, Zhongya; Gomez Barreto, Demostenes; Calderon Jaimes, Ernesto; Rodriguez, Romeo S; Sakota, Varja; Facklam, Richard R; Beall, Bernard

    2003-01-01

    To examine the type distribution of pathogenic group A streptococcal (GAS) strains in Mexico, we determined the emm types of 423 GAS isolates collected from ill patients residing in Mexico (Durango or Mexico City). These included 282 throat isolates and 107 isolates from normally sterile sites. Of the other isolates, 38 were recovered from other miscellaneous infections. A total of 31 different emm types were found, revealing a broad overlap between commonly occurring emm types in Mexico and the United States. The information obtained in this study is consistent with the possibility that multivalent, M type-specific vaccines prepared for GAS strain distribution within the United States could theoretically protect against the majority of GAS strains causing disease in the two cities surveyed in Mexico.

  2. M Protein Gene Type Distribution among Group A Streptococcal Clinical Isolates Recovered in Mexico City, Mexico, from 1991 to 2000, and Durango, Mexico, from 1998 to 1999: Overlap with Type Distribution within the United States

    PubMed Central

    Espinosa, Luz Elena; Li, Zhongya; Barreto, Demostenes Gomez; Jaimes, Ernesto Calderon; Rodriguez, Romeo S.; Sakota, Varja; Facklam, Richard R.; Beall, Bernard

    2003-01-01

    To examine the type distribution of pathogenic group A streptococcal (GAS) strains in Mexico, we determined the emm types of 423 GAS isolates collected from ill patients residing in Mexico (Durango or Mexico City). These included 282 throat isolates and 107 isolates from normally sterile sites. Of the other isolates, 38 were recovered from other miscellaneous infections. A total of 31 different emm types were found, revealing a broad overlap between commonly occurring emm types in Mexico and the United States. The information obtained in this study is consistent with the possibility that multivalent, M type-specific vaccines prepared for GAS strain distribution within the United States could theoretically protect against the majority of GAS strains causing disease in the two cities surveyed in Mexico. PMID:12517875

  3. A driving cycle for vehicle emissions estimation in the metropolitan area of Mexico City.

    PubMed

    Schifter, I; Díaz, L; Rodríguez, R; López-Salinas, E

    2005-02-01

    A driving cycle derived from driving behavior and real traffic conditions in Mexico City (MC) is proposed. Data acquisition was carried out over diverse MC routes, representing travel under congested and uncongested conditions, using the chase-car approach. Thirteen different on-road patterns, including the four main access roads to MC, trips in both directions and different timetables, a total of 108 trips spanning 1044 km were evaluated in this study. The MC cycle lasts 1360 seconds with a distance of 8.8 km and average speed of 23.4 km h(-1). Both maximum speed (73.6 km h(-1)) and maximum acceleration (2.22 km h(-1)s(-1)) are lower than those of the new vehicles certification employed in Mexico ,FTP-75 cycle., that is, the MC cycle exhibits less cruising time and more transient events than the FTP cycle. A total of 30 light duty gasoline vehicles were classified into different technological groups and tested in an FTP-75 and MC driving cycles in order to compare their emission factors A potential concern is that in Mexico manufacturers design vehicles to meet the emission standards in the FTP, but emission levels increase significantly in a more representative cycle of present driving patterns in the Metropolitan Area of Mexico City (MAMC). The use of a more representative cycle during certification testing, would provide an incentive for vehicle manufacturers to design emissions control systems to remain effective during operation modes that are not currently represented in the official test procedures used in the certification process. Based on the results of the study, the use of MC cycle, which better represents current day driving patterns during testing of vehicle fleets in emissions laboratories, would improve the accuracy of emissions factors used in the MAMC emissions inventories.

  4. Spatial and temporal variability of particulate polycyclic aromatic hydrocarbons in Mexico City

    NASA Astrophysics Data System (ADS)

    Thornhill, D. A.; de Foy, B.; Herndon, S. C.; Onasch, T. B.; Wood, E. C.; Zavala, M.; Molina, L. T.; Gaffney, J. S.; Marley, N. A.; Marr, L. C.

    2008-06-01

    As part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) study in the Mexico City Metropolitan Area in March 2006, we measured particulate polycyclic aromatic hydrocarbons (PAHs) and other gaseous species and particulate properties, including light absorbing carbon or effective black carbon (BC), at six locations throughout the city. The measurements were intended to support the following objectives: to describe spatial and temporal patterns in PAH concentrations, to gain insight into sources and transformations of PAHs and BC, and to quantify the relationships between PAHs and other pollutants. Total particulate PAHs at the Instituto Mexicano del Petróleo (T0 supersite) located near downtown averaged 50 ng m-3, and aerosol active surface area averaged 80 mm2 m-3. PAHs were also measured on board the Aerodyne Mobile Laboratory, which visited six sites encompassing a mixture of different land uses and a range of ages of air parcels transported from the city core. A combination of analyses of time series, back trajectories, concentration fields, pollutant ratios, and correlation coefficients supports the concept of T0 as an urban source site, T1 as a receptor site with strong local sources, Pedregal and PEMEX as intermediate sites, Pico Tres Padres as a vertical receptor site, and Santa Ana as a downwind receptor site. Weak intersite correlations suggest that local sources are important and variable and that exposure to PAHs and BC cannot be represented by a single regional-scale value. The relationships between PAHs and other pollutants suggest that a variety of sources and ages of particles are present. Among carbon monoxide, nitrogen oxides (NOx), and carbon dioxide, particulate PAHs are most strongly correlated with NOx. Mexico City's PAH/BC mass ratio of 0.01 is similar to that found on a freeway loop in the Los Angeles area and approximately 8 30 times higher than that found in other cities. Evidence also suggests that primary

  5. Research the Mechanism of Land Subsidence in Typical Area, Beijing

    NASA Astrophysics Data System (ADS)

    Liu, H.; Zhang, Y.; Wang, R.; Gu, Z.

    2014-12-01

    In recently years, the subsidence develop rapidly in Beijing. It can not be ignored the influence of the security of major project. Beijing Singapore city is located at the junction of Daxing and Hebei. The per captia water resources is 190m3.,far below the internationally safety limit 1000m3. The region is the dryland water resource and continued extraction groundwater caused land subsidence issue become increasingly prominent. With the Beijing Singapore city put into use, the amount of water shortages must further seriously and land subsidence subsidence area must be further increased. Therefore, monitor the land subsidence of Beijing Singapore city area and research its settlement mechanism, it is so important to ensure the safe operation of Beijing Singapore city . Explore the soil and water coupling mechanism of Beijing Singapore citya during land subsidence process, and optimize groundwater extraction program to ensure the safe operation of Beijing's second largest airport.

  6. The impact of biogenic carbon emissions on aerosol absorption inMexico City

    SciTech Connect

    Marley, N; Gaffney, J; Tackett, M J

    2009-02-24

    In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption angstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbingmore » secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from {sup 14}C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The {sup 13}C/{sup 12}C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.« less

  7. Hepatitis C antibody prevalence among Mexico City prisoners injecting legal and illegal substances.

    PubMed

    Silverman-Retana, Omar; Serván-Mori, Edson; McCoy, Sandra I; Larney, Sarah; Bautista-Arredondo, Sergio

    2017-12-01

    Hepatitis C virus (HCV) infection is highly prevalent among prisoners and this prevalence estimates reach 64% among prisoners who inject illicit drugs. Prisons are important sites for HCV transmission in the absence of access to sterile injecting equipment; hence, it can be transmitted between prisoners who share contaminated needles and syringes. We aimed to estimate the prevalence of risk factors for anti-HCV prevalence, with particular interest on injecting behavior, and to assess correlates of anti-HCV positivity among Mexico City prisoners. Cross-sectional study based on information -collected in three male and two female prisons in Mexico City during 2010-2011- about sexually transmitted infections, socio-demographics, criminal history, substance use, vitamin injection, tattooing, among others (n=3,910). Weighted multivariable adjusted logistic regression models were estimated to assess the overall and differential odds for anti-HCV due to injecting behavior. Overall prevalence of anti-HCV was 3.3%. This figure rose to 43.1% among prisoners with a history of illicit drug injection. Prisoners with history of vitamin injection showed a similar prevalence of anti-HCV (43.8%). After stratifying by substance injected, the adjusted odds ratio was 9.8 (95% CI: 4.0, 23.8) for illicit drug injection and 11.9 (95% CI: 5.8, 23.8) for illicit drug and vitamin injection. Based on data from the most populous prisons in Mexico City, this study showed that anti-HCV is highly prevalent among prisoners with history of injecting behavior. In this sense, injecting behavior per-se, independent of the substance used, is associated with increased odds of anti-HCV positivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Climate change and its impact on water infrastructure: the case of Alcala de Henares (Spain) and Mexico City (Mexico)

    NASA Astrophysics Data System (ADS)

    Naranjo, M.; Tortajada, C.

    2012-04-01

    Climate change and its possible impacts on precipitation are still a matter of controversy due to lack of data as well as models which are considered reliable. Even though the science of climate change has advanced significantly in recent years, many uncertainties still prevail, ranging from reliable prediction of extreme river flow events to downscaling of rainfall to smaller planning areas. That is, present knowledge is still insufficient to understand and accurately predict how global changes, climate change one of them, may affect precipitation and streamflows over specific geographical units. In terms of planning and investment in urban areas, where more than 50 percent of the population live at present, freshwater supply and flood risk management have to be considered on long-term basis. This includes development of water infrastructure for drinking water supply and drainage as well as flood control which responds to the needs of the growing populations and their economies. Impacts of climate change are slow over time and take place over thousands of years. However, their study is relatively recent, mostly in terms of impacts on the hydrological cycle and therefore in terms of run-off. In the case of urban centres, the rationale is that governments will have to adapt the water infrastructure according to the expected changes and thus have to plan for them. For example, in the case of Mexico City, the way the drainage system was designed 100 years ago is very different from the way it would be done at present and the way it would be planned in about 50 years time. In the case of the city of Alcalá de Henares in the region of Madrid, the analysis of precipitations has shown a slight tendency towards a wet period from the decade of the 60´s. Due to this tendency, the calculations for the design of water infrastructures have remained virtually unchanged. In the case of this specific city, there is no indication that there will be dramatic or rapid changes in

  9. Archaeomagnetic Investigation at Chapultepec, Mexico City: Case Study of Classical Settlers

    NASA Astrophysics Data System (ADS)

    Lopez, V.; Romero, E.; Soler-Arechalde, A. M.; Espinosa, G.

    2007-05-01

    During the restoration campaign at the Chapultepec Park in Mexico City downtown, a teotihuacan settlement was found at the south flank of Chapultepec Hill. Samples represent a kind of irregular home kilns with a hole in their central part bounded by andesite rocks. Alternating field demagnetization had been employed. Rock magnetic measurements which included: Hysteresis, continuous susceptibility and isothermal remanence experiments revealed that some spinels, most probably magnetite or Ti-poor Titanomagnetites are responsible for the remanence. An archeomagnetic date obtained here is of 525 AD which is in good agreement with other evidences of the Teotihuacan Classic Metepec period (450-600 AD).

  10. Mexico.

    PubMed

    1993-01-01

    The background notes on Mexico provide text and recent statistical information on the geography, population, government, economy, and foreign relations, specifically the North American Free Trade Agreement with US. The 1992 population is estimated at 89 million of which 60% are mestizo (Indian-Spanish), 30% are American Indian, 9% are Caucasian, and 1% are other. 90% are Roman Catholic. There are 8 years of compulsory education. Infant mortality is 30/1000 live births. Life expectancy for males is 68 years and 76 years for females. The labor force is comprised of 30% in services, 24% in agriculture and fishing, 19% in manufacturing, 13% in commerce, 7% in construction, 4% in transportation and communication, and .4% in mining. There are 31 states and a federal district. Gross domestic product (GDP) per capita was $3200 in 1991. Military expenditures were .5% of GDP in 1991. The average inflation rate is 19%. Mexico City with 20 million is the largest urban center in the world. In recent years, the economy has been restructured with market oriented reforms; the result has been a growth of GDP of 3.6% in 1991 from 2% in 1987. Dependence on oil exports has decreased. There has been privatization and deregulation of state-owned companies. Subsidies to inefficient companies have been stopped. Tariff rates were reduced. The financial debt has been reduced and turned into a surplus of .8% in 1992. Mexico's foreign debt has been reduced from its high in 1987 of $107 billion. Agricultural reforms have been ongoing for 50 years. Land was redistributed, but standards of living and productivity have improved only slightly. Rural land tenure regulations have been changed, and other economic reforms are expected. Mexico engages in ad hoc international groups and is selective about membership in international organizations.

  11. [Effects of air pollution on human health and their importance in Mexico City].

    PubMed

    Vallejo, Maite; Jáuregui-Renaud, Kathrine; Hermosillo, Antonio G; Márquez, Manlio F; Cárdenas, Manuel

    2003-01-01

    The impact of air pollution on human health is a complicated problem. In this review, we describe the main health effects of exposure to ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead and particulate matter. Geographical characteristics of the metropolitan area of Mexico City that favor pollutant persistence with adverse effects on the population are described; the use of the Indice Metropolitano de la Calidad del Aire (IMECA), current norms, and present programs to diminish this problem are discussed. Evidence shows that through these actions, air quality has improved. However, some pollutants such as ozone and particulate matter, still exceed the standard. To further improve air quality in the city, existing programs should continue and multidisciplinary research, both basic and applied, is required.

  12. [Origins of institutional Pediatrics: Maternity and Childhood Hospital of Mexico City in the nineteenth century].

    PubMed

    Baeza Bacab, Manuel Antonio

    In June of 1866, the empress Carlota founded the Maternity House in the Department of Secret Births at the Hospice of the Poor. Upon the reinstatement of a republican government, Dr. Ramon Pacheco was appointed director of the Maternity House. Shortly after, in February of 1868, Dr. Luis Fernandez Gallardo established a pavilion for sick children in the Hospital of San Andres. After realizing this pavilion didn't have the adequate conditions to operate properly, and in the need of a children's hospital in Mexico City, Dr. Pacheco merged both institutions in April 2, 1869 -with the help of Ms. Luciana Arrazola- and founded the Maternity and Childhood Hospital, the first institution for the care of ill children in the independent Mexico. Ever since it was founded, Dr. Eduardo Liceaga was in charge of the children's health. Later, with the help of the presidents Juarez, Lerdo de Tejada and Díaz, he was able to consolidate the hospital in academic and health services aspects. This noble institution closed its doors on February 5, 1905, upon its incorporation to the General Hospital of Mexico, after 36 years of working for the welfare of Mexican children. Copyright © 2017 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

  13. [Prehospital emergency care in Mexico City: the opportunities of the healthcare system].

    PubMed

    Pinet, Luis M

    2005-01-01

    Unintentional vehicle traffic injuries cause 1.2 million preventable deaths per year worldwide, mostly affecting the population in their productive years of life. In Mexico, unintentional vehicle traffic injuries are one of the main causes of death; in Mexico City they account for 8% of deaths. Prehospital systems are set up to provide hospital medical care to the population, by means of a complex network that includes transportation, communications, resources (material, financial and human), and public participation. These systems may be designed in a variety of ways, depending on availability, capacity and quality of resources, according to specific community needs, always abiding by laws and regulations. In Mexico, several institutions and organizations offer prehospital services without being overseen in terms of coordination, regulation and performance evaluation, despite the high rates of morbidity and mortality due to injuries and preventable conditions amenable to effective therapy during the prehospital period. Prehospital care may contribute to decrease the morbidity and mortality rates of injuries requiring prompt medical care. Emphasis is made on the importance of assessing the performance of prehospital care, as well as on identification of needs for future development.

  14. Guardians of Health: The Dimensions of Elder Caregiving among Women in a Mexico City Neighborhood

    PubMed Central

    Mendez-Luck, Carolyn; Kennedy, David P; Wallace, Steven P

    2009-01-01

    Little is known about the family care of older adults in Mexico and the role of women in this process. To begin to fill this knowledge gap, this paper describes how a small sample of low-income women in one Mexico City neighborhood conceptualized the caregiver role and identified the forms of assistance they gave to their older relatives on a daily basis. A grounded theory approach was used to collect and analyze the data. Forty-one semi-structured qualitative interviews were conducted with female caregivers. The age of participants was between 19 and 83 years, and care recipients between 56-92 years. The relationship of caregiver to care recipient was wife, daughter, daughter-in-law, granddaughter, sibling, and other relative. The mean length of time providing care was five years. Most participants were not employed outside the home, and the median monthly household income was 2,000 pesos. We found that caregiving was a life changing event, with 27 of 41 participants viewing themselves as guardians. Caregivers' emphasis was on care recipients' emotional needs in order to provide “the most precious gift” of “time and attention.” Two forms of assistance were ‘keeping company’ and ‘watching out’ as safeguards against poor health or further decline in health. These findings increase the cultural understanding of caregiving in Mexico. Further research is needed to test the caregiving concepts identified in this study. PMID:19028415

  15. [Factors associated with the seeking of legal induced abortion services in Mexico City in 2010].

    PubMed

    Figueroa-Lara, Alejandro; Aracena-Genao, Belkis; Reyes-Morales, Hortensia; Lamadrid-Figueroa, Héctor

    2012-01-01

    To identify factors associated with the seeking of the legal-interruption-pregnancy (LIP) services in Mexico City. We used a case-control design. Users who utilized the LIP were defined as cases, while users of the antenatal care service with gestational age 13 or more weeks and who reported having an unwanted pregnancy were defined as controls. Logistic regressions were fitted to estimate odds ratios. Higher level of education (OR=1.47, 95% CI:1.04-2.07), women's occupation (being student OR=7.31, 95% CI:1.58-33.95; worker OR=13.43, 95% CI:2.04-88.54), and number of previous abortions (OR=11.41, 95% CI:1.65-79.07) were identified as factors associated with the lookup of LIP. In Mexico City context, empowered women with a higher level of education, or having a work activity are the users of LIP services. Strategies for improving access of women with low empowerment conditions are needed.

  16. Presence and prevalence of Batrachochytrium dendrobatidis in commercial amphibians in Mexico City.

    PubMed

    Galindo-Bustos, Miguel Angel; Hernandez-Jauregui, Dulce María Brousset; Cheng, Tina; Vredenburg, Vance; Parra-Olea, Gabriela

    2014-12-01

    In Mexico City, native and exotic amphibians are commonly sold through the pet trade. This study investigates the presence of Batrachochytrium dendrobatidis (Bd) in native amphibians being sold at two commercial markets and at a herpetarium in Mexico City. A total of 238 individuals (6 genera and 12 species) were tested for Bd using real-time polymerase chain reaction (PCR) analysis. There were 197 Bd-positive individuals (prevalence 82%) from five species of amphibians. Hyla eximia from the markets had very high Bd prevalence (100%; 76/76 and 99%; 88/89) but those from the herpetarium were Bd negative (0/12). Ambystoma mexicanum from the herpetarium also had a high Bd-positive prevalence (80%; 28/35). Though A. mexicanum is nearly extinct in the wild, a commercial market continues to flourish through the pet trade. Now that captive colonies of A. mexicanum are currently used for reintroduction programs, the authors recommend quarantine to reduce spread of Bd via movement of infected animals in the trade and between colonies and via disposal of wastewater from captive collections.

  17. Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City

    NASA Astrophysics Data System (ADS)

    Davis, Lucas W.

    2017-02-01

    Policymakers around the world are turning to license-plate based driving restrictions in an effort to address urban air pollution. The format differs across cities, but most programs restrict driving once or twice a week during weekdays. This paper focuses on Mexico City, home to one of the oldest and best-known driving restriction policies. For almost two decades Mexico City’s driving restrictions applied during weekdays only. This changed recently, however, when the program was expanded to include Saturdays. This paper uses hourly data from pollution monitoring stations to measure the effect of the Saturday expansion on air quality. Overall, there is little evidence that the program expansion improved air quality. Across eight major pollutants, the program expansion had virtually no discernible effect on pollution levels. These disappointing results stand in sharp contrast to estimates made before the expansion which predicted a 15%+ decrease in vehicle emissions on Saturdays. To understand why the program has been less effective than expected, the paper then turns to evidence from subway, bus, and light rail ridership, finding no evidence that the expansion was successful in getting drivers to switch to lower-emitting forms of transportation.

  18. Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City

    PubMed Central

    Davis, Lucas W.

    2017-01-01

    Policymakers around the world are turning to license-plate based driving restrictions in an effort to address urban air pollution. The format differs across cities, but most programs restrict driving once or twice a week during weekdays. This paper focuses on Mexico City, home to one of the oldest and best-known driving restriction policies. For almost two decades Mexico City’s driving restrictions applied during weekdays only. This changed recently, however, when the program was expanded to include Saturdays. This paper uses hourly data from pollution monitoring stations to measure the effect of the Saturday expansion on air quality. Overall, there is little evidence that the program expansion improved air quality. Across eight major pollutants, the program expansion had virtually no discernible effect on pollution levels. These disappointing results stand in sharp contrast to estimates made before the expansion which predicted a 15%+ decrease in vehicle emissions on Saturdays. To understand why the program has been less effective than expected, the paper then turns to evidence from subway, bus, and light rail ridership, finding no evidence that the expansion was successful in getting drivers to switch to lower-emitting forms of transportation. PMID:28151487

  19. Evaluation of a Social Marketing Campaign to Support Mexico City's Comprehensive Smoke-Free Law

    PubMed Central

    Huang, Liling; Pérez-Hernández, Rosaura; Niederdeppe, Jeff; Arillo-Santillán, Edna; Alday, Jorge

    2011-01-01

    Objectives. We aimed to assess the level of awareness and impact of a social marketing campaign to promote Mexico City's 2008 comprehensive smoke-free law. Methods. Four months after the smoke-free law was implemented but before the campaign launch, we collected data from a population-based, random sample of 961 inhabitants of Mexico City. We analyzed data from 786 respondents who completed follow-up at the end of the campaign to determine campaign exposure and the association between campaign exposure and changes in campaign-targeted knowledge and attitudes. Results. Recall of any of the 5 campaign materials was 69%, with a uniform distribution of exposure to 1, 2, and 3 or more campaign materials (25%, 25%, and 19%, respectively). Exposure to a greater number of campaign materials was associated in a monotonic relation with campaign-targeted knowledge of ammonia and arsenic in cigarette smoke. In models assessing support for, perceived benefits of, and perceived right to smoke-free places, campaign exposure accounted for a positive change in half of the indicators within each of these domains. Conclusions. Social marketing campaigns can reinforce knowledge and attitudes that favor smoke-free laws, thereby helping to establish smoke-free norms. PMID:21164097

  20. Development of pollution reduction strategies for Mexico City: Estimating cost and ozone reduction effectiveness

    SciTech Connect

    Thayer, G.R.; Hardie, R.W.; Barrera-Roldan, A.

    1993-12-31

    This reports on the collection and preparation of data (costs and air quality improvement) for the strategic evaluation portion of the Mexico City Air Quality Research Initiative (MARI). Reports written for the Mexico City government by various international organizations were used to identify proposed options along with estimates of cost and emission reductions. Information from appropriate options identified by SCAQMD for Southem California were also used in the analysis. A linear optimization method was used to select a group of options or a strategy to be evaluated by decision analysis. However, the reduction of ozone levels is not a linearmore » function of the reduction of hydrocarbon and NO{sub x} emissions. Therefore, a more detailed analysis was required for ozone. An equation for a plane on an isopleth calculated with a trajectory model was obtained using two endpoints that bracket the expected total ozone precursor reductions plus the starting concentrations for hydrocarbons and NO{sub x}. The relationship between ozone levels and the hydrocarbon and NO{sub x} concentrations was assumed to lie on this plane. This relationship was used in the linear optimization program to select the options comprising a strategy.« less

  1. [Prevalence of Chlamydia trachomatis infection in registered prostitutes in the city of Durango, Mexico].

    PubMed

    Alvarado-Esquivel, C; García-Villanueva, A; Castruita-Limones, D E; Cardosa-Nevárez, F J; Ruiz-Astorga, R

    2000-01-01

    To determine the prevalence of Chlamydia trachomatis infection among registered prostitutes of Durango City and to establish whether there is a correlation between epidemiological factors and infection. Two-hundred-and-forty-seven registered prostitutes of Durango city were studied. Endocervical samples and epidemiological data were obtained. C.trachomatis antigen was detected with the Chlamydiazyme test (Abbott Laboratories, USA.) Forty-one (16.6%) out of 247 prostitutes were positive to C. trachomatis. Thirty-seven out of the 41 positive women had had sexual activity on several States of Mexico (95.1%), as compared to only 109 out of 206 negative women (53.0%) (p < .0001). Prostitutes positive to C. trachomatis (39/41, 95.1%) were more likely to belong to low socioeconomic level than negatives (171/206, 83%) (p = 0.05). The prevalence of C. trachomatis infection was 16.6%. C. trachomatis infection was associated with sexual activity in multiple States of Mexico, and had a tendency to be associated with low socioeconomic level.

  2. Evaluation of a social marketing campaign to support Mexico City's comprehensive smoke-free law.

    PubMed

    Thrasher, James F; Huang, Liling; Pérez-Hernández, Rosaura; Niederdeppe, Jeff; Arillo-Santillán, Edna; Alday, Jorge

    2011-02-01

    We aimed to assess the level of awareness and impact of a social marketing campaign to promote Mexico City's 2008 comprehensive smoke-free law. Four months after the smoke-free law was implemented but before the campaign launch, we collected data from a population-based, random sample of 961 inhabitants of Mexico City. We analyzed data from 786 respondents who completed follow-up at the end of the campaign to determine campaign exposure and the association between campaign exposure and changes in campaign-targeted knowledge and attitudes. Recall of any of the 5 campaign materials was 69%, with a uniform distribution of exposure to 1, 2, and 3 or more campaign materials (25%, 25%, and 19%, respectively). Exposure to a greater number of campaign materials was associated in a monotonic relation with campaign-targeted knowledge of ammonia and arsenic in cigarette smoke. In models assessing support for, perceived benefits of, and perceived right to smoke-free places, campaign exposure accounted for a positive change in half of the indicators within each of these domains. Social marketing campaigns can reinforce knowledge and attitudes that favor smoke-free laws, thereby helping to establish smoke-free norms.

  3. Lead in human blood and milk from nursing women living near a smelter in Mexico City

    SciTech Connect

    Namihira, D.; Saldivar, L.; Pustilnik, N.

    The lead content in gasoline in Mexico City is the highest in the world (1g/L). The use of gasoline containing lead as an antiknock agent has been considered the major anthropogenic lead source in the area. Lead levels in breast milk and blood were determined in women living within a 200-m radius of 3 smelters in Mexico City. All samples were analyzed on a Perkin Elmer 460 atomic absorption spectrometer equipped with HGA 2200. The mean blood lead level was 45.88 [mu]g/dl (SD 19.88 [mu]g/dl), and the geometric mean of milk lead level was 2.47 [mu]g/100 ml. The correlation coefficientmore » of these two variables was 0.88. Using the mean value of lead found in breast milk, an infant of 5.5 kg would ingest 8.1 [mu]g/kg/d in his diet. The daily permissible intake (DPI) established by the World Health Organization (WHO) in 1972 for an adult is 5.0 [mu]g/kg/d. 32 refs., 3 figs., 1 tab.« less

  4. Optical Remote Sensing Measurements of Air Pollution in Mexico City During MCMA- 2006

    NASA Astrophysics Data System (ADS)

    Galle, B.; Mellqvist, J.; Johansson, M.; Rivera, C.; Samuelsson, J.; Zhang, Y.

    2007-05-01

    During March 2006 the Optical Remote sensing group at Chalmers University of Technology participated in the MCMA-2006 field campaign in Mexico City, performing measurements of air pollution using a set of different optical remote sensing instruments. This poster gives an overview of the techniques applied and results obtained. The techniques applied were: Solar Occultation FTIR and UV spectroscopy from fixed locations throughout the MCMA area, yielding total columns of CO, CH2O, SO2 and NO2. Long Path FTIR measurements from site T0 located in the north part of central Mexico City. With this instrument line-averaged concentration measurements of CO and CO2 was obtained in parallel with DOAS measurements performed by other partners. MAX-DOAS measurements from site T0, yielding total column and spatial distributions of SO2 and NO2. Mobile DOAS scattered Sunlight measurements of total columns of SO2 and NO2 in and around the MCMA area. Mobile and stationary DOAS measurements in the vicinity of Tula and Popocatépetl in order to quantify emissions from industry and volcano.

  5. Mexico.

    ERIC Educational Resources Information Center

    Semaan, Leslie

    The text explores Mexico's history, geography, art, religion, and lifestyles in the context of its complex economy. The text focuses on Mexico's economy and reasons for its current situation. Part I of this teaching unit includes: Teacher Overview, Why Study Mexico, Mexico Fact Sheet, Map of Mexico, the Land and Climate, History, Government,…

  6. Mercury levels in pregnant women, children, and seafood from Mexico City.

    PubMed

    Basu, Niladri; Tutino, Rebecca; Zhang, Zhenzhen; Cantonwine, David E; Goodrich, Jaclyn M; Somers, Emily C; Rodriguez, Lauren; Schnaas, Lourdes; Solano, Maritsa; Mercado, Adriana; Peterson, Karen; Sánchez, Brisa N; Hernández-Avila, Mauricio; Hu, Howard; Maria Téllez-Rojo, Martha

    2014-11-01

    Mercury is a global contaminant of concern though little is known about exposures in México. To characterize mercury levels in pregnant women, children, and commonly consumed seafood samples. Use resources of the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohorts to measure total mercury levels in archived samples from 348 pregnant women (blood from three trimesters and cord blood), 825 offspring (blood, hair, and urine) and their mothers (hair), and 91 seafood and canned tuna samples from Mexico City. Maternal blood mercury levels correlated across three trimesters and averaged 3.4 μg/L. Cord blood mercury averaged 4.7 μg/L and correlated with maternal blood from trimester 3 (but not trimesters 1 and 2). In children, blood, hair and urine mercury levels correlated and averaged 1.8 μg/L, 0.6 μg/g, and 0.9 μg/L, respectively. Hair mercury was 0.5 μg/g in mothers and correlated with child's hair. Mean consumption of canned tuna, fresh fish, canned sardine, and shellfish was 3.1, 2.2, 0.5, and 1.0 times per month respectively in pregnant women. Mean mercury content in 7 of 23 seafood species and 5 of 9 canned tuna brands purchased exceeded the U.S. EPA guidance value of 0.3 μg/g. Mercury exposures in pregnant women and children from Mexico City, via biomarker studies, are generally 3-5 times greater than values reported in population surveys from the U.S., Canada, and elsewhere. In particular, mercury levels in 29-39% of the maternal participants exceeded the biomonitoring guideline associated with the U.S. EPA reference dose for mercury. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Mercury Levels in Pregnant Women, Children, and Seafood from Mexico City

    PubMed Central

    Basu, Niladri; Tutino, Rebecca; Zhang, Zhenzhen; Cantonwine, David E.; Goodrich, Jaclyn M.; Somers, Emily C.; Rodriguez, Lauren; Schnaas, Lourdes; Solano, Maritsa; Mercado, Adriana; Peterson, Karen; Sánchez, Brisa N.; Hernández-Avila, Mauricio; Hu, Howard; Téllez-Rojo, Martha Maria

    2014-01-01

    Background Mercury is a global contaminant of concern though little is known about exposures in México. Objectives To characterize mercury levels in pregnant women, children, and commonly consumed seafood samples. Methods Use resources of the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohorts to measure total mercury levels in archived samples from 348 pregnant women (blood from three trimesters and cord blood), 825 offspring (blood, hair, urine) and their mothers (hair), and 91 seafood and canned tuna samples from Mexico City. Results Maternal blood mercury levels correlated across three trimesters and averaged 3.4μg/L. Cord blood mercury averaged 4.7μg/L and correlated with maternal blood from trimester 3 (but not trimesters 1 and 2). In children, blood, hair and urine mercury levels correlated and averaged 1.8μg/L, 0.6μg/g, and 0.9μg/L, respectively. Hair mercury was 0.5μg/g in mothers and correlated with child's hair. Mean consumption of canned tuna, fresh fish, canned sardine, and shellfish was 3.1, 2.2, 0.5, and 1.0 times per month respectively in pregnant women. Mean mercury content in 7 of 23 seafood species and 5 of 9 canned tuna brands purchased exceeded the U.S. EPA guidance value of 0.3 μg/g. Conclusions Mercury exposures in pregnant women and children from Mexico City, via biomarker studies, are generally 3-5 times greater than values reported in population surveys from the U.S., Canada, and elsewhere. In particular, mercury levels in 29-39% of the maternal participants exceeded the biomonitoring guideline associated with the U.S. EPA reference dose for mercury. PMID:25262076

  8. Risk to a Changing Climate in the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Vargas, N. D.

    2016-12-01

    The issue of climate change has dominated the atmospheric sciences agenda in recent decades. The concern about an increase in climate related disasters, mainly in large population centers, has led to ask whether they are mainly due to changes in climate or in vulnerability.The Mexico City Metropolitan Area (MCMA) is an example of megalopolis under high climate risk, where floods, landslides, health problems, high air pollution events, socioeconomic droughts are becoming important environmental and social problems. As urbanization spreads and population increases exposure to natural hazards increases, and so the magnitude of risk to a changing climate and the negative impacts. Since the late nineteenth century, in the MCMA an average maximum temperature could be around 22°C, whereas today it is about 24.5ºC. That is, the increase in the average temperature in Mexico City is around 3°C in a hundred years. But there are areas where an increase in the average temperature is similar in only thirty years. The heating rate of the city can vary depending on the change in land use. Areas that conserve forested regions in the process of urbanization tend to warm less than areas where the transformation into concrete and cement is almost complete. Thus, the climate of the MCMA shows important changes mainly in relation to land use changes. Global warming and natural climate variability were also analyzed as possible forcing factors of the observed warming by comparing low frequency variations in local temperature and indices for natural forcing. The hydrological cycle of the MCMA has also changed with urbanization. The "bubble of hot air" over the urban area has more capacity to hold moisture now than before the UHI. However, the increased risk to floods, heat or drought appears to be related not only to more frequent intense climatic hazards induced by the urbanization effect. This process also induces increased vulnerability to a changing climate. The establishment of

  9. An overview of the MILAGRO 2006 campaign: Mexico City emissions and their transport and transformation

    NASA Astrophysics Data System (ADS)

    Molina, L. T.; Madronich, S.; Gaffney, J. S.; Apel, E.; de Foy, B.; Fast, J.; Ferrare, R.; Herndon, S.; Jimenez, J. L.; Lamb, B.; Osornio-Vargas, A. R.; Russell, P.; Schauer, J. J.; Stevens, P. S.; Zavala, M.

    2010-03-01

    MILAGRO (Megacity Initiative: Local And Global Research Observations) is an international collaborative project to examine the behavior and the export of atmospheric emissions from a megacity. The Mexico City Metropolitan Area (MCMA) - one of the world's largest megacities and North America's most populous city - was selected as the case study to characterize the sources, concentrations, transport, and transformation processes of the pollutants emitted to the MCMA atmosphere and to evaluate the regional and global impacts of these emissions. The findings of this study are relevant to the evolution and impacts of pollution from many other megacities. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, and enlisting over 450 scientists from 150 institutions in 30 countries. Three ground supersites were set up to examine the evolution of the primary emitted gases and fine particles. Additional platforms in or near Mexico City included mobile vans containing scientific laboratories and mobile and stationary upward-looking lidars. Seven instrumented research aircraft provided information about the atmosphere over a large region and at various altitudes. Satellite-based instruments peered down into the atmosphere, providing even larger geographical coverage. The overall campaign was complemented by meteorological forecasting and numerical simulations, satellite observations and surface networks. Together, these research observations have provided the most comprehensive characterization of the MCMA's urban and regional atmospheric composition that will take years to analyze and evaluate fully. In this paper we review over 120 papers resulting from the MILAGRO/INTEX-B Campaign that have been published or submitted, as

  10. An overview of the MILAGRO 2006 Campaign: Mexico City emissions and their transport and transformation

    NASA Astrophysics Data System (ADS)

    Molina, L. T.; Madronich, S.; Gaffney, J. S.; Apel, E.; de Foy, B.; Fast, J.; Ferrare, R.; Herndon, S.; Jimenez, J. L.; Lamb, B.; Osornio-Vargas, A. R.; Russell, P.; Schauer, J. J.; Stevens, P. S.; Volkamer, R.; Zavala, M.

    2010-09-01

    MILAGRO (Megacity Initiative: Local And Global Research Observations) is an international collaborative project to examine the behavior and the export of atmospheric emissions from a megacity. The Mexico City Metropolitan Area (MCMA) - one of the world's largest megacities and North America's most populous city - was selected as the case study to characterize the sources, concentrations, transport, and transformation processes of the gases and fine particles emitted to the MCMA atmosphere and to evaluate the regional and global impacts of these emissions. The findings of this study are relevant to the evolution and impacts of pollution from many other megacities. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, and enlisting over 450 scientists from 150 institutions in 30 countries. Three ground supersites were set up to examine the evolution of the primary emitted gases and fine particles. Additional platforms in or near Mexico City included mobile vans containing scientific laboratories and mobile and stationary upward-looking lidars. Seven instrumented research aircraft provided information about the atmosphere over a large region and at various altitudes. Satellite-based instruments peered down into the atmosphere, providing even larger geographical coverage. The overall campaign was complemented by meteorological forecasting and numerical simulations, satellite observations and surface networks. Together, these research observations have provided the most comprehensive characterization of the MCMA's urban and regional atmospheric composition and chemistry that will take years to analyze and evaluate fully. In this paper we review over 120 papers resulting from the MILAGRO/INTEX-B Campaign that have been published or submitted, as well as relevant

  11. NO2 DOAS measurements from ground and space: comparison of ground based measurements and OMI data in Mexico City

    NASA Astrophysics Data System (ADS)

    Rivera, C.; Stremme, W.; Grutter, M.

    2012-04-01

    The combination of satellite data and ground based measurements can provide valuable information about atmospheric chemistry and air quality. In this work we present a comparison between measured ground based NO2 differential columns at the Universidad Nacional Autónoma de México (UNAM) in Mexico City, using the Differential Optical Absorption Spectroscopy (DOAS) technique and NO2 total columns measured by the Ozone Monitoring Instrument (OMI) onboard the Aura satellite using the same measurement technique. From these data, distribution maps of average NO2 above the Mexico basin were constructed and hot spots inside the city could be identified. In addition, a clear footprint was detected from the Tula industrial area, ~50 km northwest of Mexico City, where a refinery, a power plant and other industries are located. A less defined footprint was identified in the Cuernavaca basin, South of Mexico City, and the nearby cities of Toluca and Puebla do not present strong enhancements in the NO2 total columns. With this study we expect to cross-validate space and ground measurements and provide useful information for future studies.

  12. Lead in candy consumed and blood lead levels of children living in Mexico City.

    PubMed

    Tamayo y Ortiz, Marcela; Téllez-Rojo, Martha María; Hu, Howard; Hernández-Ávila, Mauricio; Wright, Robert; Amarasiriwardena, Chitra; Lupoli, Nicola; Mercado-García, Adriana; Pantic, Ivan; Lamadrid-Figueroa, Héctor

    2016-05-01

    Recent studies have shown that lead exposure continues to pose a health risk in Mexico. Children are a vulnerable population for lead effects and Mexican candy has been found to be a source of exposure in children. There are no previous studies that estimates lead concentrations in candy that children living in Mexico City consume and its association with their blood lead level. To evaluate whether there is an association between reported recent consumption of candies identified to have lead, and blood lead levels among children in Mexico City. A subsample of 171 children ages 2-6 years old, from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study was assessed between June 2006 and July 2007. The candy reported most frequently were analyzed for lead using ICP-MS. The total weekly intake of lead through the consumption of candy in the previous week was calculated. Capillary blood lead levels (BLL) were measured using LeadCare (anodic stripping voltammetry). Lead concentrations ≥0.1ppm, the FDA permitted level (range: 0.13-0.7ppm) were found in 6 samples out of 138 samples from 44 different brands of candy. Median BLL in children was 4.5µg/dl. After adjusting for child's sex, age, BMI, maternal education & occupation, milk consumption, sucking the candy wrapper, use of lead-glazed pottery, child exposure behavior, living near a lead exposure site and use of folk remedies, an increase of 1µg of lead ingested through candy per week was associated with 3% change (95% CI: 0.1%, 5.2%) in BLL. Although lead concentrations in candy were mostly below the FDA permitted level, high lead concentrations were detected in 4% of the candy samples and 12% of brands analyzed. Although candy intake was modestly associated with children's BLL, lead should not be found in consumer products, especially in candy that children can consume due to the well documented long-lasting effect of lead exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Air Quality in Megacities: Lessons Learned from Mexico City Field Measurements

    NASA Astrophysics Data System (ADS)

    Molina, L. T.

    2014-12-01

    More than half of the world's population now lives in urban areas because of the opportunities for better jobs, access to city services, cultural and educational activities, and a desire for more stimulating human interaction. At the same time, many of these urban centers are expanding rapidly, giving rise to the phenomenon of megacities. In recent decades air pollution has become not only one of the most important environmental problems of megacities, but also presents serious consequences to human health and ecosystems and economic costs to society. Although the progress to date in combating air pollution problems in developed and some developing world megacities has been impressive, many challenges remain including the need to improve air quality while simultaneously mitigating climate change. This talk will present the results and the lessons learned from field measurements conducted in Mexico City Metropolitan Area - one of the world's largest megacities - over the past decade. While each city has its own unique circumstances, the need for an integrated assessment approach in addressing complex environmental problems is the same. There is no single strategy in solving air pollution problems in megacities; a mix of policy measures based on sound scientific findings will be necessary to improve air quality, protect public health, and mitigate climate change.

  14. Flux Measurements of Trace Gases, Aerosols and Energy from the Urban Core of Mexico City

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Molina, L.; Lamb, B.; Pressley, S.; Grivicke, R.; Westberg, H.; Jobson, T.; Allwine, E.; Coons, T.; Jimenez, J.; Nemitz, E.; Alexander, L. M.; Worsnop, D.; Ramos, R.

    2007-05-01

    As part of the MILAGRO field campaign in March 2006 we deployed a flux system in a busy district of Mexico City surrounded by congested avenues. The flux system consisted of a tall tower instrumented with fast-response sensors coupled with eddy covariance (EC) techniques to measure fluxes of volatile organic compounds (VOCs), CO2, CO, aerosols and energy. The measured fluxes represent direct measurements of emissions that include all major and minor emission sources from a typical residential and commercial district. In a previous study we demonstrated that the EC techniques are valuable tools to evaluate emissions inventories in urban areas, and understand better the atmospheric chemistry and the role that megacities play in global change. We measured fluxes of olefins using a Fast Olefin Sensor (FOS) and the EC technique, fluxes of aromatic and oxygenated VOCs by Proton Transfer Reaction-Mass Spectroscopy (PTR-MS) and the disjunct eddy covariance (DEC) technique, fluxes of CO2 and H2O with an open path Infrared Gas Analyzer (IRGA) and the EC technique, fluxes of CO using a modified gradient method and a commercial CO instrument, and fluxes of aerosols (organics, nitrates and sulfates) using an Aerodyne Aerosol Mass Spectrometer (AMS) and the EC technique. In addition we used a disjunct eddy accumulation (DEA) system to extend the number of VOCs. This system collected whole air samples as function of the direction of the vertical wind component, and the samples were analyzed on site using gas chromatography / flame ionization detection (GC-FID). We also measured fluxes of sensible and latent heat by EC and the radiation components with a net radiometer. Overall, these flux measurements confirm the results of our previous flux measurements in Mexico City in terms of the magnitude, composition, and distribution. We found that the urban surface is a net source of CO2 and VOCs. The diurnal patterns show clear anthropogenic signatures, with important contributions from

  15. Variability of winter and summer surface ozone in Mexico City on the intraseasonal timescale

    NASA Astrophysics Data System (ADS)

    Barrett, Bradford S.; Raga, Graciela B.

    2016-12-01

    Surface ozone concentrations in Mexico City frequently exceed the Mexican standard and have proven difficult to forecast due to changes in meteorological conditions at its tropical location. The Madden-Julian Oscillation (MJO) is largely responsible for intraseasonal variability in the tropics. Circulation patterns in the lower and upper troposphere and precipitation are associated with the oscillation as it progresses eastward around the planet. It is typically described by phases (labeled 1 through 8), which correspond to the broad longitudinal location of the active component of the oscillation with enhanced precipitation. In this study we evaluate the intraseasonal variability of winter and summer surface ozone concentrations in Mexico City, which was investigated over the period 1986-2014 to determine if there is a modulation by the MJO that would aid in the forecast of high-pollution episodes. Over 1 000 000 hourly observations of surface ozone from five stations around the metropolitan area were standardized and then binned by active phase of the MJO, with phase determined using the real-time multivariate MJO index. Highest winter ozone concentrations were found in Mexico City on days when the MJO was active and in phase 2 (over the Indian Ocean), and highest summer ozone concentrations were found on days when the MJO was active and in phase 6 (over the western Pacific Ocean). Lowest winter ozone concentrations were found during active MJO phase 8 (over the eastern Pacific Ocean), and lowest summer ozone concentrations were found during active MJO phase 1 (over the Atlantic Ocean). Anomalies of reanalysis-based cloud cover and UV-B radiation supported the observed variability in surface ozone in both summer and winter: MJO phases with highest ozone concentration had largest positive UV-B radiation anomalies and lowest cloud-cover fraction, while phases with lowest ozone concentration had largest negative UV-B radiation anomalies and highest cloud

  16. Measurements of Criteria Pollutants in Suburban Locations in the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Fentanes, O.; Sanchez, A.; Garcia, A.; Martinez, A.

    2004-12-01

    In the town of Santa Ana in the southern part of the Mexico City Metropolitan Area (MCMA) at an approximate height of 370 meters above the Valley of Mexico, a series of criteria pollutants (nitrogen dioxide, ozone, sulfur dioxide, and carbon monoxide) and meteorological parameters (wind speed and direction, temperature and relative humidity) were measured during the MCMA-2003 field campaign during April 2003. Santa Ana is considered a border site, agriculture being the predominant activity. The generated data in Santa Ana was compared with those from two representative atmospheric monitoring stations from the southeast zone (CENICA Supersite) and southwest (Revolucion Station) of Mexico City. The carbon monoxide and ozone concentrations measured in Santa Ana are atypical for a rural area. The sulfur dioxide and nitrogen dioxide concentrations are characteristic of the local activity. The average obtained during the measurement time for carbon monoxide was 0.86 ppm, the presence of the contaminant was within a 0.3 to 1.5 ppm range, 5 to 95 percentile, and does not follow the observed behavior of the monitoring stations that are located inside the urban area, although during the night (10 pm to 6 am) the carbon monoxide in Santa Ana was preset in levels from 0.4 to 1.5 ppm, 5 to 95 percentiles, average 0.92 ppm, above the reported concentrations at Revolucion Station, levels from 0.1 to 1.7 ppm, 5 to 95 percentiles; average 0.72 ppm. The presence of this contaminant can be attributed to transportation and accumulation phenomena. The ozone daytime behavior is similar to the one observed in the CENICA and Revolucion stations, but with a lower magnitude, the daily maximum generally occuring 2 or 3 hours after the urban stations. The one-hour average maximum values were 133 ppb in Santa Ana area and 188 ppb in the city. During the night the average concentrations were 37 ppb in Santa Ana and 17 ppb in the urban area. Nevertheless, the ozone average value in Santa Ana

  17. Preliminary subsidence investigation of Sacramento Valley, California

    USGS Publications Warehouse

    Lofgren, B.E.; Ireland, R.L.

    1973-01-01

    Although a number of agencies have made leveling surveys in Sacramento Valley and a valleywide network of first- and second-order control exists, few areas have sufficient control for determining whether land subsidence has occurred and if so, how much, within the time span of vertical control. Available data suggest that 0.2 to 0.9 foot (0.06 to 0.3 m) of subsidence probably has occurred from 1935-42 to 1964 in an extensive agricultural area of heavy ground-water pumping between Zamora and Davis, and that as much as 2 feet (0.6 m) of subsidence has occurred in at least two areas of pumping overdraft--east of Zamora, and west of Arbuckle. A comparison of maps showing long-term water-level decline and average annual ground-water pumpage indicates several other areas of probable subsidence. In six general areas--northwest of Sacramento; northeast of Sacramento; southeast of Yuba City; 10 miles (16 km) north of Willows; 20 miles (32 km) north of Willows; and especially in the Arbuckle area,ground-water declines have quite probably produced significant subsidence. In two areas of most intensive pumping, no long-term water-level declines have occurred, and no subsidence is indicated. If problems of land subsidence are of concern in Sacramento Valley, and if estimates of historic subsidence or subsidence potential are needed, serious consideration should be given to a field program of basic-data collection. Second-order leveling along a few carefully selected lines of existing control, and the installation and operation of two or three compaction recorders in areas of continuing water-level decline, would provide helpful data for estimating .past and future subsidence.

  18. A Tale of two Cities: Photoacoustic and Aethalometer Measurements Comparisons of Light Absorption in Mexico City and Las Vegas, NV, USA

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Marley, N. A.; Gaffney, J. S.

    2007-05-01

    As part of the Megacity Impacts on Regional and Global Environments, MIRAGE-Mex deployment to Mexico City in the period of 30 days, March 2006, a suite of photoacoustic spectrometers (PAS; W. Arnott & G. Paredes), nephelometer scattering, and aetholemeter absorption instruments (N. Marley & J.Gaffney) were installed to measure at ground level the light absorption and scattering by aerosols at the urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). This IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed. The Las Vegas, NV site was located at East Charleston Street on January-February, 2003. In east Las Vegas typical westerly winds carry the city plume across the site. Comparisons of PAS aerosol light absorption and aetholemeter absorption measurements at 521 nm at both Las Vegas NV and Mexico City sites will be presented. We will also present a broad overview of the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the sites in relation to secondary aerosol formation.

  19. Using high-resolution satellite aerosol optical depth to estimate daily PM2.5 geographical distribution in Mexico City

    PubMed Central

    Just, Allan C.; Wright, Robert O.; Schwartz, Joel; Coull, Brent A.; Baccarelli, Andrea A.; Tellez-Rojo, Martha María; Moody, Emily; Wang, Yujie; Lyapustin, Alexei; Kloog, Itai

    2015-01-01

    Recent advances in estimating fine particle (PM2.5) ambient concentrations use daily satellite measurements of aerosol optical depth (AOD) for spatially and temporally resolved exposure estimates. Mexico City is a dense megacity that differs from other previously modeled regions in several ways: it has bright land surfaces, a distinctive climatological cycle, and an elevated semi-enclosed air basin with a unique planetary boundary layer dynamic. We extend our previous satellite methodology to the Mexico City area, a region with higher PM2.5 than most US and European urban areas. Using a novel 1 km resolution AOD product from the MODIS instrument, we constructed daily predictions across the greater Mexico City area for 2004–2014. We calibrated the association of AOD to PM2.5 daily using municipal ground monitors, land use, and meteorological features. Predictions used spatial and temporal smoothing to estimate AOD when satellite data were missing. Our model performed well, resulting in an out-of-sample cross validation R2 of 0.724. Cross-validated root mean squared prediction error (RMSPE) of the model was 5.55 μg/m3. This novel model reconstructs long- and short-term spatially resolved exposure to PM2.5 for epidemiological studies in Mexico City. PMID:26061488

  20. [Comparison of climacteric symptoms among women in Mexico City and women of a Mayan community of Yucatan].

    PubMed

    Carranza-Lira, Sebastián; Quiroz González, Byanca Nerea; Alfaro Godinez, Hugo César; May Can, Ana María

    2012-10-01

    to compare the climacteric symptoms between women from Mexico City and those from a Mayan community of the state of Yucatan. In two groups of women, Group I) Spanish-speaking women from Mexico City and Group II) Maya speaking women from the state of Yucatan, 22 climacteric symptoms were evaluated using an analog visual scale (AVS) and the SUMEVA index. For statistical analysis t student test was used as well as Chi squared. 105 women, 50 of Mexico City and 55 of Maxcanu, Yucatan were studied. When comparing the groups no difference was found in age (52.5 +/- 6.5 vs 53.7 +/- 6.2, for group I and II respectively), the body mass index was significantly smaller in group I (29.7 +/- 5.0 vs 34.0 +/- 6.0, p < 0.001). In group 1, 15 of the 22 evaluated symptoms were significantly more intense in Group I, as well as the SUMEVA (Sum of Analog Visual Scale) index (71.4 +/- 44.5 vs 45.8 +/- 24.8, p < 0.001). The proportion of symptomatic women for each one of the symptoms was similar in both groups except for hair fall that was significantly greater in group I (74% vs 52%). climacteric symptoms were perceived with more intensity by Mexico City women, which allows suppose that western culture influence can be the responsible.

  1. Using High-Resolution Satellite Aerosol Optical Depth To Estimate Daily PM2.5 Geographical Distribution in Mexico City.

    PubMed

    Just, Allan C; Wright, Robert O; Schwartz, Joel; Coull, Brent A; Baccarelli, Andrea A; Tellez-Rojo, Martha María; Moody, Emily; Wang, Yujie; Lyapustin, Alexei; Kloog, Itai

    2015-07-21

    Recent advances in estimating fine particle (PM2.5) ambient concentrations use daily satellite measurements of aerosol optical depth (AOD) for spatially and temporally resolved exposure estimates. Mexico City is a dense megacity that differs from other previously modeled regions in several ways: it has bright land surfaces, a distinctive climatological cycle, and an elevated semi-enclosed air basin with a unique planetary boundary layer dynamic. We extend our previous satellite methodology to the Mexico City area, a region with higher PM2.5 than most U.S. and European urban areas. Using a novel 1 km resolution AOD product from the MODIS instrument, we constructed daily predictions across the greater Mexico City area for 2004-2014. We calibrated the association of AOD to PM2.5 daily using municipal ground monitors, land use, and meteorological features. Predictions used spatial and temporal smoothing to estimate AOD when satellite data were missing. Our model performed well, resulting in an out-of-sample cross-validation R(2) of 0.724. Cross-validated root-mean-squared prediction error (RMSPE) of the model was 5.55 μg/m(3). This novel model reconstructs long- and short-term spatially resolved exposure to PM2.5 for epidemiological studies in Mexico City.

  2. Diagnosis and treatment of presumed STIs at Mexican pharmacies: survey results from a random sample of Mexico City pharmacy attendants

    PubMed Central

    Turner, A; Ellertson, C; Thomas, S; Garcia, S

    2003-01-01

    Objectives: People in developing countries often seek medical advice for common ailments from pharmacies. As one example, pharmacists routinely diagnose and treat symptomatic sexually transmitted infections (STIs). We aimed to assess the quality of advice provided in Mexico City pharmacies by presenting hypothetical STI related syndromes and recording pharmacy attendants' suggested diagnoses and treatments. Methods: We interviewed the first available attendant in each of a 5% random sample of Mexico City's pharmacies. We inquired about the training, age, and experience of the attendant and about the typical number of clients coming for treatment of suspected STIs. After considering three hypothetical case studies, attendants recommended diagnoses, treatments, and, sometimes, physician follow up. Results: Most Mexico City "pharmacists" are actually clerks, with trained pharmacists rarely available on the premises. The average pharmacy attendant was 32 years old, with a median of 5 years' experience at that pharmacy, but very limited (if any) training. 62% reported seeing 10 or more clients with genital or vaginal infections per month. Depending on the case study, attendants provided appropriate diagnoses in 0–12% of cases, recommended appropriate treatments in 12–16% of cases, and suggested physician follow up for 26–67% of cases. Conclusions: In general, surveyed pharmacy personnel were unable to diagnose accurately or offer appropriate treatment advice when presented with classic, common STI symptoms. Given the volume of clients seeking advice from this source, training pharmacy attendants could significantly help to reduce the burden of disease associated with STIs in Mexico City. PMID:12794207

  3. CHARACTERIZATION OF A SPATIAL GRADIENT OF NITROGEN DIOXIDE ACROSS A UNITED STATES-MEXICO BORDER CITY DURING WINTER

    EPA Science Inventory

    A gradient of ambient nitrogen dioxide (NO2) concentration is demonstrated across metropolitan El Paso, Texas (USA), a city located on the international border between the United States and Mexico. Integrated measurements of NO2 were collected over seven days at 20 elementary sc...

  4. Diversity-Based Characteristics of Mexican Children's Drawings: A Qualitative Analysis of Drawings Collected in Mexico City

    ERIC Educational Resources Information Center

    Hass-Cohen, Noah; Chandler-Ziegler, Karina; Veeman, Thomas; Funk, Sterling

    2016-01-01

    The purpose of this study was to increase understanding of the diversity of characteristics in the drawings of children in Mexico City. The authors conducted a thematic analysis of 174 drawings from children ages 6 to 11 that revealed two main discrete themes: nature and stress. A personalized, supportive relationship with nature emerged as a…

  5. Qualitative Inquiry with Women in Poverty in Mexico City: Reflections on the Emotional Responses of a Research Team

    ERIC Educational Resources Information Center

    Martinez-Salgado, Carolina

    2009-01-01

    While conducting a qualitative inquiry involving in-depth interviews on the perceptions of health risks within a group of profoundly poor urban families in the southern part of Mexico City, Martinez-Salgado and her interdisciplinary team of women interviewers got involved in emotionally complex situations with the women participants in the study.…

  6. Complete Genome Sequence of Paenibacillus larvae MEX14, Isolated from Honey Bee Larvae from the Xochimilco Quarter in Mexico City

    PubMed Central

    Peréz de la Rosa, D.; Pérez de la Rosa, J. J.; Cossio-Bayugar, R.; Miranda-Miranda, E.; Lozano, L.; Bravo-Díaz, M. A.; Rocha-Martínez, M. K.

    2015-01-01

    Paenibacillus larvae strain MEX14 is a facultative anaerobic endospore-forming bacterium that infects Apis mellifera larvae. Strain MEX14 was isolated from domestic bee larvae collected in a backyard in Mexico City. The estimated genome size was determined to be 4.18 Mb, and it harbors 4,806 protein coding genes (CDSs). PMID:26316636

  7. Incidence of leukemias in children from El Salvador and Mexico City between 1996 and 2000: Population-based data

    PubMed Central

    Mejía-Aranguré, Juan Manuel; Bonilla, Miguel; Lorenzana, Rodolpho; Juárez-Ocaña, Servando; de Reyes, Gladys; Pérez-Saldivar, María Luisa; González-Miranda, Guadalupe; Bernáldez-Ríos, Roberto; Ortiz-Fernández, Antonio; Ortega-Alvarez, Manuel; Martínez-García, María del Carmen; Fajardo-Gutiérrez, Arturo

    2005-01-01

    Background There are very few studies that report the incidence of acute leukemias in children in Latin America. This work assesses the incidence of acute leukemias, between 1996 and 2000, in children from 0–14 years old who were attended at the Mexican Social Security Institute in Mexico City and in children from 0–11 years old in El Salvador. Methods Design: Population-based data. Hospitals: In San Salvador, El Salvador, Hospital Nacional de Niños "Benjamín Bloom", the only center in El Salvador which attends all children, younger than 12 years, with oncologic disease. The Pediatric Hospital and the General Hospital of the Mexican Social Security Institute in Mexico City, the only centers in Mexico City which attend all those children with acute leukemia who have a right to this service. Diagnosis: All patients were diagnosed by bone marrow smear and were divided into acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and unspecified leukemias (UL). The annual incidence rate (AIR) and average annual incidence rate (AAIR) were calculated per million children. Cases were stratified by age and assigned to one of four age strata: 1) <1 year; 2) 1–4 years; 3) 5–9 years, or 4) 10–14 or 10–11 years, for Mexico City and El Salvador, respectively. Results The number of cases was 375 and 238 in El Salvador and Mexico City, respectively. AAIRs in Mexico City were 44.9, 10.6, 2.5, 0.5, and 58.4 per million children for ALL, AML, CML, UL, and total leukemias, respectively. The AAIRs in El Salvador could not be calculated because the fourth age stratum in El Salvador included children only from 0–11 years old. The incidence rates for the Salvadoran group of 0–11 year olds were 34.2, 7.1, 0.6, 0.2, and 43.2 per million children for ALL, AML, CML, UL, and total leukemias, respectively. Conclusion Reported AIRs for each age group in El Salvador were similar to those from other American countries. The AAIR of ALL in

  8. Primates as pets in Mexico City: an assessment of the species involved, source of origin, and general aspects of treatment.

    PubMed

    Duarte-Quiroga, Alejandra; Estrada, Alejandro

    2003-10-01

    The large human populations in cities are an important source of demand for wildlife pets, including primates, and not much is known about the primate species involved in terms of their general origin, the length of time they are kept as pets, and some of the maintenance problems encountered with their use as pets. We report the results of a survey conducted in Mexico City among primate pet owners, which was aimed at providing some of the above information. We used an ethnographic approach, and pet owners were treated as informants to gain their trust so that we could enter their homes and learn about the life of their primate pets. We surveyed 179 owners of primate pets, which included 12 primate species. Of these, three were native species (Ateles geoffroyi, Alouatta pigra, and A. palliata). The rest were other neotropical primate species not native to Mexico, and some paleotropical species. Spider monkeys and two species of howler monkeys native to Mexico accounted for 67% and 15%, respectively, of the primate cases investigated. The most expensive primate pets were those imported from abroad, while the least expensive were the Mexican species. About 45% of the native primate pets were obtained by their owners in a large market in Mexico City, and the rest were obtained in southern Mexico. Although they can provide companionship for children and adults, primate pets are subject to a number of hazards, some of which put their lives at risk. The demand by city dwellers for primate pets, along with habitat destruction and fragmentation, exerts a significant pressure on wild populations in southern Mexico. Copyright 2003 Wiley-Liss, Inc.

  9. Lead in human blood and milk from nursing women living near a smelter in Mexico City.

    PubMed

    Namihira, D; Saldivar, L; Pustilnik, N; Carreón, G J; Salinas, M E

    1993-03-01

    Lead levels in breast milk and blood were determined in women living within a 200-m radius of 3 smelters in Mexico City. All samples were analyzed on a Perkin Elmer 460 atomic absorption spectrometer equipped with HGA 2200. The mean blood lead level was 45.88 micrograms/dl (SD 19.88 microgram/dl), and the geometric mean of milk lead level was 2.47 micrograms/100 ml. The correlation coefficient of these two variables was 0.88. Using the mean value of lead found in breast milk, an infant of 5.5 kg would ingest 8.1 micrograms/kg/d in his diet. The daily permissible intake (DPI) established by the World Health Organization (WHO) in 1972 for an adult is 5.0 micrograms/kg/d.

  10. [Population dynamics, urban structure, and production of living space in the metropolitan zone of Mexico City].

    PubMed

    Schteingart, M

    1989-01-01

    "In this article, an attempt is made to account for certain trends in the growth and distribution of the population, and in the structuring of living space in the metropolitan zone of Mexico City.... Among the important conclusions of this essay are those having to do with the huge growth of some political-administrative units and the relation of this phenomenon to the practices followed by private realtors, often articulated with the policies and programs set by the State's housing agencies, as well as those that associate urban growth and expansion with the development of habitational spaces within the so-called 'formal' and 'informal' housing sectors." Data are from Mexican censuses and other official sources. (SUMMARY IN ENG) excerpt

  11. [Use of social marketing to increase water consumption among school-age children in Mexico City].

    PubMed

    Carriedo, Ángela; Bonvecchio, Anabelle; López, Nancy; Morales, Maricruz; Mena, Carmen; Théodore, Florence L; Irizarry, Laura

    2013-01-01

    To increase water consumption in school children in Mexico City through a social marketing intervention. Cluster quasi-experimental design. Intervention of three months in schools, including water provision and designed based on social marketing. Reported changes in attitude, knowledge and behavior were compared pre and post intervention. Children of the intervention group (n=116) increased in 38% (171 ml) water consumption during school time, control group (n=167) decreased its consumption in 21% (140 ml) (p<0.05), according to their reported consumption. In a sub-sample reported consumption of sweetened beverages decreased 437 ml in the IG and 267 ml in the CG (p<0.05). Social marketing and environmental modifications were effective on increasing water consumption among children, strategy that might contribute to mitigate childhood obesity.

  12. Frequency of isolation of Campylobacter from roasted chicken samples from Mexico City.

    PubMed

    Quiñones-Ramírez, E I; Vázquez-Salinas, C; Rodas-Suárez, O R; Ramos-Flores, M O; Rodríguez-Montaño, R

    2000-01-01

    The presence of Campylobacter spp. was investigated in 100 samples of roasted chicken tacos sold in well-established commercial outlets and semisettled street stands in Mexico City. From 600 colonies displaying Campylobacter morphology only 123 isolates were positive. From these isolates, 51 (41%) were identified as C. jejuni, 23 (19%) as C. coli, and 49 (40%) as other species of this genus. All of the 27 positive samples came from one location where handling practices allowed cross-contamination of the cooked product. The results indicate that these ready-to-consume products are contaminated with these bacteria, representing a potential risk for consumers, especially in establishments lacking adequate sanitary measures to prevent cross-contamination.

  13. CO2 variability from in situ and vertical column measurements in Mexico City

    NASA Astrophysics Data System (ADS)

    Baylon, J. L.; Grutter, M.; Stremme, W.; Bezanilla, A.; Plaza, E.

    2014-12-01

    UNAM started a program to measure, among many other atmospheric parameters, greenhouse gas concentrations at six stations in the Mexican territory as part of the "Red Universitaria de Observatorios Atmosfericos", RUOA (www.ruoa.unam.mx). In this work we present recent time series of CO2 measured at the station located in the university campus in Mexico City, and compare them to total vertical columns of this gas measured at the same location. In situ measurements are continuously carried out with a cavity ring-down spectrometer (Picarro Inc., G2401) since July 2014 and the columns are retrieved from solar absorption measurements taken with a Fourier transform infrared spectrometer (Bruker, Vertex 80) when conditions allow. The retrieval method is described and results of the comparison of both techniques and a detailed analysis of the variability of this important greenhouse gas is presented. Simultaneous surface and column CO2 data are useful to constrain models and estimate emissions.

  14. [Gender performativity, medicalization and health in transsexual women in Mexico City].

    PubMed

    Cosme, José Arturo Granados; Ramírez, Pedro Alberto Hernández; Muñoz, Omar Alejandro Olvera

    2017-01-01

    The World Health Organization and the American Psychological Association consider transsexuality a pathology and suggest sex-gender reassignment for the biopsychic adjustment of trans people. Through the discursive analysis of experience, this study describes the processes of medicalization and gender performativity in relation to the health of a group of trans women from Mexico City. For this purpose, a qualitative study was conducted in which 10 semi-structured interviews were carried out in 2015. As part of medicalization, the pathologization of transsexuality generated psychic suffering; on the other hand, sex-gender reassignment also entailed additional risks. It is possible to conclude that in trans women, violence and exclusion constitute the primary experiences explaining their foremost health problems. Therefore, it is suggested that it is necessary for discrimination be reduced and for advancements to be made in safer medical interventions.

  15. [Between the stigma and the law: legal abortion in Mexico City].

    PubMed

    Lamas, Marta

    2014-01-01

    The present contribution is part of a research developed with qualitative social research methods. It offers part of the results attained in a study performed at a clinic belonging to Mexico City´s Government, and explores the effects on staff of the implementation of Legal Pregnancy Termination (ILE, for its initials in Spanish). The results highlights that, besides diminishing health risks in the women who abort, the use of misoprostol prompted assertive attitudes in many women, that reduced the negative effects produced by the stigma of abortion. It also acknowledges the persistence of stigma in the opinions of the health personnel. The empowering of the self-image of women who become subject to this procedure is due to the full exercise of their legal right.

  16. [Infant feeding: a reflection regarding the nursing curricula in Mexico City].

    PubMed

    Salas Valenzuela, Monserrat; Torre Medina-Mora, Pilar; Meza Segura, Citlal

    2014-08-01

    Given the key position of the nursing profession in primary health care, in this article we examine the nursing degree curricula in public institutions in Mexico City to establish whether these programs of study include the topics necessary to implement the current recommendations regarding infant feeding. We perform a documentary analysis that compares the nursing curricula to the two official regulations existing on the subject. In a total of eleven locations, nine public institutions offer undergraduate degrees in nursing. There are seven programs of study in existence, with different structures, course names, and thematic contents among them and all with insufficient and outdated bibliography. We recommend that the programs be made more equivalent, that the bibliography be updated, and that the relevant official standards and international literature be included, so as to better meet the challenges of modernity and globalization in the subject of infant feeding.

  17. Deoxynivalenol and zearalenone in Fusarium-contaminated wheat in Mexico City.

    PubMed

    González-Osnaya, L; Farrés, A

    2011-01-01

    Fusarium spp. invasion causes head blight, a destructive disease in the world's main wheat-growing areas, and deoxynivalenol (DON) and zearalenone (ZEA) contamination in cereal-based products. No data are available on the relationship between Fusarium spp. on commercial wheat samples in Mexico City and the presence of mycotoxins. A total of 30 wheat samples were subject to a PCR method involving genes of the trichothecene and zearalenone biosynthesis pathways to detect the presence of Fusarium. Detection and quantification of DON and ZEA was performed using liquid chromatography coupled to UV detection. PCR indicated the presence of the Tri5 and PKS4 genes in 16.7 and 23.3% of samples, respectively. DON and ZEA contamination was found in 51.2 and 71.4% of samples, respectively, where a positive amplification was obtained. This work presents up-to-date information on mycotoxin contamination in Mexico, where improved contamination/exposure data and firm control/monitoring measures are needed.

  18. Detection of toxigenic Bacillus cereus strains isolated from vegetables in Mexico City.

    PubMed

    Flores-Urbán, Karen A; Natividad-Bonifacio, Iván; Vázquez-Quiñones, Carlos R; Vázquez-Salinas, Carlos; Quiñones-Ramírez, Elsa Irma

    2014-12-01

    Bacillus cereus can cause diarrhea and emetic syndromes after ingestion of food contaminated with it. This ability is due to the production of enterotoxins by this microorganism, these being the hemolysin BL complex, which is involved in the diarrheal syndrome, and cereulide, which is responsible for the emetic syndrome. The detection of genes associated with the production of these toxins can predict the virulence of strains isolated from contaminated food. In this paper, we analyzed 100 samples of vegetables, 25 of each kind (broccoli, coriander, carrot, and lettuce) obtained from different markets in Mexico City and its metropolitan area. B. cereus was isolated in 32, 44, 84, and 68% of the samples of broccoli, carrot, lettuce, and coriander, respectively. The hblA gene (encoding one of the three subunits of hemolysin BL) was amplified in 100% of the B. cereus isolates, and the ces gene (encoding the cereulide) could not be amplified from any of them. This is the first report of B. cereus isolation from the vegetables analyzed in this work and, also, the first report in Mexico of the isolation from vegetables of strains with potential virulence. The results should serve as evidence of the potential risk of consuming these foods without proper treatment.

  19. [Abortion and physicians in training: the opinion of medical students in Mexico City

    PubMed

    González De León Aguirre D; Salinas Urbina AA

    1997-04-01

    This research project explores doctors' views regarding induced abortion. Abortion's penalization in Mexico greatly conditions its relevance as a social and public health problem. Physicians constitute a professional sector that can play an important role in reforming current laws on abortion. As a professional group, they have taken a conservative stance towards abortion. Their attitudes are to a great extent influenced by the medical training they receive. In this article we present results from a survey of 96 medical students from the Universidad Autónoma Metropolitana Xochimilco, in Mexico City. Data were processed with the SPSS program. Simple frequencies show that students have limited knowledge concerning the legal status of abortion and that they tolerate it with restrictions and in limited situations. Women students apparently take a more conservative stance, but statistical analysis with the c-square test did not show significant differences by gender. The article poses the need to modify doctors' training in the reproductive health field, allowing future doctors to acquire a broader view of health problems related to sexuality and reproduction. In the long run, this should also promote a kind of comprehensive health care practice in medical services, thus responding more satisfactorily to women's needs.

  20. Assessment of new vehicles emissions certification standards in the metropolitan area of Mexico City.

    PubMed

    Schifter, I; Díaz, L; López-Salinas, E

    2006-03-01

    Light duty gasoline vehicles account for most of CO hydrocarbons and NOx emissions at the Metropolitan Area of Mexico City (MAMC). In order to ameliorate air pollution from the beginning of 2001, Tier 1 emission standards became mandatory for all new model year sold in the country. Car manufacturers in Mexico do not guarantee the performance of their exhaust emissions systems for a given mileage. The purpose of this study was to assess whether the Tier 1 vehicles will stand the certification values for at least 162000 km with the regular fuel available at the MAMC. Mileage accumulation and deterioration show that certified carbon monoxide emissions will stand for the useful life of the vehicles but in the case of non-methane hydrocarbons will be shorter by 40%, and nitrogen oxides emissions above the standard will be reached at one third of the accumulated kilometers. The effect of gasoline sulfur content, on the current in use Tier 1 vehicles of the MAMC and the impact on the emissions inventory in year 2010 showed that 31000 extra tons of NOx could be added to the inventory caused by the failure of the vehicles to control this pollutant at the useful life of vehicles.

  1. [Prevalence of irritable bowel syndrome in Veracruz City, Mexico: a community-based survey].

    PubMed

    Valerio-Ureña, J; Vásquez-Fernández, F; Jiménez-Pineda, A; Cortázar-Benítez, L F; Azamar-Jácome, A A; Duarte-Velázquez, M E; Torres-Medina, V

    2010-01-01

    Irritable bowel syndrome (IBS) is recognized as the most frequent functional digestive disorder around the world. In Latin America and Mexico there are few studies in order to demonstrate its real prevalence in general population. To determine the prevalence of IBS in general population from Veracruz City Mexico, using the Rome II criteria. Using basic information given by bureau for planning urban services from Veracruz country, a 10% random population sample was obtained. Subjects between 16-80 years old were interviewed using a questionnaire based on Rome II criteria and a visual analogous scale in order to estimate the negative effect of IBS symptoms on daily activities. We interviewed 459 subjects with a median age of 31.2 +/- 13.6 years old detecting 78 subjects (16.9%) with IBS symptoms: 25 males and 53 females (gender prevalence of 11.3% and 22.1%, respectively). 28.2% of them had IBS with diarrhea, 50% had IBS with constipation and 21.8% alternating bowel movements, diarrhea and constipation. Negative effect of IBS symptoms on daily activities was significant. The prevalence of IBS in open population was 16.9% according to Rome II criteria, being higher in those older than 35 years old. Constipation was the predominant pattern. Further studies should evaluate associated factors of these findings.

  2. Solar Activity, Ultraviolet Radiation and Consequences in Birds in Mexico City, 2001- 2002

    NASA Astrophysics Data System (ADS)

    Valdes, M.; Velasco, V.

    2008-12-01

    Anomalous behavior in commercial and pet birds in Mexico City was reported during 2002 by veterinarians at the Universidad Nacional Autonoma de Mexico. This was attributed to variations in the surrounding luminosity. The solar components, direct, diffuse, global, ultraviolet band A and B, as well as some meteorological parameters, temperature, relative humidity, and precipitation, were then analyzed at the Solar Radiation Laboratory. Although the total annual radiance of the previously mentioned radiation components did not show important changes, ultraviolet Band-B solar radiation did vary significantly. During 2001 the total annual irradiance , 61.05 Hjcm² to 58.32 Hjcm², was 1.6 standard deviations lower than one year later, in 2002 and increased above the mean total annual irradiance, to 65.75 Hjcm², 2.04 standard deviations, giving a total of 3.73 standard deviations for 2001-2002. Since these differences did not show up clearly in the other solar radiation components, daily extra-atmosphere irradiance was analyzed and used to calculate the total annual extra-atmosphere irradiance, which showed a descent for 2001. Our conclusions imply that Ultraviolet Band-B solar radiation is representative of solar activity and has an important impact on commercial activity related with birds.

  3. Solar absorption Fourier Transform Infrared spectroscopy applied to detect SO2 plumes above Mexico City

    NASA Astrophysics Data System (ADS)

    Aldana-Vazquez, A.; Stremme, W.; Grutter, M.

    2010-12-01

    There are sources of emissions of sulfur dioxide (SO2) that disperse to the Metropolitan Area of Mexico City (MCMA). The sources can be divided into three categories: a) The active Popocatepetl volcano located 70 km SE from the center of Mexico City, b) the industrial area located approximately 70 km to the and c) other local sources located in the surroundings from the measurement.. Solar absorption infrared spectra are being recorded since 2007 above the campus of the Universidad Nacional Autónoma de México (UNAM, 19.33 N, 99.18 W, 2260 m.a.s.l.). The column of SO2 was retrieved from all the spectra recorded in 2008 with the retrieval code SFIT2. Enhancement of the SO2 column could be identified in different time periods. The origin of the detected SO2 is determined by correlating the SO2 column with a) its surface concentration measured in the surroundings by the monitoring stations from the city’s monitoring network of (RAMA), b) the height of the mixing layer measured at UNAM, and c) meteorological wind data (REDMET, NCEP-NARR, and SMN). The result shows that the extraordinary events are correlated with the mentioned sources, and the analysis confirms prior studies that the plume travels at different altitudes. The plume of the Popocatepetl volcano is transported according to the wind at 5000 m.a.s.l. while emissions from the industrial area northwest of the MCMA are dispersed at lower altitudes within the mixing layer.

  4. Efficient screening for COPD using three steps: a cross-sectional study in Mexico City.

    PubMed

    Franco-Marina, Francisco; Fernandez-Plata, Rosario; Torre-Bouscoulet, Luis; García-Sancho, Cecilia; Sanchez-Gallen, Elisa; Martinez, David; Perez-Padilla, Rogelio

    2014-05-20

    Underdiagnosis of chronic obstructive pulmonary disease (COPD) in primary care can be improved by a more efficient screening strategy. To evaluate a three-step method of screening for COPD consisting of an initial short questionnaire followed by measurement of forced expiratory volume in 1s/forced expiratory volume in 6s (FEV1/FEV6) using an inexpensive pocket spirometer in those with high risk, and diagnostic quality spirometry in those with a low FEV1/FEV6. We analysed two related Mexico City cross-sectional samples. The 2003 Mexico City PLATINO survey (n=542) was used to develop a short questionnaire to determine the risk of COPD and a 2010 survey (n=737) additionally used a pocket spirometer. The discriminatory power of the two instruments was assessed with receiver operator characteristic (ROC) curves using three COPD definitions. The developed COPD scale included two variables from a simple questionnaire and, in ROC analysis, an area under the curve (AUC) between 0.64 and 0.77 was found to detect COPD. The pocket spirometer had an AUC between 0.85 and 0.88 to detect COPD. Using the COPD scale as a first screening step excluded 35-48% of the total population from further testing at the cost of not detecting 8-18% of those with COPD. Using the pocket spirometer and sending those with a FEV1/FEV6<0.80 for diagnostic quality spirometry is very efficient, and substantially improved the positive predictive value at the cost of not detecting one-third of COPD cases. A three-step screening strategy for COPD substantially reduces the need for spirometry testing when only a COPD scale is used for screening.

  5. Relationship between erosive tooth wear and beverage consumption among a group of schoolchildren in Mexico City.

    PubMed

    González-Aragón Pineda, Álvaro Edgar; Borges-Yáñez, Socorro Aída; Irigoyen-Camacho, María Esther; Lussi, Adrian

    2018-05-13

    To assess the association between erosive tooth wear (ETW) and consumption of different kinds of beverages in a group of schoolchildren 11-14 years old in Mexico City. Cross-sectional study in a sample of students (n = 512) in Mexico City. The Basic Erosive Wear Examination (BEWE) was used to quantify ETW. Beverage consumption (BC) was determined using a frequency questionnaire; beverages included pure water, natural fruit juices, milk, hot beverages, and soft drinks. Ordinal logistic regression model was used to evaluate the association between the presence of ETW and BC. In total, 45.7% of the schoolchildren showed an initial loss of surface texture (BEWE = 1) and 18.2% a distinct defect involving loss of dental tissue (BEWE ≥ 2) in at least one tooth. For each glass (350 ml) of milk/week, the odds of not having erosive wear (BEWE = 0) versus having an initial loss of surface texture (BEWE = 1) or of having an initial loss of surface texture versus the presence of a defect involving the loss of dental tissue (BEWE ≥ 2) decreased 4% (OR = 0.96, 95% CI 0.93-0.99, p = 0.008); for each portion of sweet carbonated beverage consumed (350 ml), the odds increased 3% (OR = 1.03, 95% CI 1.001-1.07, p = 0.046). The intake of milk and milk-based products could be a dietary means of helping prevent ETW, especially if their consumption could replace sweet carbonated drink consumption. Knowing the impact of beverage consumption on ETW helps to provide suitable recommendations for the prevention and control of ETW in order to promote tooth longevity.

  6. An evaluation of the hybrid car technology for the Mexico Mega City

    NASA Astrophysics Data System (ADS)

    Jazcilevich, Aron D.; Reynoso, Agustin Garcia; Grutter, Michel; Delgado, Javier; Ayala, Ulises Diego; Lastra, Manuel Suarez; Zuk, Miriam; Oropeza, Rogelio Gonzalez; Lents, Jim; Davis, Nicole

    The introduction of hybrid electric vehicle (HEV) technology in the private car fleet of Mexico City is evaluated in terms of private costs, energy, public health and CO 2 emission benefits. In addition to constructing plausible scenarios for urban expansion, emission, car fleet, and fuel consumption for year 2026 and comparing them with a 2004 base case, a time series is built to obtain accumulated economic benefits. Experimental techniques were used to build a vehicle library for a car simulator that included a Prius 2002, chosen as the HEV technology representative for this work. The simulator is used to estimate the emissions and fuel consumption of the car fleet scenarios. In the context of an urban scenario for year 2026, a complex air quality model obtains the concentrations of criterion pollutants corresponding to these scenarios. Using a technology penetration model, the hybridized fleet starts unfolding in year 2009 reaching to 20% in 2026. In this year, the hybridized fleet resulted in reductions of about 10% of CO 2 emissions, and yielded reductions in daytime mean concentrations of up to 7% in ozone and 3.4% in PM 2.5 compared to the 2004 base case. These reductions are concentrated in the densely populated areas of Mexico City. By building a time series of costs and benefits it is shown that, depending on fuel prices and using a 5% return rate, positive accumulated benefits (CO 2 benefits + energy benefits + public health benefits - private costs) will start generating in year 2015 reaching between 2.8 and 4.5 billion US Dlls in 2026. Another modernized private fleet consisting exclusively of Tier I and II cars did not yield appreciable results, signaling that a change in private car technology towards HEV's is needed to obtain significant accumulated benefits.

  7. Chemical characterization of extractable water soluble matter associated with PM10 from Mexico City during 2000.

    PubMed

    Gutiérrez-Castillo, M E; Olivos-Ortiz, M; De Vizcaya-Ruiz, A; Cebrián, M E

    2005-11-01

    We report the chemical composition of PM10-associated water-soluble species in Mexico City during the second semester of 2000. PM10 samples were collected at four ambient air quality monitoring sites in Mexico City. We determined soluble ions (chloride, nitrate, sulfate, ammonium, sodium, potassium), ionizable transition metals (Zn, Fe, Ti, Pb, Mn, V, Ni, Cr, Cu) and soluble protein. The higher PM(10) levels were observed in Xalostoc (45-174 microg m(-3)) and the lowest in Pedregal (19-54 microg m(-3)). The highest SO2 average concentrations were observed in Tlalnepantla, NO2 in Merced and O3 and NO(x) in Pedregal. The concentration range of soluble sulfate was 6.7-7.9 and 19-25.5 microg m(-3) for ammonium, and 14.8-29.19 for soluble V and 3.2-7.7 ng m(-3) for Ni, suggesting a higher contribution of combustion sources. PM-associated soluble protein levels varied between 0.038 and 0.169 mg m(-3), representing a readily inhalable constituent that could contribute to adverse outcomes. The higher levels for most parameters studied were observed during the cold dry season, particularly in December. A richer content of soluble metals was observed when they were expressed by mass/mass units rather than by air volume units. Significant correlations between Ni-V, Ni-SO4(-2), V-SO4(-2), V-SO2, Ni-SO2 suggest the same type of emission source. The variable soluble metal and ion concentrations were strongly influenced by the seasonal meteoclimatic conditions and the differential contribution of emission sources. Our data support the idea that PM10 mass concentration by itself does not provide a clear understanding of a local PM air pollution problem.

  8. On the Chemical Characterization of Organic Matter in Rain at Mexico City.

    NASA Astrophysics Data System (ADS)

    Montero-Martinez, G.; Andraca-Ayala, G. L.; Hernández-Nagay, D. P.; Mendoza-Trejo, A.; Rivera-Arellano, J.; Rosado-Abon, A.; Roy, P. D.

    2016-12-01

    The chemical composition of the aerosol plays a central role in atmospheric processes and has influence on the hydrological cycle. Clouds form through the nucleation of water vapor on certain atmospheric aerosol particles, called cloud condensation nuclei (CCN). Also, precipitating particles scavenge some other aerosol particles on their way to the surface. Atmospheric particles are a mixture of organic and inorganic materials, both soluble and insoluble in water. Aerosol chemical characterization indicates a larger variety of compounds in urban areas respect to other regions. Thus, chemical composition of rainwater may represent an important aspect for estimating atmospheric air pollution. It has been recognized that organic species present in aerosol particles are important in the formation of cloud droplets. Therefore, the information about the organic compounds in precipitation samples may be helpful to understand their effects on the formation of clouds and rain, as well as their sources. Organic acids are ubiquitous components of aerosols and have been identified in precipitation water. In this work, preliminary results of the content of soluble organic (neutral and acidic) matter in rainwater samples collected in Mexico City during 2015 will be presented. The organic compounds content was performed by using an ionic chromatographic methodology with gradient elution; so the total amount was evaluated as the sum of four fractions: neutral/basic, mono-, bi-, and poly-acid compounds. The outcomes suggest that most of the amount of organic substances soluble in water is contained by the neutral/basic and mono-acid fractions. Regarding the total amount of water soluble organic compounds, the rain samples collected in Mexico City are in agreement with some others reported for large urban areas.

  9. Platinum in PM2.5 of the metropolitan area of Mexico City.

    PubMed

    Morton-Bermea, Ofelia; Amador-Muñoz, Omar; Martínez-Trejo, Lida; Hernández-Álvarez, Elizabeth; Beramendi-Orosco, Laura; García-Arreola, María Elena

    2014-10-01

    The increase in platinum (Pt) in the airborne particulate matter with size ≤2.5 µm (PM2.5) in urban environments may be interpreted as result of the abrasion and deterioration of automobile catalyst. Nowadays, about four million vehicles in Mexico City use catalytic converters, which means that their impact should be considered. In order to evaluate the contribution of Pt to environmental pollution of the metropolitan area of Mexico City (MAMC), airborne PM2.5 was collected at five different sites in the urban area (NW, NE, C, SW, SE) in 2011 during April (dry-warm season), August (rainy season) and December (dry-cold season). Analytical determinations were carried out using a ICP-MS with a collision cell and kinetic energy discrimination. The analytical and instrument performance was evaluated with standard road dust reference material (BCR-723). Median Pt concentration in the analyzed particulate was is 38.4 pg m(-3) (minimal value 1 pg m(-3) maximal value 79 pg m(-3)). Obtained Pt concentrations are higher than those reported for other urban areas. Spatial variation shows that SW had Pt concentration significantly higher than NW and C only. Seasonal variation shows that Pt median was higher in rainy season than in both dry seasons. A comparison of these results with previously reported data of PM10 from 1991 and 2003 in the same studied area shows a worrying increase in the concentration of Pt in the air environment of MAMC.

  10. [Food preferences and nutritional status in school-age children living in Mexico City].

    PubMed

    Sánchez-García, Rocío; Reyes-Morales, Hortensia; González-Unzaga, Marco Aurelio

    Childhood is a basic period for the development of habits and their continuation during the course of life. The objective of this study was to identify food preferences and their variations according to the nutritional status in school-age children living in Mexico City. A cross-sectional study was carried out including 1465 school-age children attending eight public elementary schools in Mexico City. Children were asked to complete a questionnaire regarding their preferences to 70 selected different foods. Anthropometric measurements were also carried out. Parents of the children provided sociodemographic information. For each food, the preference was evaluated using a Likert scale. Frequencies were calculated for the total sample and for different nutritional status levels. Median age of children was 9 years old. Forty-eight percent of the children were overweight or obese. The most preferred foods were fruits, pizzas, flavored milk, and French fries. The least preferred foods were vegetables, whole-grain cereals, fish, meat, and panela cheese. Plain water (72%) and sugar-sweetened beverages (71%) had a high level of preference. There was no preference variation according to nutritional status. Food preference patterns of school-age children are a risk for unhealthy food consumption as well as for the increase in obesity prevalence in this population. Interventions focused on the promotion of a healthy food environment are necessary, aimed at improving food preferences from early childhood. Copyright © 2014 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

  11. Lung function growth in children with long-term exposure to air pollutants in Mexico City.

    PubMed

    Rojas-Martinez, Rosalba; Perez-Padilla, Rogelio; Olaiz-Fernandez, Gustavo; Mendoza-Alvarado, Laura; Moreno-Macias, Hortensia; Fortoul, Teresa; McDonnell, William; Loomis, Dana; Romieu, Isabelle

    2007-08-15

    Although short-term exposure to air pollution has been associated with acute, reversible lung function decrements, the impact of long-term exposure has not been well established. To evaluate the association between long-term exposure to ozone (O(3)), particulate matter less than 10 mum in diameter (PM(10)), and nitrogen dioxide (NO(2)) and lung function growth in Mexico City schoolchildren. A dynamic cohort of 3,170 children aged 8 years at baseline was followed from April 23, 1996, through May 19, 1999. The children attended 39 randomly selected elementary schools located near 10 air quality monitoring stations and were visited every 6 months. Statistical analyses were performed using general linear mixed models. After adjusting for acute exposure and other potential confounding factors, deficits in FVC and FEV(1) growth over the 3-year follow-up period were significantly associated with exposure to O(3), PM(10), and NO(2). In multipollutant models, an interquartile range (IQR) increase in mean O(3) concentration (IQR, 11.3 ppb) was associated with an annual deficit in FEV(1) of 12 ml in girls and 4 ml in boys, an IQR range (IQR, 36.4 microg/m(3)) increase in PM(10) with an annual deficit in FEV(1) of 11 ml in girls and 15 ml in boys, and an IQR range (IQR, 12.0 ppb) increase in NO(2) with an annual deficit in FEV(1) of 30 ml in girls and 25 ml in boys. We conclude that long-term exposure to O(3), PM(10), and NO(2) is associated with a deficit in FVC and FEV(1) growth among schoolchildren living in Mexico City.

  12. Assessment of water supply as an ecosystem service in a rural-urban watershed in southwestern Mexico City.

    PubMed

    Jujnovsky, Julieta; González-Martínez, Teresa Margarita; Cantoral-Uriza, Enrique Arturo; Almeida-Leñero, Lucia

    2012-03-01

    Studies from the ecosystem services perspective can provide a useful framework because they allow us to fully examine the benefits that humans obtain from socio-ecological systems. Mexico City, the second largest city in the world, has faced severe problems related to water shortages, which have worsened due to increasing population. Demand for space has forced changes in land cover, including covering areas that are essential for groundwater recharge. The city has 880 km(2) of forest areas that are crucial for the water supply. The Magdalena River Watershed was chosen as a model because it is a well-preserved zone within Mexico City and it provides water for the population. The general aim of this study was to assess the ecosystem service of the water supply in the Magdalena River Watershed by determining its water balance (SWAT model) and the number of beneficiaries of the ecosystem services. The results showed that the watershed provides 18.4 hm(3) of water per year. Baseflow was dominant, with a contribution of 85%, while surface runoff only accounted for 15%. The zone provides drinking water to 78,476 inhabitants and could supply 153,203 potential beneficiaries. This work provides an example for understanding how ecosystem processes determine the provision of ecosystem services and benefits to the population in a rural-urban watershed in Mexico City.

  13. Utilizing Tropospheric Emission Spectrometer (TES) Special Observations to Study Air Quality Over Megacities: A Case Study of Mexico City

    NASA Astrophysics Data System (ADS)

    Osterman, G. B.; Neu, J. L.; Cady-Pereira, K.; Fu, D.; Payne, V.; Pfister, G.

    2016-12-01

    Since the beginning of 2013, the Tropospheric Emission Spectrometer (TES) on the NASA Aura spacecraft has been making special "transect" observations over 19 large cities across the globe. In all there are over 50 transect observations of each city, allowing for studying the chemistry of the troposphere during different seasons and differing atmospheric conditions. The cities that have been observed include, Beijing, Delhi and Mexico City. In addition, the TES group at JPL has been developing new data products using combined radiances from other satellite instruments. They have produced an ozone data product using a combination of TES and Ozone Monitoring Instrument (OMI) radiances. There has also been progress in creating an ozone product from combining OMI and Atmospheric Infrared Sounder (AIRS) radiances using the TES retrieval framework. This product offers the possibility of better spatial coverage than the TES or TES/OMI products. We have selected an observation from October 13, 2013 over Mexico City for doing a case study where high values of ozone were seen in the lower troposphere in retrievals from TES and TES/OMI. Other trace gases measured by TES, carbon monoxide, methanol, and formic acid were also enhanced over the city. TES was also able to capture downwind conditions where the trace gases were no longer enhanced except for formic acid and peroxyacetyl nitrate which showed elevated values. We will utilize trajectory analysis, the TES data as well as combined TES-OMI retrievals, the new combined AIRS-OMI retrievals of ozone to examine this case in more detail to understand possible broader scale effects of Mexico City pollution. Model results will be utilized to provide further context in understanding the atmospheric conditions being studied. We feel the TES special observations of megacities will provide an opportunity to study the effects of local sources versus broader regional sources on pollutions of these large cities.

  14. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

    PubMed Central

    2011-01-01

    Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also

  15. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City.

    PubMed

    Diaz-Badillo, Alvaro; Bolling, Bethany G; Perez-Ramirez, Gerardo; Moore, Chester G; Martinez-Munoz, Jorge P; Padilla-Viveros, America A; Camacho-Nuez, Minerva; Diaz-Perez, Alfonso; Beaty, Barry J; Munoz, Maria de Lourdes

    2011-05-09

    Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The

  16. Application of an extension of the MAI method to the Acapulco City, Mexico

    NASA Astrophysics Data System (ADS)

    Contreras, M.; Aguirre, J.

    2001-12-01

    The site effects and the source parameters, are inverted from a Fourier displacement spectra of seismograms that are corrected by geometrical spreading and regional attenuation valid for south center of Mexico(Ordaz and Singh, 1992). We used Genetic Algorithms (GA) to perform the non-linear inversion, like in the MAI method (Moya et al., 2000) . The GA have proved to produce better results than other traditional methods which are frequently trapped in a local minimum. GA is a method that mimics the evolution laws in living creatures. The best individuals reproduce and develop themselves with every generation. In our case each individual correspond to one source and the genes correspond to the source parameters. As in nature, the best source remain and are improved with each iteration. We assume that the site effect at each station are the same independently of the earthquake, because of that we can search for the combination of sources that can produce the smaller standard deviation of the estimated site effects from the different Fourier displacement earthquake spectra. Then we use the obtained site effects to generate a Fourier displacement spectra of an earthquake scenario. With this, we are able to compute the response spectra by means of random vibration theory (Reinoso et al., 1990). We apply this method to four stations located in the Acapulco City, Mexico, that recorded four earthquakes with epicenter located in the Guerrero Subduction Zone. The site effect estimated for one of the stations, called ACAZ, shows a good agreement with the estimated by Chávez-García et al. (1994) using spectral ratios between the ACAZ station and a rock reference site. Also we compare the response spectra from other earthquake, obtained by the former method and the response spectra computed using the acceleration record. We find an acceptable correlation between them. Chávez-García, J. Cuenca y M. Cárdenas (1994), "Estudio complementario de efectos de sitio en Acapulco

  17. Exhaust Emissions from Gasoline- and LPG-Powered Vehicles Operating at the Altitude of Mexico City.

    PubMed

    Gamas, Erick D; Diaz, Luis; Rodriguez, René; López-Salinas, E; Schifter, Isaac; Ontiveros, Luis

    1999-10-01

    Unburned hydrocarbons (HCs), carbon monoxide (CO), and oxides of nitrogen (NO x ) are the compounds regulated as pollutants by an environmental standard in the Metropolitan Area of Mexico City (MAMC). The main fuel used in vehicular transportation is gasoline, and the use of liquefied petroleum gas (LPG) is now an alternative as low emission technology to decrease the environmental impact of transportation operations. The environmental impact of commercial gasoline consumption in the Valley of Mexico was estimated by on-road and FTP-75 testing of three formulations of gasoline (one leaded [octane 81] and two unleaded [one octane 87 and one octane 93]). A fleet of 30 vehicles was used: 10 were chosen that had pre-1990 technology, while 12 were 1991-1996 vehicles equipped with fuel injection, catalytic converters, and air/ fuel ratio control technology. The remaining eight vehicles were high-performance new model vehicles (1995-1996) equipped with the newest technology available for pollution control. Fifteen vehicles in the fleet were also tested for the effect of changing from leaded to unleaded gasoline. Three different LPG formulations were tested using three vehicles representative of the LPG-powered fleet in the MAMC. Two gasoline-to-LPG conversion certified commercial systems were evaluated following the BAR-90 and the HOT-505 procedures. Emissions corresponding to the high-octane (premium) gasoline showed a 15% higher contribution to HCs with a 6% lower reactivity than the 87 octane gasoline; the HCs in the exhaust for premium gasoline are mainly isoparaffins. When the vehicles were tested on the road at high speeds, an average 3% increase in mileage was obtained when vehicles were switched from leaded to unleaded gasoline, while a 5% increase in mileage was observed when vehicles were switched from 87 octane to premium gasoline. The tests of LPG formulations indicated that a change in composition from 60% vol of propane to 85.5% vol reduces levels of HCs and

  18. Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

    NASA Astrophysics Data System (ADS)

    Vargas, Carlos; Ortega-Guerrero, Adrián

    A regional lacustrine aquitard covers the main aquifer of the metropolitan area of Mexico City. The aquitard's hydraulic conductivity (K') is fundamental for evaluating the natural protection of the aquifer against a variety of contaminants present on the surface and its hydraulic response. This study analyzes the distribution and variation of K' in the plains of Chalco, Texcoco and Mexico City (three of the six former lakes that existed in the Basin of Mexico), on the basis of 225 field-permeability tests, in nests of existing piezometers located at depths of 2-85 m. Tests were interpreted using the Hvorslev method and some by the Bouwer-Rice method. Results indicate that the distribution of K' fits log-Gaussian regression models. Dominant frequencies for K' in the Chalco and Texcoco plains range between 1E-09 and 1E-08 m/s, with similar population means of 1.19E-09 and 1.7E-09 m/s, respectively, which are one to two orders of magnitude higher than the matrix conductivity. In the Mexico City Plain the population mean is near by one order of magnitude lower; K'=2.6E-10 m/s. The contrast between the measured K' and that of the matrix is attributed to the presence of fractures in the upper 25-40 m, which is consistent with the findings of previous studies on solute migration in the aquitard. Un imperméable régional d'origine lacustre recouvre le principal aquifère de la zone urbaine de la ville de Mexico. La conductivité hydraulique K' de cet imperméable est fondamentale pour évaluer la protection naturelle de l'aquifère, contre les différents contaminants présents en surface, et sa réponse hydraulique. Cette étude analyse et les variations de K' dans les plaines de Chalco, Texcoco et Mexico (trois des six anciens lacs qui existaient dans le Bassin de Mexico), sur la base de 225 essais de perméabilité sur le terrain, réalisés en grappes dans des piézomètres existants entre 2 et 85 m de profondeur. Les essais ont été interprétés avec la m

  19. A representative survey of indoor radon in the sixteen regions in Mexico City.

    PubMed

    Espinosa, G; Gammage, R B

    2003-01-01

    Mexico City, also called Federal District, covers an area of 1504 km(2), and has more than 8 million inhabitants. It is located more than 2200 m above sea level in a zone of high seismic activity, and founded on an ancient lake. At present it is one of the most crowded and contaminated cities in the world, with thermal inversions. Chemical contaminants and aerosol particles in the environmental air are high most of the year. Due to these geological, environmental and socioeconomic conditions, Federal District presents very peculiar characteristics, which are important for understanding the distribution and measurements of indoor radon concentration. In this work the results of 3 year (1998-2000) measurements of indoor radon levels in the Federal District are presented. For the detector distribution and measurements, the actual political administrative divisions of the Federal District, consisting of 16 very well defined zones, was used. Nuclear track detection methodology was selected for the measurement, with a passive device close-end-cup system with CR-39 (Lantrack) polycarbonate as the detection material, with one step chemical etching, following a very well established protocol developed at the Instituto de Física, UNAM. Calibration was carried out at the Oak Ridge National Laboratory, and verification at the Instituto de Física chamber. The results show that the arithmetical mean values of the indoor radon concentration for each region of the Federal District follow a non-homogenous distribution.

  20. New Magnetic and Geochemical Results on Topsoils of the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Martínez-Pichar, E.; Soler-Arechalde, A. M.; Morton, O.; Hernandez, E.; Lozano-Santa-Cruz, R.; Gonzalez, G.; Beramendi, L.; Urrutia-Fucugauchi, J. H.

    2008-05-01

    The Metropolitan Area of Mexico city is a region well known for intense industrial and commercial activity. The potential sources of the heavy metal pollutants are assumed to be petroleum processing, production of iron material, manufacturing, coal combustion, commercial and automobile exhaust. New samples were collected from industrial, roadside, residential and public parks in the urban areas around the city and added to two previous field campaigns (2003 and 2005). Localities selected for the study represent, presumably, different heavy metal pollution levels and sources. At each sampling point, the top 2 cm layer of the soil profile was collected with a stainless steel trowel and stored in a plastic bag. The elements Fe, Cu and Zn concentrations were determined by EDXRF (Philips PW1400 apparatus) on bulk- sample pressed, boric-acid backed pellets. Metal concentrations of Pb, Ni, Cr, and V were analyzed by ICP-MS with a VG Elemental PQ3 instrument. Magnetic mineralogy in bulk soil samples was investigated by low-field susceptibility using a Kappabridge KLY2. Remanent magnetizations (ARM and IRM) and Hysteresis loops of micro samples had been carried out at room temperature. Bivariate analysis on different ratios of magnetic parameters was employed to characterize the pollution sources.

  1. Data Acquisition for Land Subsidence Control

    NASA Astrophysics Data System (ADS)

    Zhu, Y.; Balke, K.

    2009-12-01

    For controlling land subsidence caused by groundwater over-exploitation, loading of engineered structures, mining and other anthropogenic activities in this fast changing world, a large variety of different data of various scales of concerning areas are needed for scientific study and administrative operational purposes. The economical, social and environmental impacts of anthropogenic land subsidence have long been recognized by many scientific institutions and management authorities based on results of monitoring and analysis at an interdisciplinary level. The land subsidence information systems composed of the surface and subsurface monitoring nets (monitoring and development wells, GPS stations and other facilities) and local data processing centers as a system management tool in Shanghai City was started with the use of GPS technology to monitor land subsidence in 1998. After years of experiences with a set of initiatives by adopting adequate countermeasures, the particular attention given to new improved methodologies to monitor and model the process of land subsidence in a simple and timely way, this is going to be promoted in the whole Yangtze River Delta region in China, where land subsidence expands in the entire region of urban cluster. The Delta land subsidence monitoring network construction aims to establish an efficient and coordinated water resource management system. The land subsidence monitoring network records "living history" of land subsidence, produces detailed scheduled reports and environmental impact statements. For the different areas with local factors and site characteristics, parallel packages need to be designed for predicting changes, land sensitivity and uncertainty analysis, especially for the risk analysis in the rapid growth of megacities and urban areas. In such cases, the new models with new types of local data and the new ways of data acquisition provide the best information for the decision makers for their mitigating

  2. Levels, Composition and Sources of PM in the Mexico City Metropolitan Area During the MILAGRO Campaign

    NASA Astrophysics Data System (ADS)

    Querol, X.; Pey, J.; Minguillon, M. C.; Perez, N.; Alastuey, A.; Moreno, T.; Bernabe, R.; Blanco, S.; Cardenas, B.

    2007-05-01

    Particle air pollution in urban agglomerations comes mostly from anthropogenic sources, mainly traffic, industrial processes, energy production, domestic and residential emissions, construction, but also a minor contribution from natural sources may be expected (bioaerosols, soil dust, marine aerosol). Once emitted into the atmosphere, this complex mixture of pollutants may be transformed as a function of the ambient conditions and the interaction among the different PM components, and also between PM components and gaseous pollutants. This system is especially complex in mega-cities due to the large emission volumes of PM components and gaseous precursors, the high variability and broad distribution of emission sources, and the possible long range transport of the polluted air masses. Speciation studies help to identify major sources of PM components with the end objective of applying plans and programs for PM pollution abatement. In this framework, concentration levels and compositions of particulate matter (PM2.5, PM10 and TSP) have been measured simultaneously at two sites in the Mexico City Metropolitan Area (T0 and CENICA) and at one site 50 km away from Mexico City (T1) during the MILAGRO campaign (1st to 31st March 2006). Spatial and time (day and night) variations have been analysed. Coarse fraction levels were higher at T1 than at CENICA and T0, contrary to what was expected. This was due to the important soil re-suspension at T1, contributing significantly to the crustal load. Moreover, crustal levels were higher during daytime than during nights at all sites, while some secondary compounds (sulphate and ammonium) presented an opposite trend. Regarding trace elements, levels of Pb, Zn and Cd were higher at T0 than at CENICA and T1, probably due to traffic contribution. Arsenic levels did not show a clear pattern, being alternatively higher at CENICA and T0. Two intense episodes of Hg particulate have been recorded, more noticeable at T1 than at the urban

  3. An emission processing system for air quality modelling in the Mexico City metropolitan area: Evaluation and comparison of the MOBILE6.2-Mexico and MOVES-Mexico traffic emissions.

    PubMed

    Guevara, M; Tena, C; Soret, A; Serradell, K; Guzmán, D; Retama, A; Camacho, P; Jaimes-Palomera, M; Mediavilla, A

    2017-04-15

    This article describes the High-Elective Resolution Modelling Emission System for Mexico (HERMES-Mex) model, an emission processing tool developed to transform the official Mexico City Metropolitan Area (MCMA) emission inventory into hourly, gridded (up to 1km 2 ) and speciated emissions used to drive mesoscale air quality simulations with the Community Multi-scale Air Quality (CMAQ) model. The methods and ancillary information used for the spatial and temporal disaggregation and speciation of the emissions are presented and discussed. The resulting emission system is evaluated, and a case study on CO, NO 2 , O 3 , VOC and PM 2.5 concentrations is conducted to demonstrate its applicability. Moreover, resulting traffic emissions from the Mobile Source Emission Factor Model for Mexico (MOBILE6.2-Mexico) and the MOtor Vehicle Emission Simulator for Mexico (MOVES-Mexico) models are integrated in the tool to assess and compare their performance. NO x and VOC total emissions modelled are reduced by 37% and 26% in the MCMA when replacing MOBILE6.2-Mexico for MOVES-Mexico traffic emissions. In terms of air quality, the system composed by the Weather Research and Forecasting model (WRF) coupled with the HERMES-Mex and CMAQ models properly reproduces the pollutant levels and patterns measured in the MCMA. The system's performance clearly improves in urban stations with a strong influence of traffic sources when applying MOVES-Mexico emissions. Despite reducing estimations of modelled precursor emissions, O 3 peak averages are increased in the MCMA core urban area (up to 30ppb) when using MOVES-Mexico mobile emissions due to its VOC-limited regime, while concentrations in the surrounding suburban/rural areas decrease or increase depending on the meteorological conditions of the day. The results obtained suggest that the HERMES-Mex model can be used to provide model-ready emissions for air quality modelling in the MCMA. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Seroepidemiology of Toxoplasma gondii in pregnant women in Aguascalientes City, Mexico: a cross-sectional study.

    PubMed

    Alvarado-Esquivel, Cosme; Terrones-Saldívar, María Del Carmen; Hernández-Tinoco, Jesús; Muñoz-Terrones, María Daniela Enriqueta; Gallegos-González, Roberto Oswaldo; Sánchez-Anguiano, Luis Francisco; Reyes-Robles, Martha Elena; Jaramillo-Juárez, Fernando; Liesenfeld, Oliver; Estrada-Martínez, Sergio

    2016-07-01

    We determined the seroprevalence and correlates of Toxoplasma gondii infection in pregnant women in Aguascalientes City, Mexico. A cross-sectional survey. Pregnant women were enrolled in the central Mexican city of Aguascalientes. We studied 338 pregnant women who attended prenatal care in 3 public health centres. Women were examined for IgG/IgM antibodies to T. gondii by using commercially available enzyme immunoassays, and an avidity test. Multiple analyses were used to determine the association of T. gondii seropositivity with the characteristics of the pregnant women. Of the 338 pregnant women studied, 21 (6.2%) had IgG antibodies to T. gondii, and 1 (4.8%) of them was also positive for IgM antibodies to T. gondii. Avidity of IgG antibodies to T. gondii was high in the IgM-positive sample. Logistic regression analysis of sociodemographic, behavioural and housing variables showed that T. gondii seropositivity was associated with white ethnicity (OR=149.4; 95% CI 10.8 to 2054.1; p<0.01), not washing hands before eating (OR=6.41; 95% CI 1.73 to 23.6; p=0.005) and use of latrine (OR=37.6; 95% CI 4.63 to 306.31; p=0.001). Results demonstrate that pregnant women in Aguascalientes City have a low seroprevalence of T. gondii infection. However, this low prevalence indicates that most pregnant women are at risk for a primary infection. Factors associated with T. gondii exposure found in this study, including food hygiene, may be useful to determine preventive measures against T. gondii infection and its sequelae. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  5. High seroprevalence of Toxoplasma gondii infection in inmates: A case control study in Durango City, Mexico.

    PubMed

    Alvarado-Esquivel, C; Hernández-Tinoco, J; Sánchez-Anguiano, L F; Ramos-Nevárez, A; Cerrillo-Soto, S M; Sáenz-Soto, L; Liesenfeld, O

    2014-03-01

    The seroprevalence of infection with the parasite Toxoplasma gondii and the association with risk factors has not been determined in inmates. Through a case-control study, 166 inmates from a state correctional facility in Durango City, Mexico and 166 age- and gender-matched non-incarcerated subjects were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. Seroprevalence of anti-T. gondii IgG antibodies was higher in inmates (35, 21.1%) than in controls (14, 8.4%) (OR = 2.90; 95% CI: 1.43-5.94; P = 0.001). Anti-T. gondii IgM antibodies were detected in two (1.2%) inmates and in seven (4.2%) controls (P = 0.17). Multivariate analysis of socio-demographic, incarceration, and behavioral characteristics of inmates revealed that T. gondii seropositivity was associated with being born out of Durango State (OR = 3.91; 95% CI: 1.29-11.79; P = 0.01). In addition, T. gondii seroprevalence was higher (P = 0.03) in inmates that had suffered from injuries (17/56: 30.4%) than those without such history (18/110: 16.4%). The seroprevalence of T. gondii infection in inmates in Durango City is higher than the seroprevalences found in the general population in the same city, indicating that inmates may represent a new risk group for T. gondii infection. Further research on T. gondii infection in inmates is needed.

  6. High seroprevalence of Toxoplasma gondii infection in inmates: A case control study in Durango City, Mexico

    PubMed Central

    Hernández-Tinoco, J.; Sánchez-Anguiano, L. F.; Ramos-Nevárez, A.; Cerrillo-Soto, S. M.; Sáenz-Soto, L.; Liesenfeld, O.

    2014-01-01

    Purpose The seroprevalence of infection with the parasite Toxoplasma gondii and the association with risk factors has not been determined in inmates. Through a case-control study, 166 inmates from a state correctional facility in Durango City, Mexico and 166 age- and gender-matched non-incarcerated subjects were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. Results Seroprevalence of anti-T. gondii IgG antibodies was higher in inmates (35, 21.1%) than in controls (14, 8.4%) (OR = 2.90; 95% CI: 1.43–5.94; P = 0.001). Anti-T. gondii IgM antibodies were detected in two (1.2%) inmates and in seven (4.2%) controls (P = 0.17). Multivariate analysis of socio-demographic, incarceration, and behavioral characteristics of inmates revealed that T. gondii seropositivity was associated with being born out of Durango State (OR = 3.91; 95% CI: 1.29–11.79; P = 0.01). In addition, T. gondii seroprevalence was higher (P = 0.03) in inmates that had suffered from injuries (17/56: 30.4%) than those without such history (18/110: 16.4%). Conclusions The seroprevalence of T. gondii infection in inmates in Durango City is higher than the seroprevalences found in the general population in the same city, indicating that inmates may represent a new risk group for T. gondii infection. Further research on T. gondii infection in inmates is needed. PMID:24678408

  7. Georadar Archaeological Prospection at the Historical Center of the Merida City, Yucatan, Mexico.

    NASA Astrophysics Data System (ADS)

    Barba, L.; Ortiz, A.; Blancas, J.; Ligorred, J.

    2007-05-01

    This paper shows the results of the georadar archaeological prospection carried out by the Laboratorio de Prospección Arqueologica from the Instituto de Investigaciones Antropologicas (IIA) of the Universidad Nacional Autonoma de Mexico (UNAM) verifing the archaeological and historical information recovered by the Departamento de Patrimonio Arqueologico y Natural del Municipio (DPANM) del Ayuntamiento de Merida en el Centro Histerico de la Ciudad de Merida under a joint project. The Historical Center of Merida has been classified as a "zone of high patrimonial value" after the topographic data and the historical documents recovered showed a long-term occupation, non interrupted since pre-Columbian times, when T Ho was the great capital of the northern region of the Maya area. For the rehabilitation program of the Historical Center of Merida has been a great priority to verify the existence of archaeological remains, pre-Columbian or colonial, under the present streets, gardens and plazas that could be damaged during the public infrastructure works. In order to prevent any damage to the patrimony a large georadar study was carried out pulling 200 and 400 MHz antennas of the GSSI SIR System 2 for 16500 m of the city streets, focusing in the areas where infrastructure works were imminent. After the analysis of the radar data it was possible to build up a map with the location of the most noticeable archaeological remains under the pavement of the streets that confirmed many of the topographic and documental proposed places. As a final result, by the first time a city government has available information to take present urban decisions, while preventing the damage to the archaeological patrimony of the same city.

  8. Extreme magnitude earthquakes and their economical impact: The Mexico City case

    NASA Astrophysics Data System (ADS)

    Chavez, M.; Mario, C.

    2005-12-01

    The consequences (estimated by the human and economical losses) of the recent occurrence (worldwide) of extreme magnitude (for the region under consideration) earthquakes, such as the 19 09 1985 in Mexico (Ritchter magnitude Ms 8.1, moment magnitude Mw 8.01), or the one in Indonesia of the 26 12 2004 (Ms 9.4, Mw 9.3), stress the importance of performing seismic hazard analysis that, specifically, incorporate this possibility. Herewith, we present and apply a methodology, based on plausible extreme seismic scenarios and the computation of their associated synthetic accelerograms, to estimate the seismic hazard on Mexico City (MC) stiff and compressible surficial soils. The uncertainties about the characteristics of the potential finite seismic sources, as well as those related to the dynamic properties of MC compressible soils are taken into account. The economic consequences (i.e. the seismic risk = seismic hazard x economic cost) implicit in the seismic coefficients proposed in MC seismic Codes before (1976) and after the 1985 earthquake (2004) are analyzed. Based on the latter and on an acceptable risk criterion, a maximum seismic coefficient (MSC) of 1.4g (g = 9.81m/s2) of the elastic acceleration design spectra (5 percent damping), which has a probability of exceedance of 2.4 x 10-4, seems to be appropriate for analyzing the seismic behavior of infrastructure located on MC compressible soils, if extreme Mw 8.5 subduction thrust mechanism earthquakes (similar to the one occurred on 19 09 1985 with an observed, equivalent, MSC of 1g) occurred in the next 50 years.

  9. Contributors to ozone episodes in three US/Mexico border twin-cities.

    PubMed

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma.

  10. Longitudinal study of microbial diversity and seasonality in the Mexico City metropolitan area water supply system.

    PubMed

    Mazari-Hiriart, Marisa; López-Vidal, Yolanda; Ponce-de-León, Sergio; Calva, Juan José; Rojo-Callejas, Francisco; Castillo-Rojas, Gonzalo

    2005-09-01

    In the Mexico City metropolitan area (MCMA), 70% of the water for 18 million inhabitants is derived from the Basin of Mexico regional aquifer. To provide an overview of the quality of the groundwater, a longitudinal study was conducted, in which 30 sites were randomly selected from 1,575 registered extraction wells. Samples were taken before and after chlorine disinfection during both the rainy and dry seasons (2000-2001). Microbiological parameters (total coliforms, fecal coliforms, streptococci, and Vibrio spp.), the presence of Helicobacter pylori, and physicochemical parameters, including the amount of trihalomethanes (THMs), were determined. Although microorganisms and inorganic and organic compounds were evident, they did not exceed current permissible limits. Chlorine levels were low, and the bacterial counts were not affected by chlorine disinfection. Eighty-four bacterial species from nine genera normally associated with fecal contamination were identified in water samples. H. pylori was detected in at least 10% of the studied samples. About 40% of the samples surpassed the THM concentration allowed by Mexican and U.S. regulations, with levels of chloroform being high. The quality of the water distributed to the MCMA varied between the rainy and dry seasons, with higher levels of pH, nitrates, chloroform, bromodichloromethane, total organic carbon, and fecal streptococci during the dry season. This study showed that the groundwater distribution system is susceptible to contamination and that there is a need for a strict, year-round disinfection strategy to ensure adequate drinking-water quality. This situation in one of the world's megacities may reflect what is happening in large urban centers in developing countries which rely on a groundwater supply.

  11. Sociodemographic differences among HIV-positive and HIV-negative recently pregnant women in Mexico City

    PubMed Central

    Aguilar-Zapata, Daniel; Piñeirúa-Menéndez, Alicia; Volkow-Fernández, Patricia; Rodríguez-Zulueta, Patricia; Ramos-Alamillo, Ubaldo; Cabrera-López, Teresita; Martin-Onraet, Alexandra

    2017-01-01

    Abstract National HIV preventive programs in Mexico focus on high-risk groups that do not consider women, apart from prenatal screening. Nonetheless, the epidemic in women is growing, and there is a need to better understand sociodemographic factors in women living with HIV (WLH). We performed a case–control study in Mexico City, including HIV+ and HIV− women with a recent pregnancy to compare their sociodemographic characteristics and describe the circumstances of diagnosis in HIV+ women, as well as prenatal screening frequency in both groups. Fifty cases and 102 controls were interviewed. HIV+ women were more frequently the only economic support of the family (20% vs 0%, P < .0001). Thirty-eight percent of cases had their first pregnancy at ≤18 years, versus 16% of controls (odds ratio 2.47, 95% confidence interval 1.07–5.72, P = .03); 16% of cases had lived in the street; 6% reported transactional sex, versus none of the controls (P < .0001). In the multivariate analysis, there was strong evidence of an association between HIV infection and age at the time of the interview, history of sexually transmitted diseases, substance abuse, history of violence, and civil status. Only 6% of controls were tested for HIV during prenatal follow-up. WLH in this study faced important social vulnerability. Targeting women living in these social contexts might increase early diagnosis and could tailor HIV prevention strategies. Prenatal coverage needs to be improved and should represent a national priority. PMID:28682879

  12. [Culturally constructed meanings for consumption of sweetened beverages among schoolchildren in Mexico City].

    PubMed

    Théodore, Florence; Bonvecchio, Anabelle; Blanco, Ilian; Irizarry, Laura; Nava, Alma; Carriedo, Angela

    2011-10-01

    Demonstrate the importance of the cultural factors that currently motivate Mexican children to consume sweetened beverages and examine their implications for the design of programs for the promotion of healthy lifestyles. A qualitative phenomenological study involving nine peer interviews and four discussion groups was conducted among children aged 9 and 10 years in four public schools in southern Mexico City. The interviews employed nine photographs of beverages that are available in schools and homes. The aim was to identify the culinary rules associated with the consumption of sweetened beverages and the different views held by the children about the beverages. The complete interviews and group discussions were recorded and transcribed. Matrixes were developed for analysis of the subject categories identified during the study. The analysis was based on "continuous comparison" of the statements made by boys and girls, and among students from the four schools. Two main sociocultural elements, constructed in a given cultural framework, partly explain the children's current consumption patterns. The first, the nearly nonexistent concept that water is for drinking, with water consumption being limited to engagement in physical activity, in contrast to the wide range of circumstances and occasions found for the consumption of a sweetened beverage. Secondly, the identification of three principles that appear to underlie beverage consumption: the combination of salty food with sweet drinks, the important role of sweetened beverages at social events, and the close association between water consumption and the thirst induced by physical effort. The results show the importance of considering the role of socially significant elements in dietary practices and the need to also consider these elements when designing interventions for schoolchildren. It is also important to change the children's current views about what they drink, guiding and encouraging them to think of water

  13. Longitudinal Study of Microbial Diversity and Seasonality in the Mexico City Metropolitan Area Water Supply System

    PubMed Central

    Mazari-Hiriart, Marisa; López-Vidal, Yolanda; Ponce-de-León, Sergio; Calva, Juan José; Rojo-Callejas, Francisco; Castillo-Rojas, Gonzalo

    2005-01-01

    In the Mexico City metropolitan area (MCMA), 70% of the water for 18 million inhabitants is derived from the Basin of Mexico regional aquifer. To provide an overview of the quality of the groundwater, a longitudinal study was conducted, in which 30 sites were randomly selected from 1,575 registered extraction wells. Samples were taken before and after chlorine disinfection during both the rainy and dry seasons (2000-2001). Microbiological parameters (total coliforms, fecal coliforms, streptococci, and Vibrio spp.), the presence of Helicobacter pylori, and physicochemical parameters, including the amount of trihalomethanes (THMs), were determined. Although microorganisms and inorganic and organic compounds were evident, they did not exceed current permissible limits. Chlorine levels were low, and the bacterial counts were not affected by chlorine disinfection. Eighty-four bacterial species from nine genera normally associated with fecal contamination were identified in water samples. H. pylori was detected in at least 10% of the studied samples. About 40% of the samples surpassed the THM concentration allowed by Mexican and U.S. regulations, with levels of chloroform being high. The quality of the water distributed to the MCMA varied between the rainy and dry seasons, with higher levels of pH, nitrates, chloroform, bromodichloromethane, total organic carbon, and fecal streptococci during the dry season. This study showed that the groundwater distribution system is susceptible to contamination and that there is a need for a strict, year-round disinfection strategy to ensure adequate drinking-water quality. This situation in one of the world's megacities may reflect what is happening in large urban centers in developing countries which rely on a groundwater supply. PMID:16151096

  14. Aerosol climatology over the Mexico City basin: Characterization of optical properties

    NASA Astrophysics Data System (ADS)

    Carabali, Giovanni; Estévez, Héctor Raúl; Valdés-Barrón, Mauro; Bonifaz-Alfonzo, Roberto; Riveros-Rosas, David; Velasco-Herrera, Víctor Manuel; Vázquez-Gálvez, Felipe Adrián

    2017-09-01

    Climatology of Aerosol Optical Depth (AOD), Single Scattering Albedo (SSA), and aerosol particle-size distribution were analyzed using a 15-year (1999-2014) dataset from AErosol RObotic NETwork (AERONET) observations over the Mexico City (MC) basin. The atmosphere over this site is dominated by two main aerosol types, represented by urban/industrial pollution and biomass-burning particles. Due to the specific meteorological conditions within the basin, seasons are usually classified into three as follows: Dry Winter (DW) (November-February); Dry Spring (DS) (March-April), and the RAiny season (RA) (May-October), which are mentioned throughout this article. Using a CIMEL sun photometer, we conducted continuous observations over the MC urban area from January 1999 to December 2014. Aerosol Optical Depth (AOD), Ångström exponent (α440-870), Single Scattering Albedo (SSA), and aerosol particle-size distribution were derived from the observational data. The overall mean AOD500 during the 1999-2014 period was 0.34 ± 0.07. The monthly mean AOD reached a maximal value of 0.49 in May and a minimal value of 0.27 in February and March. The average α440-870 value for the period studied was 1.50 ± 0.16. The monthly average of α440-870 reached a minimal value of 1.32 in August and a maximal value of 1.61 in May. Average SSA at 440 nm was 0.89 throughout the observation period, indicating that aerosols over Mexico City are composed mainly of absorptive particles. Concentrations of fine- and coarse-mode aerosols over MC were highest in DS season compared with other seasons, especially for particles with radii measuring between 0.1 and 0.2 μm. Results from the Spectral De-convolution Algorithm (SDA) show that fine-mode aerosols dominated AOD variability in MC. In the final part of this article, we present a classification of aerosols in MC by using the graphical method proposed by Gobbi et al. (2007), which is based on the combined analysis of α and its spectral curvature

  15. Spectral Optical Properties of the Polluted Atmosphere of Mexico City (Spring-Summer 1992)

    NASA Technical Reports Server (NTRS)

    Vasilyev, O. B.; Contreras, A. Leyva; Valazquez, A. Muhlia; Peralta-Fabi, R.; Ivlev, L. S.; Kovalenko, A. P.; Vasilyev, A. V.; Jukov, V. M.; Welch, Ronald M.

    1995-01-01

    A joint Mexican, Russian, and American research effort has been initiated to develop new methods to remotely sense atmospheric parameters using ground-based, aircraft, and satellite observations. As a first step in this program, ground-based spectrophotometric measurements of the direct solar radiation have been obtained for the extremely polluted Mexico City atmosphere for the period of April-June 1992. These observations were made at more than 1300 channels in the spectral range of 0.35-0.95 microns. In the UltraViolet (UV) portions of the spectrum (e.g., 0.35 microns), aerosol optical thicknesses were found to range between 0.6 and 1.2; in the visible portion of the spectrum (e. g., 0.5 microns) they ranged from 0.5 to 0.8; and in the Near-Infrared (NIR) spectra (e.g., 0.85 micron), values of 0.3 - 0.5 were found. Applying a Spectral Optical Depth (SOD) model of tau(lambda) = C + A(lambda(sup -varies as), values of 1.55 less than varies as less than 1.85 were obtained for polluted, cloudless days, with values of 1.25 less than varies as less than 1.60 on days with haze. The aerosol particles in the polluted Mexico City atmosphere were found to be strongly absorbing, with a single-scattering albedo of 0.7 - 0.9 in the UV, 0.6 - 0.8 in the visible portion of the spectrum, and 0.4 - 0.7 in the NIR. These values are possibly consistent with a high soot concentration, contributed both by vehicular traffic and heavy industry. Analysis of the measured aerosol SOD using the optical parameters of an urban aerosol model pemiits the concentration of aerosol particles to be estimated in the vertical column; a maximum value of 3 x 10(exp 9) 1/sq cm was found. This concentration of aerosol particles exceeds that found in most other regions of the globe by at least an order of magnitude. Near the ground the aerosol size distributions measured using an optical particle counter were found to be strongly multimodal.

  16. Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Miranda, G. P.; Gaffney, J. S.; Marley, N. A.

    2007-05-01

    Four photoacoustic spectrometers (PAS) for aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The four sites included: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP); a suburban site at the Technological University of Tecamac; a rural site at "La Biznaga" ranch; and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. A similar campaign was held in Las Vegas, Nevada, USA in January-February, 2003. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. Comparisons with TSI nephelometer scattering at the T0 site will be presented. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of

  17. An air pollution modeling study using three surface coverings near the New International Airport of Mexico City.

    PubMed

    Jazcilevich, Arón D; García, Agustín R; Ruiz-Suárez, Luis-Gerardo

    2003-10-01

    The dry lakebed of what once was the lake of Texcoco is the location selected for the New International Airport of Mexico City. This project will generate an important urban development near the airport with regional implications on air quality. Using a prognostic air quality model, the consequences of photochemical air pollution in the metropolitan area of Mexico City resulting from three possible coverings for the areas of the lakebed that are not occupied by the runway and terminal building are investigated. These coverings are desert, grassland, and water and occupy an area of 63 km2. This study is based on a representative high pollution episode. In addition to reducing the emission of primary natural particles, the water covering generates a land-water breeze capable of maintaining enough ventilation to reduce pollutant concentrations over a localized region of the metropolitan area and may enhance the wind speed on the coasts of the proposed lake.

  18. Approach to the characterization of the airborne organic matter (benzene soluble) in the atmosphere of Mexico City

    SciTech Connect

    Bravo, H.; Baez, A.P.

    1961-01-01

    Three areas of Mexico City were chosen from which to obtain samples of aromatic airborne particles. The samples were analyzed in order to have a broad idea of the composition of the material. The downtown area contained the highest concentration of organic benzene soluble material in the airborne particles, with the highest concentrations during the winter months. A combined sample (Ciudad Universitaria and Tacuba) was analyzed and gave the following figures of benzene soluble material in mg/g: fluoranthene - 160; pyrene - 210; benzo(a)anthracene - 47; benzo(a)pyrene - 82; benzo(e)pyrene - 150; benzo(g,h,i)perylene - 340; coronene - 160. A moremore » complete study is recommended in order to establish the actual parameters of the organic content in Mexico City's atmosphere.« less

  19. Space geodesy: subsidence and flooding in New Orleans.

    PubMed

    Dixon, Timothy H; Amelung, Falk; Ferretti, Alessandro; Novali, Fabrizio; Rocca, Fabio; Dokka, Roy; Sella, Giovanni; Kim, Sang-Wan; Wdowinski, Shimon; Whitman, Dean

    2006-06-01

    It has long been recognized that New Orleans is subsiding and is therefore susceptible to catastrophic flooding. Here we present a new subsidence map for the city, generated from space-based synthetic-aperture radar measurements, which reveals that parts of New Orleans underwent rapid subsidence in the three years before Hurricane Katrina struck in August 2005. One such area is next to the Mississippi River-Gulf Outlet (MRGO) canal, where levees failed during the peak storm surge: the map indicates that this weakness could be explained by subsidence of a metre or more since their construction.

  20. Ozone exposure and daily mortality in Mexico City: a time-series analysis.

    PubMed

    Loomis, D P; Borja-Aburto, V H; Bangdiwala, S I; Shy, C M

    1996-10-01

    Daily death counts in Mexico City were examined in relation to ambient ozone levels during 1990-1992 for the purpose of investigating the acute, irreversible effects of air pollution, with emphasis on ozone exposure. Air pollution data were obtained from nine monitoring stations operated by the Departamento del Distrito Federal. Mortality data were provided by the Instituto Nacional de Estadística, Geografía, e Informática. Increases in numbers of deaths were positively associated with elevated air pollution levels on the same day and on the previous day. The magnitude of the increases was small but statistically significant, after Poisson regression models were used to adjust for temperature and long-term trends. In models using data for a single pollutant, the "crude" ratio for total mortality associated with an increase of 100 parts per billion (ppb)* in one-hour maximum ozone concentration was 1.029 (95% CI 1.015, 1.044). A moving average of ozone showed a stronger association (rate ratio [RR] = 1.048, 95% CI 1.025, 1.070), and excess mortality (an increase in the number of deaths, relative to the average on days with low pollution levels) was more evident for persons over 65 years of age. Separate analyses of the effect of elevated ozone for different areas of the city showed similar results, but they were not statistically significant. Other pollutants also were related to mortality. The RR was 1.075 (95% CI 0.984, 1.062) per 100-ppb increase for sulfur dioxide and 1.049 (95% CI 1.030, 1.067) per 100 micrograms/m3 increase in total suspended particulates (TSP) when these pollutants were considered in separate models. However, when all three pollutants were considered simultaneously, only TSP remained associated with mortality, indicating excess mortality of 5% per 100 micrograms/m3 increase [RR = 1.052, 95% CI 1.034, 1.072]. The excess mortality associated with TSP is consistent with that observed in other cities in America and Europe. This study provides

  1. Lost Hills Subsidence Animation

    NASA Image and Video Library

    2012-02-06

    This frame from an animation depicts ground subsidence resulting from the extraction of oil. The oil fields are located near the community of Lost Hills, California, approximately 100 km northwest of Bakersfield.

  2. Human and remote sensing data to investigate the frontiers of urbanization in the south of Mexico City.

    PubMed

    Rodriguez Lopez, Juan Miguel; Heider, Katharina; Scheffran, Jürgen

    2017-04-01

    The data presented here were originally collected for the article "Frontiers of Urbanization: Identifying and Explaining Urbanization Hot Spots in the South of Mexico City Using Human and Remote Sensing" (Rodriguez et al. 2017) [4]. They were divided into three databases (remote sensing, human sensing, and census information), using a multi-method approach with the goal of analyzing the impact of urbanization on protected areas in southern Mexico City. The remote sensing database was prepared as a result of a semi-automatic classification, dividing the land cover data into urban and non-urban classes. The second data set details an alternative view of the phenomena of urbanization by concentrating on illegal settlements in the conservation zone. It was based on voluntary complaints about environmental and land use offences filed at the Procuraduria Ambiental y del Ordenamiento Territorial del Distrito Federal (PAOT), which is a governmental entity responsible for reviewing and processing grievances on five basic topics: illegal land use, deterioration of green areas, waste, noise/vibrations, and animals. Anyone can file a PAOT complaint by phone, electronically, or in person. The complaint ends with a resolution, act of conciliation, or recommendation for action by other actors, such as the police or health office. The third data about unemployment was extracted from Mexico׳s National Census 2010 database available via public access.

  3. Overview of the 2006 MILAGRO Campaign in Mexico City: Transport and Transformation of Emissions from a Megacity

    NASA Astrophysics Data System (ADS)

    Molina, L.; MILAGRO Science Team

    2009-04-01

    Megacities (metropolitan areas with population over 10 million) and large urban centers present a major challenge for the global environment. Population growth, increasing motorization and industrialization have resulted in a higher demand for energy, greater use of fossil fuels, and more emission of pollutants into the atmosphere. As a result, air pollution has become not only one of the central environmental problems of the century, but also presents serious consequences to human health and ecosystems and economic costs to society. MILAGRO (Megacity Initiative: Local and Global Research Observations) is the first international effort to study the impact of air pollutants generated and exported by megacity. The Mexico City Metropolitan Area (MCMA) - one of the largest megacities in the world - was selected as the initial case study for MILAGRO. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, complemented by meteorological forecasting and numerical simulations. Together, these research observations have provided the most comprehensive characterization of Mexico City's urban and regional air pollution that will take years to analyze and evaluate fully. Initial analysis of the data is focused on understanding meteorology, emissions, urban and regional photochemistry, aerosol evolution and radiative effects - spanning the urban to regional scale transition. Many interesting aspects of atmospheric chemistry in and near the MCMA are emerging and have already added significantly to our understanding of the chemical and physical properties of the city's reactive atmosphere and the regional impacts. The information can be useful for decision-makers in Mexico in developing air quality management strategies as well as provide insights to air pollution problems in

  4. Complete Genome Sequence of Paenibacillus larvae MEX14, Isolated from Honey Bee Larvae from the Xochimilco Quarter in Mexico City.

    PubMed

    Peréz de la Rosa, D; Pérez de la Rosa, J J; Cossio-Bayugar, R; Miranda-Miranda, E; Lozano, L; Bravo-Díaz, M A; Rocha-Martínez, M K; Sachman-Ruiz, B

    2015-08-27

    Paenibacillus larvae strain MEX14 is a facultative anaerobic endospore-forming bacterium that infects Apis mellifera larvae. Strain MEX14 was isolated from domestic bee larvae collected in a backyard in Mexico City. The estimated genome size was determined to be 4.18 Mb, and it harbors 4,806 protein coding genes (CDSs). Copyright © 2015 Peréz de la Rosa et al.

  5. Popular health education and propaganda in times of peace and war in Mexico city, 1890s-1920s.

    PubMed

    Agostoni, Claudia

    2006-01-01

    Health education and propaganda acquired importance during the late 19th and early 20th centuries in Mexico City, as physicians, hygienists, and schoolteachers attempted to teach the principles of public health to a culturally and socially heterogeneous urban population.I explore the organization of the Popular Hygiene Exhibition of 1910 and the importance of health education before and after the armed phase of the Mexican Revolution, and why children and the indigenous populations became the main recipients of health education programs.

  6. Knowledge and technology transfer to improve the municipal solid waste management system of Durango City, Mexico.

    PubMed

    Valencia-Vázquez, Roberto; Pérez-López, Maria E; Vicencio-de-la-Rosa, María G; Martínez-Prado, María A; Rubio-Hernández, Rubén

    2014-09-01

    As society evolves its welfare level increases, and as a consequence the amount of municipal solid waste increases, imposing great challenges to municipal authorities. In developed countries, municipalities have established integrated management schemes to handle, treat, and dispose of municipal solid waste in an economical and environmentally sound manner. Municipalities of developing and transition countries are not exempted from the challenges involving municipal solid waste handling, but their task is not easy to accomplish since they face budget deficits, lack of knowledge, and deficiencies in infrastructure and equipment. In the northern territory of Mexico, the municipality of Durango is facing the challenge of increased volumes of waste with a lack of adequate facilities and infrastructure. This article analyses the evolution of the municipal solid waste management of Durango city, which includes actions such as proper facilities construction, equipment acquisition, and the implementation of social programmes. The World Bank, offering courses to municipal managers on landfill operation and waste management, promoted the process of knowledge and technology transfer. Thereafter, municipal authorities attended regional and some international workshops on waste management. In addition they followed suggestions of international contractors and equipment dealers with the intention to improve the situation of the waste management of the city. After a 15-year period, transfer of knowledge and technology resulted in a modern municipal solid waste management system in Durango municipality. The actual system did not reach the standard levels of an integrated waste management system, nevertheless, a functional evaluation shows clear indications that municipality actions have put them on the right pathway. © The Author(s) 2014.

  7. Using Acceleration Records as Diffuse Fields for Tomography of the Valley of Mexico City: Synthetic Results

    NASA Astrophysics Data System (ADS)

    Baena, M.; Perton, M.; Molina-Villegas, J. C.; Sanchez-Sesma, F. J.

    2013-12-01

    In order to improve the understanding of the seismic response of Mexico City Valley, we have proposed to perform a tomography study of the seismic wave velocities. For that purpose, we used a collection of acceleration seismograms (corresponding to earthquakes with magnitudes ranging from 4.5 to 8.1 and various epicentral distances to the City) recorded since 1985 in 83 stations distributed across the Valley. The H/V spectral ratios (obtained from average autocorrelations) strongly suggest these movements belong to a 3D generalized diffuse field. Thus, we interpret that cross-correlations between the signals of station pairs are proportional to the imaginary part of the corresponding Green function. Finally, the dispersion curves are constructed from the Green function which lead to the tomography. Other tomographies have already been made around the world using either the seismic coda or seismic noise. We used instead the ensemble of many earthquakes from distant sources that have undergone multiple scattering by the heterogeneities of the Earth and assume the wave fields are equipartitioned. The purpose of the present study is to describe the different steps of the data processing by using synthetic models. The wave propagation within an alluvial basin is simulated using the Indirect Boundary Element Method (IBEM) in 2D configuration for the propagation of P and SV waves. The theoretical Green function for a station pair is obtained by placing a unit force at one station and a receiver at the other. The valley illumination is composed by incoming waves which are simulated using distant independent sources and several diffractors. Data process is validated by the correct retrieval the theoretical Green function. We present here the in-plane Green function for the P-SV case and show the dispersion curves constructed from the cross-correlations compared with analytic results for a layer over a half-space. ACKNOWLEDGEMENTS. This study is partially supported by AXA

  8. The New MAX-DOAS Network in Mexico City for Trace Gas Detection

    NASA Astrophysics Data System (ADS)

    Arellano, E. J.; Krüger, A.; Rivera, C. I.; Stremme, W.; Friedrich, M. M.; Grutter, M.

    2014-12-01

    Atmospheric studies in large cities are of great relevance since pollution affects air quality and human health. We have designed and built instruments based on the Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique and established a network in strategic sites within the Mexico City metropolitan area. Four instruments are now in operation with the aim to study the variability and spatial distribution of key pollutants, which will bring new insight in the current knowledge of transport patterns, emissions as well as frequency and origin of extraordinary events. The instruments measure UV/visible spectra of the sky at different elevation angles in the 280 nm to 510 nm wavelength region along one axis. Currently, 36 measurements constitute a full scan performed from west until East direction (-90 to +90°). The scanning unit, which is installed outdoors, holds a small telescope and the motor control unit. Light is transmitted via an optical fiber to the main box, which holds a compact USB spectrometer and the main control electronics. The spectrometer is accurately temperature controlled and all the spectra of each scan, together with elevation angle and other parameters, are recorded on a compact PC. Post processing of these data with the QDOAS software results in slant column densities (SCD) of the atmospheric gases. This information is then converted to vertical profiles through a process described in a companion presentation. Preliminary results will be presented for formaldehyde, fitted in the region 324-360 nm. The data obtained is useful for the comparison with satellite data for example OMI.

  9. Analysis and modeling of extreme temperatures in several cities in northwestern Mexico under climate change conditions

    NASA Astrophysics Data System (ADS)

    García-Cueto, O. Rafael; Cavazos, M. Tereza; de Grau, Pamela; Santillán-Soto, Néstor

    2014-04-01

    The generalized extreme value distribution is applied in this article to model the statistical behavior of the maximum and minimum temperature distribution tails in four cities of Baja California in northwestern Mexico, using data from 1950-2010. The approach used of the maximum of annual time blocks. Temporal trends were included as covariates in the location parameter (μ), which resulted in significant improvements to the proposed models, particularly for the extreme maximum temperature values in the cities of Mexicali, Tijuana, and Tecate, and the extreme minimum temperature values in Mexicali and Ensenada. These models were used to estimate future probabilities over the next 100 years (2015-2110) for different time periods, and they were compared with changes in the extreme (P90th and P10th) percentiles of maximum and minimum temperature scenarios for a set of six general circulation models under low (RCP4.5) and high (RCP8.5) radiative forcings. By the end of the twenty-first century, the scenarios of the changes in extreme maximum summer temperature are of the same order in both the statistical model and the high radiative scenario (increases of 4-5 °C). The low radiative scenario is more conservative (increases of 2-3 °C). The winter scenario shows that minimum temperatures could be less severe; the temperature increases suggested by the probabilistic model are greater than those projected for the end of the century by the set of global models under RCP4.5 and RCP8.5 scenarios. The likely impacts on the region are discussed.

  10. Mexican Seismic Alert System's SAS-I algorithm review considering strong earthquakes felt in Mexico City since 1985

    NASA Astrophysics Data System (ADS)

    Cuellar Martinez, A.; Espinosa Aranda, J.; Suarez, G.; Ibarrola Alvarez, G.; Ramos Perez, S.; Camarillo Barranco, L.

    2013-05-01

    The Seismic Alert System of Mexico (SASMEX) uses three algorithms for alert activation that involve the distance between the seismic sensing field station (FS) and the city to be alerted; and the forecast for earthquake early warning activation in the cities integrated to the system, for example in Mexico City, the earthquakes occurred with the highest accelerations, were originated in the Pacific Ocean coast, whose distance this seismic region and the city, favors the use of algorithm called Algorithm SAS-I. This algorithm, without significant changes since its beginning in 1991, employs the data that generate one or more FS during P wave detection until S wave detection plus a period equal to the time employed to detect these phases; that is the double S-P time, called 2*(S-P). In this interval, the algorithm performs an integration process of quadratic samples from FS which uses a triaxial accelerometer to get two parameters: amplitude and growth rate measured until 2*(S-P) time. The parameters in SAS-I are used in a Magnitude classifier model, which was made from Guerrero Coast earthquakes time series, with reference to Mb magnitude mainly. This algorithm activates a Public or Preventive Alert if the model predicts whether Strong or Moderate earthquake. The SAS-I algorithm has been operating for over 23 years in the subduction zone of the Pacific Coast of Mexico, initially in Guerrero and followed by Oaxaca; and since March 2012 in the seismic region of Pacific covering the coasts among Jalisco, Colima, Michoacan, Guerrero and Oaxaca, where this algorithm has issued 16 Public Alert and 62 Preventive Alerts to the Mexico City where its soil conditions increase damages by earthquake such as the occurred in September 1985. This work shows the review of the SAS-I algorithm and possible alerts that it could generate from major earthquakes recordings detected by FS or seismometers near the earthquakes, coming from Pacific Ocean Coast whose have been felt in Mexico

  11. What Does Latin American Social Medicine Do When It Governs? The Case of the Mexico City Government

    PubMed Central

    Laurell, Asa Cristina

    2003-01-01

    Latin American social medicine (LASM) emerged as a movement in the 1970s and played an important role in the Brazilian health care reform of the 1980s, both of which focused on decentralization and on health care as a social right. The dominant health care reform model in Latin America has included a market-driven, private subsystem for the insured and a public subsystem for the uninsured and the poor. In contrast, the Mexico City government has launched a comprehensive policy based on social rights and redistribution of resources. A universal pension for senior citizens and free medical services are financed by grants, eliminating routine government corruption and waste. The Mexico City policy reflects the influence of Latin American social medicine. In this article, I outline the basic traits of LASM and those of the prevailing health care reform model in Latin America and describe the Mexico City social and health policy, emphasizing the influence of LASM in values, principles, and concrete programs. PMID:14652327

  12. Statistical persistence of air pollutants (O3,SO2,NO2 and PM10) in Mexico City

    NASA Astrophysics Data System (ADS)

    Meraz, M.; Rodriguez, E.; Femat, R.; Echeverria, J. C.; Alvarez-Ramirez, J.

    2015-06-01

    The rescaled range (R / S) analysis was used for analyzing the statistical persistence of air pollutants in Mexico City. The air-pollution time series consisted of hourly observations of ozone, nitrogen dioxide, sulfur dioxide and particulate matter obtained at the Mexico City downtown monitoring station during 1999-2014. The results showed that long-range persistence is not a uniform property over a wide range of time scales, from days to months. In fact, although the air pollutant concentrations exhibit an average persistent behavior, environmental (e.g., daily and yearly) and socio-economic (e.g., daily and weekly) cycles are reflected in the dependence of the persistence strength as quantified in terms of the Hurst exponent. It was also found that the Hurst exponent exhibits time variations, with the ozone and nitrate oxide concentrations presenting some regularity, such as annual cycles. The persistence dynamics of the pollutant concentrations increased during the rainy season and decreased during the dry season. The time and scale dependences of the persistence properties provide some insights in the mechanisms involved in the internal dynamics of the Mexico City atmosphere for accumulating and dissipating dangerous air pollutants. While in the short-term individual pollutants dynamics seems to be governed by specific mechanisms, in the long-term (for monthly and higher scales) meteorological and seasonal mechanisms involved in atmospheric recirculation seem to dominate the dynamics of all air pollutant concentrations.

  13. Diabetes and hypertension care among male prisoners in Mexico City: exploring transition of care and the equivalence principle.

    PubMed

    Silverman-Retana, Omar; Servan-Mori, Edson; Lopez-Ridaura, Ruy; Bautista-Arredondo, Sergio

    2016-07-01

    To document the performance of diabetes and hypertension care in two large male prisons in Mexico City. We analyzed data from a cross-sectional study carried out during July-September 2010, including 496 prisoners with hypertension or diabetes in Mexico City. Bivariate and multivariable logistic regressions were used to assess process-of-care indicators and disease control status. Hypertension and diabetes prevalence were estimated on 2.1 and 1.4 %, respectively. Among prisoners with diabetes 22.7 % (n = 62) had hypertension as comorbidity. Low achievement of process-of-care indicators-follow-up visits, blood pressure and laboratory assessments-were observed during incarceration compared to the same prisoners in the year prior to incarceration. In contrast to nonimprisoned diabetes population from Mexico City and from the lowest quintile of socioeconomic status at the national level, prisoners with diabetes had the lowest performance on process-of-care indicators. Continuity of care for chronic diseases, coupled with the equivalence of care principle, should provide the basis for designing chronic disease health policy for prisoners, with the goal of consistent transition of care from community to prison and vice versa.

  14. Land use regression models to assess air pollution exposure in Mexico City using finer spatial and temporal input parameters.

    PubMed

    Son, Yeongkwon; Osornio-Vargas, Álvaro R; O'Neill, Marie S; Hystad, Perry; Texcalac-Sangrador, José L; Ohman-Strickland, Pamela; Meng, Qingyu; Schwander, Stephan

    2018-05-17

    The Mexico City Metropolitan Area (MCMA) is one of the largest and most populated urban environments in the world and experiences high air pollution levels. To develop models that estimate pollutant concentrations at fine spatiotemporal scales and provide improved air pollution exposure assessments for health studies in Mexico City. We developed finer spatiotemporal land use regression (LUR) models for PM 2.5 , PM 10 , O 3 , NO 2 , CO and SO 2 using mixed effect models with the Least Absolute Shrinkage and Selection Operator (LASSO). Hourly traffic density was included as a temporal variable besides meteorological and holiday variables. Models of hourly, daily, monthly, 6-monthly and annual averages were developed and evaluated using traditional and novel indices. The developed spatiotemporal LUR models yielded predicted concentrations with good spatial and temporal agreements with measured pollutant levels except for the hourly PM 2.5 , PM 10 and SO 2 . Most of the LUR models met performance goals based on the standardized indices. LUR models with temporal scales greater than one hour were successfully developed using mixed effect models with LASSO and showed superior model performance compared to earlier LUR models, especially for time scales of a day or longer. The newly developed LUR models will be further refined with ongoing Mexico City air pollution sampling campaigns to improve personal exposure assessments. Copyright © 2018. Published by Elsevier B.V.

  15. What does Latin Aamerican social medicine do when it governs? The case of the Mexico City government.

    PubMed

    Laurell, Asa Cristina

    2003-12-01

    Latin American social medicine (LASM) emerged as a movement in the 1970s and played an important role in the Brazilian health care reform of the 1980s, both of which focused on decentralization and on health care as a social right. The dominant health care reform model in Latin America has included a market-driven, private subsystem for the insured and a public subsystem for the uninsured and the poor. In contrast, the Mexico City government has launched a comprehensive policy based on social rights and redistribution of resources. A universal pension for senior citizens and free medical services are financed by grants, eliminating routine government corruption and waste. The Mexico City policy reflects the influence of Latin American social medicine. In this article, I outline the basic traits of LASM and those of the prevailing health care reform model in Latin America and describe the Mexico City social and health policy, emphasizing the influence of LASM in values, principles, and concrete programs.

  16. Tuberculosis and systemic lupus erythematosus: a case-control study in Mexico City.

    PubMed

    Torres-González, Pedro; Romero-Díaz, Juanita; Cervera-Hernández, Miguel Enrique; Ocampo-Torres, Mario; Chaires-Garza, Luis Gerardo; Lastiri-González, Ernesto Alejandro; Atisha-Fregoso, Yemil; Bobadilla-Del-Valle, Miriam; Ponce-de-León, Alfredo; Sifuentes-Osornio, José

    2018-04-20

    To determine, among systemic lupus erythematosus patients, factors associated with active tuberculosis. We performed a case-control study, in a tertiary-care center in Mexico City. We defined cases as systemic lupus erythematosus patients with active tuberculosis and matched them 1:1 with systemic lupus erythematosus patients without tuberculosis (controls) by age, date of systemic lupus erythematosus diagnosis, and disease duration. We analyzed clinical variables, lupus disease activity (SLEDAI-2K), and accumulated damage (SLICC/ARC-DI). We performed a nonconditional logistic regression to determine factors associated with tuberculosis. We identified 72 tuberculosis cases among systemic lupus erythematosus patients, 58% were culture confirmed. Thirty-three percent (24/72) were pulmonary only, 47.2% (34/72) extrapulmonary only, and 19.4% both. After adjustment for age, gender, and socioeconomic status, SLEDAI-2K and SLICC/ARC-DI, a 1-year cumulative dose of prednisone ≥ 3 g (odds ratios (OR), 18.85; 95% confidence interval (95% CI), 6.91-51.45) was associated with tuberculosis, and the antimalarial treatment was protective (OR, 0.13; 95% CI, 0.04-0.36). Among systemic lupus erythematosus patients, cumulative dose of prednisone is associated with tuberculosis. Further research is required to elucidate the protective effect of antimalarial drugs for tuberculosis. Preventive strategies must be implemented in patients at risk.

  17. Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

    SciTech Connect

    Lewandowski, P.A.; Kleinman, L.; Eichinger, W. E.

    On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar system made a North-South transect through the Mexico City basin. Column averaged, aerosol size distribution (ASD) measurements were made on the ground concurrently with the lidar measurements. The ASD ground measurements allowed calculation of the column averaged mass extinction efficiency (MEE) for the lidar system (1064 nm). The value of column averaged MEE was combined with spatially resolved lidar extinction coefficients to produce total aerosol mass concentration estimates with the resolution of the lidar (1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements from DOE G-1 aircraftmore » made later in the day on 7 March 2006, allowed the evaluation of the assumptions of constant ASD with height and time used for estimating the column averaged MEE. The results showed that the aerosol loading within the basin is about twice what is observed outside of the basin. The total aerosol base concentrations observed in the basin are of the order of 200 {mu}g/m{sup 3} and the base levels outside are of the order of 100 {mu}g/m{sup 3}. The local heavy traffic events can introduce aerosol levels near the ground as high as 900 {mu}g/m{sup 3}. The article presents the methodology for estimating aerosol mass concentration from mobile, ground-based lidar measurements in combination with aerosol size distribution measurements. An uncertainty analysis of the methodology is also presented.« less

  18. Dietary intake of polyphenols, nitrate and nitrite and gastric cancer risk in Mexico City

    PubMed Central

    Hernández-Ramírez, Raúl U.; Galván-Portillo, Marcia V.; Ward, Mary H.; Agudo, Antonio; González, Carlos A.; Oñate-Ocaña, Luis F.; Herrera-Goepfert, Roberto; Palma-Coca, Oswaldo; López-Carrillo, Lizbeth

    2009-01-01

    N-Nitroso compounds (NOC) are potent animal carcinogens and potential human carcinogens. The primary source of exposure for most individuals may be endogenous formation, a process that can be inhibited by dietary polyphenols. To estimate the risk of gastric cancer (GC) in relation to the individual and combined consumption of polyphenols and NOC precursors (nitrate and nitrite), a population-based case–control study was carried out in Mexico City from 2004 to 2005 including 257 histologically confirmed GC cases and 478 controls. Intake of polyphenols, nitrate and nitrite were estimated using a food frequency questionnaire. High intakes of cinnamic acids, secoisolariciresinol and coumestrol were associated with an ~50% reduction in GC risk. A high intake of total nitrite as well as nitrate and nitrite from animal sources doubled the GC risk. Odds ratios around 2-fold were observed among individuals with both low intake of cinnamic acids, secoisolariciresinol or coumestrol and high intake of animal-derived nitrate or nitrite, compared to high intake of the polyphenols and low animal nitrate or nitrite intake, respectively. Results were similar for both the intestinal and diffuse types of GC. Our results show, for the first time, a protective effect for GC because of higher intake of cinnamic acids, secoisolariciresinol and coumestrol, and suggest that these polyphenols reduce GC risk through inhibition of endogenous nitrosation. The main sources of these polyphenols were pears, mangos and beans for cinnamic acids; beans, carrots and squash for secoisolariciresinol and legumes for coumestrol. PMID:19449378

  19. Sweetened beverages intake, hyperuricemia and metabolic syndrome: the Mexico City Diabetes Study.

    PubMed

    López-Molina, Rubén; Parra-Cabrera, Socorro; López-Ridaura, Ruy; González-Villalpando, María E; Ferrannini, Ele; González-Villalpando, Clicerio

    2013-12-01

    OBJECTIVE. To determine prevalence of hyperuricemia and its relation with intake of sweetened beverages (SB) and metabolic syndrome (MS) in low income urban Mexican population. MATERIALS AND METHODS. A cross-sectional analysis of The Mexico City Diabetes Study, a prospective population-based investigation (1 173 participants) was performed. We used logistic regression, adjusted by pertinent variables. We determined prevalence of hyperuricemia and explored associations of uric acid levels with MS and intake of SB. RESULTS. Prevalence of hyperuricemia was 26.5 and 19.8% in males and females respectively. In an adjusted multivariate model, body mass index, waist circumference, and triglyceride were higher as uric acid quartiles increased (p<0.005-0.001). The odds ratio for MS was 1.48 for 3rd uric acid quartile and 2.03 for 4th quartile. Higher consumption of SB was associated with higher uric acid levels (p<0.001). CONCLUSION. Prevalence of hyperuricemia is high. Potential association with intake of SB, resulting in metabolic alterations should be considered.

  20. Propane and butane emission sources to ambient air of Mexico City metropolitan area.

    PubMed

    Jaimes, L; Sandoval, J

    2002-04-22

    Samples of volatile organic compounds (VOCs) were collected in a smog chamber in order to determine whether automotive exhausts or LP Gas emissions play a greater role in the source of propane and butane, which affect ozone formation and other pollutants in the ambient air of the Mexico City metropolitan area (MCMA). These samples were collected in April 1995 during mornings and evenings. The testing methodology used for measuring exhaust emission were FTP or EPA-74 tests, and SHED type tests were also conducted in order to evaluate evaporative emissions. The finding from analysis of the VOCs collected in the morning demonstrate that in the atmosphere, propane concentrations are higher than that of butane but the reverse in evaporative and exhaust emissions, with the concentration of propane lower than that of butane. Our conclusion is that most of C3 and C4 in the ambient air comes from LP gas and not vehicle exhaust or evaporative emission, due to the higher levels of propane than butane in its formulation. The analysis of VOCs also indicates that although the conversion (in the smog chamber) of alkanes is low during the day, due to the high initial concentration, their contribution in the reaction mechanism to produce ozone can be appreciable.

  1. Atmospheric PM2.5 Mercury in the Metropolitan Area of Mexico City.

    PubMed

    Morton-Bermea, Ofelia; Garza-Galindo, Rodrigo; Hernández-Álvarez, Elizabeth; Ordoñez-Godínez, Sara L; Amador-Muñoz, Omar; Beramendi-Orosco, Laura; Miranda, Javier; Rosas-Pérez, Irma

    2018-04-01

    In this study, atmospheric mercury concentration in airborne particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM 2.5 ) was analyzed by ICP-MS. Samples were collected in the Mexico City Metropolitan Area (MCMA), during 2013, in five locations, Northwest, Northeast (NE), Central, Southwest and Southeast, along three seasons: dry warm, rainy, and dry cold (DC). It can be observed that NE shows the highest mercury concentration (p < 0.05), where pollution events were identified. The seasonal distribution shows that samples collected during DC present the highest concentration (p < 0.05). These results are in agreement with the distribution of important mercury industrial sources located in the northern urban area as well with the temperature and wind conditions during 2013. The comparison of data obtained in this work with those of similar previous studies clearly indicates a decrease, between 2006 and 2013, of mercury content in PM 2.5 collected in MCMA.

  2. [The clinico-epidemiological characteristics of cholera patients in Mexico City].

    PubMed

    Vilchis-Guizar, A E; Uribe-Márquez, S; Pérez-Sánchez, P L

    1999-01-01

    To compare the clinical and epidemiological characteristics of cholera patients and patients with diarrhea of different etiology (controls), treated at Mexican Institute of Social Security medical units in northeast Mexico City, from 1995 to 1998. Cross-sectional analytical study design. Data were collected using the official form "Immediate Notification of Cholera Cases" that each medical unit reports to the Coordination of Community Health. Statistical analysis consisted of comparisons of means and proportions between both groups. In 4,952 notifications, there were 588 cholera cases and 4,364 controls. The age range of cases was 39 to 51 years and 54% were females. During 1995 and 1997 (years with higher proportion of cases) patients with cholera had a greater frequency of watery evacuations than controls (97% vs. 73%), "rice water" appearance (31% vs. 13%), vomiting (72% vs. 63%), muscular spasms (49% vs. 26%), dehydration (83% vs. 71%), hypovolemic shock (10% vs. 1%) and death (0.85% vs. 0.25%). These differences were statistically significant. Cholera presents a biannual cyclic behavior; greater frequencies are associated with greater severity and complications. It is necessary to increase epidemiologic surveillance and medical efforts for opportune diagnosis and treatment.

  3. Irrigation water quality in southern Mexico City based on bacterial and heavy metal analyses

    NASA Astrophysics Data System (ADS)

    Solís, C.; Sandoval, J.; Pérez-Vega, H.; Mazari-Hiriart, M.

    2006-08-01

    Xochimilco is located in southern Mexico City and represents the reminiscence of the pre-Columbian farming system, the "chinampa" agriculture. "Chinampas" are island plots surrounded by a canal network. At present the area is densely urbanized and populated, with various contaminant sources contributing to the water quality degradation. The canal system is recharged by a combination of treated-untreated wastewater, and precipitation during the rainy season. Over 40 agricultural species, including vegetables, cereals and flowers, are produced in the "chinampas". In order to characterize the quality of Xochimilcos' water used for irrigation, spatial and temporal contaminant indicators such as microorganisms and heavy metals were investigated. Bacterial indicators (fecal coliforms, fecal enterococcus) were analyzed by standard analytical procedures, and heavy metals (such as Fe, Cu, Zn and Pb) were analyzed by particle induced X-ray emission (PIXE). The more contaminated sites coincide with the heavily populated areas. Seasonal variation of contaminants was observed, with the higher bacterial counts and heavy metal concentrations reported during the rainy season.

  4. Connectivity, prison environment and mental health among first-time male inmates in Mexico City.

    PubMed

    Albertie, Ariel; Bourey, Christine; Stephenson, Rob; Bautista-Arredondo, Sergio

    2017-02-01

    Research from high-income countries suggests that prison populations are affected disproportionately by mental illness. However, little research has examined mental health among prisoners in low- and middle-income countries or associations between mental health and contextual factors surrounding the prison experience among susceptible first-time inmates in these settings. The current study examines associations between connectivity, prison environment and mental health (major depression and substance use) among novice male inmates (n = 593) in three Mexico City prisons. Severe depression (46.2%), any substance use (53.8%) and heavy substance use (45.7%) were prevalent. Among key co-variates, recent visitors were protective for severe depression, conjugal visits for any substance use and prison employment for heavy substance use. Physical attacks were associated with increased prevalence of depression, sentence time served with both any and heavy substance use and overcrowding with any substance use. These findings suggest the need for routine health assessments to improve identification and treatment programmes to minimise mental health burden. Addressing demographic risk factors as well as contextual determinants, by decreasing physical violence and overcrowding and supporting outside connections for prisoners, may help improve inmate mental health.

  5. Morbidity following Mexico City's 1985 earthquakes: clinical and epidemiologic findings from hospitals and emergency units.

    PubMed

    Sánchez-Carrillo, C I

    1989-01-01

    Medical records of 822 inpatients and outpatients cared for by the Department of the Federal District medical services during the 1985 Mexico City earthquakes were reviewed. Record incompleteness varied between 92.8 percent and 14.0 percent for the various study variables. No gender differences were detected among the groups; more than 70.0 percent of the patients were ages 15 to 64 years. Multiple traumatic injuries were frequent for inpatients across age groups, while simple contusions were more frequent among outpatients. Multiple head traumas, thorax-abdomen multiple traumas, and simple fractures of an arm or leg were more frequently recorded for inpatients than for outpatients. Head wounds with contusions; simple contusion of the thorax-abdomen, arms, and legs; and psychological trauma were more frequently recorded for outpatients. Although a great many records were incomplete, the data may reflect what actually happened to these patients, given the similarity of the findings with other reports of disasters. Improved record keeping during emergencies is needed to standardize the quantity and the reliability of the data so that statistical and medical care requirements are soundly based. The use of standard questionnaires for data collection is stressed to facilitate the management of clinical and epidemiologic activities. Longitudinal studies are needed to determine patterns of physical injuries, psychological trauma, and survival.

  6. Morbidity following Mexico City's 1985 earthquakes: clinical and epidemiologic findings from hospitals and emergency units.

    PubMed Central

    Sánchez-Carrillo, C I

    1989-01-01

    Medical records of 822 inpatients and outpatients cared for by the Department of the Federal District medical services during the 1985 Mexico City earthquakes were reviewed. Record incompleteness varied between 92.8 percent and 14.0 percent for the various study variables. No gender differences were detected among the groups; more than 70.0 percent of the patients were ages 15 to 64 years. Multiple traumatic injuries were frequent for inpatients across age groups, while simple contusions were more frequent among outpatients. Multiple head traumas, thorax-abdomen multiple traumas, and simple fractures of an arm or leg were more frequently recorded for inpatients than for outpatients. Head wounds with contusions; simple contusion of the thorax-abdomen, arms, and legs; and psychological trauma were more frequently recorded for outpatients. Although a great many records were incomplete, the data may reflect what actually happened to these patients, given the similarity of the findings with other reports of disasters. Improved record keeping during emergencies is needed to standardize the quantity and the reliability of the data so that statistical and medical care requirements are soundly based. The use of standard questionnaires for data collection is stressed to facilitate the management of clinical and epidemiologic activities. Longitudinal studies are needed to determine patterns of physical injuries, psychological trauma, and survival. PMID:2508177

  7. Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City.

    PubMed

    Palma-Martínez, Ingrid; Guerrero-Mandujano, Andrea; Ruiz-Ruiz, Manuel J; Hernández-Cortez, Cecilia; Molina-López, José; Bocanegra-García, Virgilio; Castro-Escarpulli, Graciela

    2016-01-01

    Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii , and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx 1 /stx 2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures. The capacity to express active Stx1 and Stx2 toxins was determined in Vero cell cultures and the concentration of Stx was evaluated by 50% lethal dose (LD 50 ) assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas , and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures. Furthermore, these results indicate that the Aeromonas genus might be a potential causative agent of HUS.

  8. Risk factors for high levels of lead in blood of schoolchildren in Mexico City.

    PubMed

    Olaiz, G; Fortoul, T I; Rojas, R; Doyer, M; Palazuelos, E; Tapia, C R

    1996-01-01

    Risk factors associated with blood lead levels exceeding 15 microg/dl were analyzed in this report. This relatively high lead level was selected because, at the time the study commenced, it was considered to be a "safe" level. A total of 1583 schoolchildren were studied. The students were from (a) two areas in Mexico City (Tlalnepantla and Xalostoc) that have had historically high concentrations of lead in air, and (b) three areas (Pedregal, Iztalpalapa, and Centro) with less impressive air lead levels. Parents were presented with a questionnaire that solicited information about lead risk factors. A bivariate analysis and a multilogistic analysis were conducted to identify associations and to identify the model that most accurately explains the variability of the sample. High blood lead concentrations were found in children who lived in Xalostoc and Tlalnepantla (16.1 and 17.0 microg/dl, respectively), and the lowest concentration (i.e., 10 microg/dl) was found in children from Iztapalapa. The strongest association was with area of residence, followed by education level of parents, cooking of meals in glazed pottery, and chewing or sucking of yellow or other colored pencils. A child's area of residence is the most significant risk factor that must be accounted for when any study of lead and blood lead concentrations is undertaken. Follow-up in similar populations should assist greatly in the evaluation of the impact of governmental actions on public health.

  9. Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City

    PubMed Central

    Palma-Martínez, Ingrid; Guerrero-Mandujano, Andrea; Ruiz-Ruiz, Manuel J.; Hernández-Cortez, Cecilia; Molina-López, José; Bocanegra-García, Virgilio; Castro-Escarpulli, Graciela

    2016-01-01

    Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii, and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx1/stx2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures. The capacity to express active Stx1 and Stx2 toxins was determined in Vero cell cultures and the concentration of Stx was evaluated by 50% lethal dose (LD50) assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas, and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures. Furthermore, these results indicate that the Aeromonas genus might be a potential causative agent of HUS. PMID:27725813

  10. [Working conditions in outpatient clinics adjacent to private pharmacies in Mexico City: perspective of physicians].

    PubMed

    Díaz-Portillo, Sandra P; Reyes-Morales, Hortensia; Cuadra-Hernández, Silvia Magali; Idrovo, Álvaro J; Nigenda, Gustavo; Dreser, Anahí

    To analyse the working conditions of physicians in outpatient clinics adjacent to pharmacies (CAFs) and their organizational elements from their own perspective. We carried out an exploratory qualitative study. Semi-structured interviews were conducted with 32 CAF physicians in Mexico City. A directed content analysis technique was used based on previously built and emerging codes which were related to the experience of the subjects in their work. Respondents perceive that work in CAFs does not meet professional expectations due to low pay, informality in the recruitment process and the absence of minimum labour guarantees. This prevents them from enjoying the benefits associated with formal employment, and sustains their desire to work in CAF only temporarily. They believe that economic incentives related to number of consultations, procedures and sales attained by the pharmacy allow them to increase their income without influencing their prescriptive behaviour. They express that the monitoring systems and pressure exerted on CAFs seek to affect their autonomy, pushing them to enhance the sales of medicines in the pharmacy. Physicians working in CAFs face a difficult employment situation. The managerial elements used to induce prescription and enhance pharmacy sales create a work environment that generates challenges for regulation and underlines the need to monitor the services provided at these clinics and the possible risk for users. Copyright © 2017 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Márquez, C.; Bueno, E.; Bernabé, R. M.; Sánchez, A.; Fentanes, O.; Wöhrnschimmel, H.; Cárdenas, B.; Kamilla, A.; Wakamatsu, S.; Molina, L. T.

    2007-08-01

    The evolution of ozone and 13 volatile organic compounds (VOCs) in the boundary layer of Mexico City was investigated during 2000-2004 to improve our understanding of the complex interactions between those trace gases and meteorological variables, and their influence on the air quality of a polluted megacity. A tethered balloon, fitted with electrochemical and meteorological sondes, was used to obtain detailed vertical profiles of ozone and meteorological parameters up to 1000 m above ground during part of the diurnal cycle (02:00-18:00 h). VOCs samples were collected up to 200 m by pumping air to canisters with a Teflon tube attached to the tether line. Overall, features of these profiles were found to be consistent with a simple picture of nighttime trapping of ozone in an upper residual layer and of VOCs in a shallow unstable layer above the ground. After sunrise an ozone balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with NO, delaying the ground-level ozone rise by 2 h. The subsequent evolution of the conductive boundary layer and vertical distribution of pollutants are discussed in terms of the energy balance, the presence of turbulence and the atmospheric stability.

  12. Air pollution problem in the Mexico City metropolitan zone: Photochemical pollution

    SciTech Connect

    Alvarez, H.B.; Alvarez, P.S.; Echeverria, R.S.

    1997-12-31

    Mexico City Metropolitan Zone (MCMZ) represents an example of a megacity where the air pollution problem has reached an important evolution in a very short time, causing a risk in the health of a population of more than 20 million inhabitants. The atmospheric pollution problem in the MCMZ, began several decades ago, but it increased drastically in the middle of the 80`s. It is important to recognize that in the 60`s, 70`s and the first half of the 80`s the main pollutants were sulfur dioxide and total suspended particles. However since the second half of the 80`s until now, ozonemore » is the most important air pollutant besides of the suspended particles (PM{sub 10}) and other toxic pollutants (1--8). The purpose of this paper is to discuss the evolution of the ozone atmospheric pollution problem in the MCMZ, as well as to analyze the results of several implemented air pollution control strategies.« less

  13. 'Without a plan' but 'keeping on track': views on contraception, pregnancy and abortion in Mexico City.

    PubMed

    Juarez, Fatima; Bayer, Angela M

    2011-01-01

    Despite increased use of modern contraception among Mexican women, there has been a significant increase in abortions. Little is known about the experiences behind these trends. This study examines decision-making around contraception, pregnancy, childbearing and abortion. We carried out 26 in-depth interviews with 23- to 35-year-old females and males in Mexico City. Interviewees described reproductive planning 'without a plan' and sporadic contraceptive use. Linking of reproductive preferences and contraceptive use occurred only after raising a child for a few years or after experiencing an abortion. Interviewees described side effects of hormonal contraceptives and the intrauterine device (IUD) and problems with condoms. Only 8% of participants disagreed with abortion completely. Those with mixed views opposed abortion for pregnancies resulting from lack of responsibility or due to personal problems or concerns about one's future. However, these more controversial reasons were the primary motivations for terminating pregnancies. Females and males expressed that females made most decisions related to contraception, pregnancy and abortion. Further research could explore the reasons behind reproductive planning 'without a plan', 'on and off' contraceptive use and abortion beliefs and experiences that are somewhat contradictory.

  14. [Experience and knowledge about climateric and menopause in women in Mexico City].

    PubMed

    Velasco-Murillo, V; Navarrete-Hernández, E; Ojeda-Mijares, R I; Pozos-Cavanzo, J L; Camacho-Rodríquez, M A; Cardona-Pérez, J A

    2000-01-01

    To know the experiences and knowledge about climateric and menopause in a group of women covered by Instituto Mexicano del Seguro Social (IMSS). The purpose was to contribute for planning some strategies to increase seeking for medical care at these periods of life. Descriptive survey study in a randomized sample of women aged 50-59 years, currently users of medical services in family medicine system of IMSS en Mexico City, with a confidence interval of 95%. Mean age at menopause was 47.8 years. Most frequent climateric symptoms were: hot flushes (70.9%), depression (60.2%), insomnia (53.5%) and menstrual disturbances (37.8%). 51.1% of women seeked medical care due to climateric symptoms but only 12.1% received treatment, majority hormonals (81.6%). Past users were 14.9% and they received hormones too in 87.8%. In this survey, 83.8% of women had some knowledge about main symptoms of climateric and 90.1% knew about osteoporosis but only 37.2% had some knowledge about cardiovascular risk after menopause. The prevention of osteoporosis and coronary disease was associated with calcium and exercise; only in 1% with use of hormonals. It exists an acceptable level of information about climateric syndrome and postmenopausal osteoporosis in these women, but it is low for risk of cardiovascular disease. Probably, their information is got from the mass media communication and did not for the activities of medical institutions in health education.

  15. Impacts of black carbon and co-pollutant emissions from transportation sector in Mexico City

    NASA Astrophysics Data System (ADS)

    Zavala, Miguel; Almanza, Victor; Garcia, Agustin; Jazcilevich, Aron; Lei, Wenfang; Molina, Luisa

    2016-04-01

    Black carbon is one of the most important short-lived climate-forcing agents, which is harmful to human health and also contributes significantly to climate change. Transportation is one of the largest sources of black carbon emissions in many megacities and urban complexes, with diesel vehicles leading the way. Both on-road and off-road vehicles can emit substantial amounts of harmful BC-containing particulate matter (PM) and are also responsible for large emissions of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and many other co-emitted volatile organic compounds (VOCs). Regionally, black carbon emissions contributions from mobile sources may vary widely depending on the technical characteristics of the vehicle fleet, the quality and chemical properties of the fuels consumed, and the degree of local development and economic activities that foster wider and more frequent or intensive use of vehicles. This presentation will review and assess the emissions of black carbon from the on-road and off-road transportation sector in the Mexico City Metropolitan Area. Viable mitigation strategies, including innovative technological alternatives to reduce black carbon and co-pollutants in diesel vehicles and their impacts on climate, human health and ecosystems will be described.

  16. Predicting Women’s Utilization of Primary Care Mental Health Services in Mexico City

    PubMed Central

    Mendoza, Karla; Ulloa, Arianna; Saavedra, Nayelhi; Galván, Jorge; Berenzon, Shoshana

    2016-01-01

    Objective: To analyze factors associated with and predicting Mexican women seeking primary care mental health services (PCMHS) and provide suggestions to increase PCMHS utilization. Method: We administered a questionnaire to (N = 456) female patients in Mexico City primary care clinics. We conducted chi-square analyses of seeking PCMHS and sociodemographic variables, perceptions of and experiences with PCMHS. Our results and literature review guided our logistic regression model. Results: Women referred to a mental health provider (MHP; odds ratio [OR] = 10.81, 95% CI = 3.59-32.51), whose coping mechanisms included talking to a MHP (OR = 5.53, 95% CI = 2.10-14.53), whose primary worry is loneliness (OR = 8.15, 95% CI = 1.20-55.10), and those who follow doctor’s orders; were more likely to seek PCMHS (OR = 0.28, 95% CI = 0.09-0.92). Conclusions: Primary care providers play a fundamental role in women’s decisions to seek PCMHS. Proper referrals to PCMHS should be encouraged. PMID:27856559

  17. [Distribution of aquatic birds in oxidation lagoons of La Paz city in South Baja California, Mexico].

    PubMed

    Zamora-Orozco, Elvia Margarita; Carmona, Roberto; Brabata, Georgina

    2007-06-01

    Taxonomic composition, spatial and temporal distribution of aquatic birds in oxidation lagoons (LO) of La Paz city in south Baja California, Mexico, were determined during 24 censuses realized in two-week intervals (April/98-March/99). There are five lagoons of5 Ha each and 17 ha of terrains constantly flooded that serve as feeding areas for cattle and birds. One hundred twenty three species were observed, 75 of which were aquatic birds. A total of 46 041 observations were made (average 1 918 birds/census). Richness and abundance of aquatic birds were influenced mainly by migration of anatids and sandpipers. The first group had the greatest abundance due to its affinity towards fresh water bodies. The terrains were the favorite sites of dabbling ducks (Anas) and sandpipers. In contrast, two of the most abundant species (Oxyura jamaicensis, 12.5% of all species, and Fulica americana, 8.8 %) restricted their presence to the oxidation lagoons. LO presented a bird structure of its own and atypical, according to the dryness of the region.

  18. Addiction-Related Stigma and Discrimination: A Qualitative Study in Treatment Centers in Mexico City.

    PubMed

    Mora-Ríos, Jazmín; Ortega-Ortega, Miriam; Medina-Mora, Maria Elena

    2017-04-16

    Social rejection of drug use is greater than that directed at other psychiatric conditions, like depression and anxiety, which may lead to social exclusion of substance users and prevent them from seeking and receiving treatment. The objective of this study is to investigate the stigma and discrimination related to addiction in treatment centers in Mexico City. Data are from a broad mixed methods study. The present study is a qualitative analysis of 35 in-depth interviews of drug users, family members, and providers, using guidelines for the exploration of experiences of stigma and discrimination related to substance abuse. A thematic analysis was carried out using specialized software (Atlas.ti 6.2.23). The common practices of stigma and discrimination (e.g., judging, mockery, inappropriate comments, overprotection, and hostile looks), were identified in participant testimonies. The narratives provide evidence of varied conditions of social and gender inequality, as well as experience of violence and abuse, that refer to a structural context of discrimination surrounding addiction, and that constitute obstacles to treatment. The findings allow for a description of the stigmatization process surrounding addiction as a shared problem that requires the implementation of coordinated treatment strategies. They also suggest the need for more comprehensive policies of inclusion, based on human rights, which favor prevention and treatment.

  19. Development and testing of meteorology and air dispersion models for Mexico City

    NASA Astrophysics Data System (ADS)

    Williams, M. D.; Brown, M. J.; Cruz, X.; Sosa, G.; Streit, G.

    Los Alamos National Laboratory and Instituto Mexicano del Petróleo are completing a joint study of options for improving air quality in Mexico City. We have modified a three-dimensional, prognostic, higher-order turbulence model for atmospheric circulation (HOTMAC) and a Monte Carlo dispersion and transport model (RAPTAD) to treat domains that include an urbanized area. We used the meteorological model to drive models which describe the photochemistry and air transport and dispersion. The photochemistry modeling is described in a separate paper. We tested the model against routine measurements and those of a major field program. During the field program, measurements included: (1) lidar measurements of aerosol transport and dispersion, (2) aircraft measurements of winds, turbulence, and chemical species aloft, (3) aircraft measurements of skin temperatures, and (4) Tethersonde measurements of winds and ozone. We modified the meteorological model to include provisions for time-varying synoptic-scale winds, adjustments for local wind effects, and detailed surface-coverage descriptions. We developed a new method to define mixing-layer heights based on model outputs. The meteorology and dispersion models were able to provide reasonable representations of the measurements and to define the sources of some of the major uncertainties in the model-measurement comparisons.

  20. Investigation of OxProduction Rates in the Mexico City Metropolitan Area during MILAGRO

    NASA Astrophysics Data System (ADS)

    Dusanter, S.; Molina, L. T.; Stevens, P. S.

    2009-12-01

    Understanding the oxidative capacity of the atmosphere and the formation of secondary pollutants are important issues in atmospheric chemistry. For instance, the photochemical production of tropospheric ozone (O3) is of particular interest due to its detrimental effects on both human health and agricultural ecosystems. A detailed characterization of tropospheric O3 production rates will help in the development of effective control strategies. The 2006 Mexico City Metropolitan Area field campaign (MCMA-2006) was one of four components of MILAGRO (Megacity Initiative: Local And Global Research Observations) intended to collect information on the impact of megacity emissions on local, regional and global scales. In this presentation, rates of production of Ox (Ox = O3 + NO2) species during MCMA-2006 at the supersite T0 (Instituto Mexicano del Petroleo) will be presented using different approaches based on measured and modeled concentrations of ROx (OH + HO2 + RO2) radicals. In addition, we will examine both the reactivity of OH and the contribution of specific peroxy radicals to the oxidation rate of NO to estimate the contribution of groups of VOCs (alkanes, alkenes, aromatics, oxygenated and biogenic VOCs) to the total production rate of Ox species.

  1. Assessing Pesticide Contamination to Fresh Water in Some Agricultural Sites, Close to Oaxaca City, Mexico

    NASA Astrophysics Data System (ADS)

    Tomas, G.

    2002-12-01

    This study presents the results of a survey on pesticides in fresh water in shallow aquifers, rivers and dams in Zaachila, Tlacolula and Etla and agricultural valleys close to Oaxaca City, SW of Mexico. In the study zones, there are generalized uses of pesticides and the impact on the water resources by inadequate use of agricultural activities. Water is used for irrigation and drinking. Surveying criteria was to sample the aquifer (production wells), its water table (dig wells) and a regional water collector (Plan Benito Juarez Yuayapan dam). A total of 14 samples were analyzed for the identification and quantification of organochlorine and organophosphorous pesticides. Method was 508-EPA. Gas chromatographer was a 5890 series II Hewlett Packard, calibrated with several patterns. Results: 10 samples are contaminated with some pesticide of the used patterns; Dieldrin, Chlordano, Malathion, Mirex were not found; Traces of organophosphorus compounds were found in 8 samples, mainly Merphos, Parathion Ethylic and Disulfoton ; There was detected traces of world-forbidden insecticides as Metoxychlor, Parathion Ethylic and Disulfoton; and In one sample (Cuilapam well #1) DDT exceeds, the Mexican maximum limit for potable water (1 mg/l),

  2. Hydrocarbons derived from petroleum in bottled drinking water from Mexico City.

    PubMed

    Vega, Salvador; Gutiérrez, Rey; Ortiz, Rutilio; Schettino, Beatriz; Ramírez, Maria de Lourdes; Pérez, José Jesus

    2011-06-01

    This paper describes the concentrations of polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs) derived from petroleum in bottled drinking water samples that were collected over 1 year from Mexico City in two bottle sizes (1.5 and 19 L), all brought in supermarkets. The analysis was by gas chromatography with flame ionization detection. -Concentrations of AHs (9.26-1.74 μg/L) were greater than PAHs (20.15-12.78 ng/L). Individual concentrations of PAHs such as fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were comparable with data reported by the World Health Organization (WHO). Total concentrations of PAHs for all samples (BDW1: 12.78 μg/L, BDW2: 16.72 μg/L, BDW3: 14.62 μg/L, BDW4: 20.15 μg/L and BDW5: 13.23 ng/L) were below the maximum permissible European level of 100 ng/L; no regulations exist for AHs although their values were greater than PAHs (BDW1: 3.11 μg/L, BDW2: 8.45 μg/L, BDW3: 1.74 μg/L, BDW4: 4.75 μg/L and BDW5: 9.26 μg/L).

  3. Presence of polychlorinated biphenyls (PCBs) in bottled drinking water in Mexico City.

    PubMed

    Salinas, Rutilio Ortiz; Bermudez, Beatriz Schettino; Tolentino, Rey Gutiérrez; Gonzalez, Gilberto Díaz; Vega y León, Salvador

    2010-10-01

    This paper describes the concentrations of seven polychlorinated biphenyls (PCBs) in bottled drinking water samples that were collected over 1 year from Mexico City in two sizes (1.5 and 19 L), using gas chromatography with an electron capture detector. PCBs 28 (0.018-0.042 μg/L), 52 (0.006-0.015 μg/L) and 101 (0.001-0.039 μg/L) were the most commonly found and were present in the majority of the samples. However, total concentrations of PCBs in bottled drinking water (0.035-0.039 μg/L) were below the maximum permissible level of 0.50 μg/L stated in Mexican regulations and probably do not represent a hazard to human health. PCBs were detectable in all samples and we recommend a monitoring program be established to better understand the quality of drinking bottled water over time; this may help in producing solutions for reducing the presence of organic contaminants.

  4. Years of life lost (Yll) attributable to alcohol consumption in Mexico City.

    PubMed

    Pérez-Pérez, Eduardo; Cruz-López, Leonardo; Hernández-Llanes, Norberto Francisco; Gallegos-Cari, Andrea; Camacho-Solís, Rafael Edgardo; Mendoza-Meléndez, Miguel Ángel

    2016-01-01

    The aim of this study was to estimate the YLL attributable to alcohol consumption in Mexico City from 2006 - 2012. Vital statistics on mortality attributable to alcohol consumption from the INEGI (Instituto Nacional de Estadística y Geografía) were used to determine YLL as well as the average age of death in relation to different age ranges by sex. A total estimate of 168,607 YLL was obtained, with an average loss of 18.32 years being observed for men and 17.54 years for women. Men accounted for a higher proportion of the YLL than women. According to the ICD-10 (Tenth Revision of International Classification of Diseases), liver disease attributable to alcohol consumption was found to be responsible for more than 80% of the total YLL. There was a cyclical trend in YLL from 2006 to 2012. The YLL attributable to alcohol suggest that alcohol consumption is a public health problem that involves losses in productivity and economic costs, and the decline in YLL could be explained by the decrease in income caused by the economic crisis of 2008, just as the increase could be explained by economic improvement in 2012.

  5. Air pollution, inflammation and preterm birth in Mexico City: study design and methods.

    PubMed

    O'Neill, Marie S; Osornio-Vargas, Alvaro; Buxton, Miatta A; Sánchez, Brisa N; Rojas-Bracho, Leonora; Castillo-Castrejon, Marisol; Mordhukovich, Irina B; Brown, Daniel G; Vadillo-Ortega, Felipe

    2013-03-15

    Preterm birth is one of the leading causes of perinatal mortality and is associated with long-term adverse health consequences for surviving infants. Preterm birth rates are rising worldwide, and no effective means for prevention currently exists. Air pollution exposure may be a significant cause of prematurity, but many published studies lack the individual, clinical data needed to elucidate possible biological mechanisms mediating these epidemiological associations. This paper presents the design of a prospective study now underway to evaluate those mechanisms in a cohort of pregnant women residing in Mexico City. We address how air quality may act together with other factors to induce systemic inflammation and influence the duration of pregnancy. Data collection includes: biomarkers relevant to inflammation in cervico-vaginal exudate and peripheral blood, along with full clinical information, pro-inflammatory cytokine gene polymorphisms and air pollution data to evaluate spatial and temporal variability in air pollution exposure. Samples are collected on a monthly basis and participants are followed for the duration of pregnancy. The data will be used to evaluate whether ambient air pollution is associated with preterm birth, controlling for other risk factors. We will evaluate which time windows during pregnancy are most influential in the air pollution and preterm birth association. In addition, the epidemiological study will be complemented with a parallel toxicology invitro study, in which monocytic cells will be exposed to air particle samples to evaluate the expression of biomarkers of inflammation. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Air pollution, inflammation and preterm birth in Mexico City: Study design and methods

    PubMed Central

    O’Neill, Marie S.; Osornio-Vargas, Alvaro; Buxton, Miatta A.; Sanchez, Brisa N.; Rojas-Bracho, Leonora; Castillo-Castrejon, Marisol; Mordhukovich, Irina B.; Brown, Daniel G.; Vadillo-Ortega, Felipe

    2012-01-01

    Preterm birth is one of the leading causes of perinatal mortality and is associated with long-term adverse health consequences for surviving infants. Preterm birth rates are rising worldwide, and no effective means for prevention currently exists. Air pollution exposure may be a significant cause of prematurity, but many published studies lack the individual, clinical data needed to elucidate possible biological mechanisms mediating these epidemiological associations. This paper presents the design of a prospective study now underway to evaluate those mechanisms in a cohort of pregnant women residing in Mexico City. We address how air quality may act together with other factors to induce systemic inflammation and influence the duration of pregnancy. Data collection includes: biomarkers relevant to inflammation in cervico-vaginal exudate and peripheral blood, along with full clinical information, pro-inflammatory cytokine gene polymorphisms and air pollution data to evaluate spatial and temporal variability in air pollution exposure. Samples are collected on a monthly basis and participants are followed for the duration of pregnancy. The data will be used to evaluate whether ambient air pollution is associated with preterm birth, controlling for other risk factors. We will evaluate which time windows during pregnancy are most influential in the air pollution and preterm birth association. In addition, the epidemiological study will be complemented with a parallel toxicology invitro study, in which monocytic cells will be exposed to air particle samples to evaluate the expression of biomarkers of inflammation. PMID:23177781

  7. Neospora caninum and Toxoplasma gondii antibodies in dogs from Durango City, Mexico.

    PubMed

    Dubey, J P; Alvarado-Esquivel, C; Liesenfeld, O; Herrera-Flores, R G; Ramírez-Sánchez, B E; González-Herrera, A; Martínez-García, S A; Bandini, L A; Kwok, O C H

    2007-10-01

    Toxoplasma gondii and Neospora caninum are structurally similar parasites, with many hosts in common. The prevalence of antibodies to T. gondii and N. caninum was determined in sera from dogs from Durango City, Mexico. Using a modified agglutination test, antibodies to T. gondii were found in 52 (51.5%) of the 101 dogs with titers of 1:25 in 27, 1:50 in 11, 1:100 in 5, 1:200 in 4, 1:400 in 2, 1:800 in 2, and 1:3,200 or higher in 1. Antibodies to N. caninum were determined by the indirect immunofluorescent antibody test (IFAT) and the Neospora sp. agglutination test (NAT). Two of the 101 dogs had N. caninum antibodies; these dogs did not have T. gondii antibodies, supporting the specificity of the tests used. The N. caninum antibody titers of the 2 dogs were: 1:400 by IFAT and 1:200 by NAT in 1, and 1:25 by NAT and IFAT in the other. Results indicate that these 2 structurally similar protozoans are antigenically different.

  8. Attitudes and anticipated reactions to genetic testing for cancer among patients in Mexico City.

    PubMed

    Romero-Hidalgo, Sandra; Urraca, Nora; Parra, Dionisio; Villa, Antonio R; Lisker, Rubén; Carnevale, Alessandra

    2009-08-01

    The aim of this study was to investigate the attitudes toward cancer predictive genetic testing in a group of non-high-risk women and men and to analyze the factors that may influence their intention to use these tests. We studied a sample of 859 outpatient women and men attending the four tertiary care hospitals of the ISSSTE (Institute of Social Security and Services for Government Employees) in Mexico City. Subjects between the ages of 30 and 74 years with no present or past history of cancer were asked to answer a questionnaire through face-to-face interview. Two different questionnaires were designed, one for women and the other for men, regarding genetic testing of a high-risk gene for breast and prostate cancer, respectively. Descriptive statistics and univariate comparisons were carried out using chi-square test, Wilcoxon's signed rank test, and Friedman test. Multivariate analysis was performed using logistic regression technique. Results showed that the majority of women attended clinics for regular check-ups and for performing screening tests to detect breast cancer, and men did not follow this pattern regarding prostate cancer. Women were more motivated to get genetic testing, more aware about its benefits, and more concerned about having cancer than men.

  9. Patient characteristics and service trends following abortion legalization in Mexico City, 2007-10.

    PubMed

    Mondragón y Kalb, Manuel; Ahued Ortega, Armando; Morales Velazquez, Jorge; Díaz Olavarrieta, Claudia; Valencia Rodríguez, Jorge; Becker, Davida; García, Sandra G

    2011-09-01

    Legal abortion services have been available in public and private health facilities in Mexico City since April 2007 for pregnancies of up to 12 weeks gestation. As of January 2011, more than 50,000 procedures have been performed by Ministry of Health hospitals and clinics. We researched trends in service users' characteristics, types of procedures performed, post-procedure complications, repeat abortions, and postabortion uptake of contraception in 15 designated hospitals from April 2007 to March 2010. The trend in procedures has been toward more medication and manual vacuum aspiration abortions and fewer done through dilation and curettage. Percentages of post-procedure complications and repeat abortions remain low (2.3 and 0.9 percent, respectively). Uptake of postabortion contraception has increased over time; 85 percent of women selected a method in 2009-10, compared with 73 percent in 2007-08. Our findings indicate that the Ministry of Health's program provides safe services that contribute to the prevention of repeat unintended pregnancies.

  10. Groundwater vulnerability assessment for organic compounds: fuzzy multi-criteria approach for Mexico city.

    PubMed

    Mazari-Hiriart, Marisa; Cruz-Bello, Gustavo; Bojórquez-Tapia, Luis A; Juárez-Marusich, Lourdes; Alcantar-López, Georgina; Marín, Luis E; Soto-Galera, Ernesto

    2006-03-01

    This study was based on a groundwater vulnerability assessment approach implemented for the Mexico City Metropolitan Area (MCMA). The approach is based on a fuzzy multi-criteria procedure integrated in a geographic information system. The approach combined the potential contaminant sources with the permeability of geological materials. Initially, contaminant sources were ranked by experts through the Analytic Hierarchy Process. An aggregated contaminant sources map layer was obtained through the simple additive weighting method, using a scalar multiplication of criteria weights and binary maps showing the location of each source. A permeability map layer was obtained through the reclassification of a geology map using the respective hydraulic conductivity values, followed by a linear normalization of these values against a compatible scale. A fuzzy logic procedure was then applied to transform and combine the two map layers, resulting in a groundwater vulnerability map layer of five classes: very low, low, moderate, high, and very high. Results provided a more coherent assessment of the policy-making priorities considered when discussing the vulnerability of groundwater to organic compounds. The very high and high vulnerability areas covered a relatively small area (71 km(2) or 1.5% of the total study area), allowing the identification of the more critical locations. The advantage of a fuzzy logic procedure is that it enables the best possible use to be made of the information available regarding groundwater vulnerability in the MCMA.

  11. An evaluation of the LPG vehicles program in the metropolitan area of Mexico City.

    PubMed

    Schifter, I; Díaz, L; López-Salinas, E; Rodríguez, R; Avalos, S; Guerrero, V

    2000-02-01

    The environmental agency in the metropolitan area of Mexico City has launched a program to introduce more energy-efficient modes of transport, one of which is the use of alternative and less polluting fuels. With the perspective in mind, a liquefied petroleum gas (LPG) fleet of vehicles is exempt of the mandatory "one day without a car" program if the emission of pollutants is below the standard authorized for that specific purpose. Today, about 28,000 light-duty vehicles and heavy-duty trucks circulate in the area, most of them as aftermarket converted vehicles. In this work, we evaluated regulated exhaust emission and other parameters on 134 representative vehicles of that fleet. From the data obtained, an estimate of emission factors and their contribution to the global emission in the metropolitan area is provided. It is concluded that more than 95% of the in-use vehicles using LPG presented regulated emissions which exceeded in one or more the environmental regulations values required for certification. The poor maintenance of the vehicles and the type of conversion kit installed could be the culprits of the results obtained.

  12. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    NASA Astrophysics Data System (ADS)

    Adachi, K.; Buseck, P. R.

    2008-05-01

    Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

  13. Impact air quality by wildfire and agricultural fire in Mexico city 2015

    NASA Astrophysics Data System (ADS)

    Mendoza Campos, Alejandra; Agustín García Reynoso, José; Castro Romero, Telma Gloria; Carbajal Pérez, José Noel; Mar Morales, Bertha Eugenia; Gerardo Ruiz Suárez, Luis

    2016-04-01

    A forest fire is a large-scale process natural combustion where different types of flora and fauna of different sizes and ages are consumed. Consequently, forest fires are a potential source of large amounts of air pollutants that must be considered when trying to relate emissions to the air quality in neighboring cities of forest areas as in the Valley of Mexico. The size, intensity and occurrence of a forest fire directly dependent variables such as weather conditions, topography, vegetation type and its moisture content and the mass of fuel per hectare. An agricultural fire is a controlled combustion, which occurred a negligence can get out of control and increase the burned area or the possibly become a wildfire. Once a fire starts, the dry combustible material is consumed first. If the energy release is large and of sufficient duration, drying green material occurs live, with subsequent burning it. Under proper fuel and environmental conditions, this process can start a chain reaction. These events occur mainly in the dry season. Forest fires and agriculture fires contribute directly in the increase of carbon dioxide (CO2) into the atmosphere; The main pollutants emitted to the atmosphere by a wildfire are the PM10, PM2.5, NOx and VOC's, the consequences have by fire are deforestation, soil erosion or change of structure and composition of forests (Villers, 2006), also it affects ecosystems and the health of the population. In this study the impact of air quality for the emissions of particulate matter less than ten microns PM10, by wildfire and agricultural fire occurred on the same day and same place, the study was evaluated in Mexico City the Delegation Milpa Alta in the community of San Lorenzo Tlacoyucan, the fire occurred on 3rd March, 2015, the wildfire duration 12 hours consuming 32 hectares of oak forest and the agricultural fire duration 6 hours consumed 16 hectares of corn. To evaluate the impact of air quality the WRF-Chem, WRF-Fire and METv3

  14. Barriers to Integrating Mental Health Services in Community-Based Primary Care Settings in Mexico City: A Qualitative Analysis.

    PubMed

    Martinez, William; Galván, Jorge; Saavedra, Nayelhi; Berenzon, Shoshana

    2017-05-01

    Despite the high prevalence of mental disorders in Mexico, minimal mental health services are available and there are large gaps in mental health treatment. Community-based primary care settings are often the first contact between patients and the health system and thus could serve as important settings for assessing and treating mental disorders. However, no formal assessment has been undertaken regarding the feasibility of implementing these services in Mexico. Before tools are developed to undertake such an assessment, a more nuanced understanding of the microprocesses affecting mental health service delivery must be acquired. A qualitative study used semistructured interviews to gather information from 25 staff in 19 community-based primary care clinics in Mexico City. Semistructured interviews were analyzed by using the meaning categorization method. In a second phase of coding, emerging themes were compared with an established typology of barriers to health care access. Primary care staff reported a number of significant barriers to implementing mental health services in primary care clinics, an already fragile and underfunded system. Barriers included the following broad thematic categories: service issues, language and cultural issues, care recipient characteristics, and issues with lack of knowledge. Results indicate that the implementation of mental health services in primary care clinics in Mexico will be difficult. However, the information in this study can help inform the integration of mental health into community-based primary care in Mexico through the development of adequate evaluative tools to assess the feasibility and progress of integrating these services.

  15. A Tale of Two Cities: San Diego (USA) and Tijuana (Mexico) El Niño Readiness

    NASA Astrophysics Data System (ADS)

    Stewart, C.; Kinoshita, A. M.; Nishikawa, T.; Briones-Gamboa, F.

    2016-12-01

    This research seeks to define the characteristics of an El Niño Ready City (ENRC) by comparing two neighboring cities, San Diego, United States and Tijuana, Mexico, with diverse management and social conditions, yet similar climatology. Notable El Niño years, 1982-83 and 1997-98, brought heavy precipitation and consequently significant flooding in southern California and northwest Mexico. Using the 2015-16 El Niño, we were able to investigate both Cities' historical and current preparation for hazardous events and identify lessons learned from previous events. Preparation activities include steps taken to prepare storm-related infrastructure, develop emergency protocols, establish communication and coordination efforts, and encourage public outreach and awareness. Literature, media searches, and interviews with local and regional agencies such as the San Diego Department of Transportation and Storm Water, San Diego Lifeguard Services and River Rescue Team, Tijuana State Civil Protection, and Mexican Meteorological Service Departments provided insight into the current and ongoing management for these urban Cities during the 2015-2016 El Niño. Both San Diego and Tijuana were cognizant of the 2015-2016 El Niño and anticipated above-average precipitation and had public agencies that were concerned with potential El Niño related impacts. Common challenges of inter-agency communication and coordination were noted for both Cities. By tracking the electronic media in Tijuana, we observed that local institutions respond proactively, but in a specific period of time. While, in the case of San Diego, the media analysis indicated a focus on El Niño related weather and its implications for the City as evidenced by the total number of articles related to weather across four decades. A challenge for both Cities will be to develop readiness capacities for long-term periods even if El Niño signals are weak or not present.

  16. Ozone concentrations at a selected high-elevation forest site downwind Mexico City

    NASA Astrophysics Data System (ADS)

    Torres-JArdon, R.

    2013-05-01

    Torres-Jardón, R.*, Rosas-Pérez, I., Granada-Macías, L. M., Ruiz-Suárez, L. G. Centro de Ciencias de la Atmósfera, UNAM, México D. F. México * rtorres@unam.mx For many years, the vegetation of forest species such as Abies religiosa in natural parks located in the southwest mountains of Mexico City has attracted much attention since these parks have been experiencing a severe decline of unclear etiology. The high ozone levels in the area and the observed naked eye macroscopic, histological and cytological injuries on these species, strongly suggest an important contribution of tropospheric ozone to this deterioration process. Apart of historical short monitoring campaigns for measuring ozone levels in these mountains, it is known just a little is known about the present exposure levels at which the local vegetation is exposed. A continuous ozone analyzer has been in operation since 2011 at a high-elevation forest site (Parque Nacional Miguel Hidalgo, PNMH; 3110 m above mean sea level) located downwind of Mexico City Metropolitan Area (MCMA), in order to characterize the local ozone diel amplitude and its seasonal trend, as well as the influence of MCMA on the local O3 concentrations. Hourly average ozone data in PNMH shows that in general, the diel of ozone concentrations in the forest site has a statistical significant correlation with the pattern of ozone levels observed in several monitoring sites (smog receptor sites) within the MCMA, although the high elevation O3 levels are relatively lower than those in the urban area (around 2200 m above mean sea level). It is possible that a part of the oxidants in the air masses are removed by sink deposition processes during the air mass transport across the hills. The diel amplitude of ozone concentrations is small in the cold season, increasing as the seasons advance to June. As in the city, the highest ozone concentrations occur in April or May and the lowest levels during the rainy season, which extends from

  17. Multiple scattering of waves in random media: Application to the study of the city-site effect in Mexico City area.

    NASA Astrophysics Data System (ADS)

    Ishizawa, O. A.; Clouteau, D.

    2007-12-01

    Long-duration, amplifications and spatial response's variability of the seismic records registered in Mexico City during the September 1985 earthquake cannot only be explained by the soil velocity model. We will try to explain these phenomena by studying the extent of the effect of buildings' diffracted wave fields during an earthquake. The main question is whether the presence of a large number of buildings can significantly modify the seismic wave field. We are interested in the interaction between the incident wave field propagating in a stratified half- space and a large number of structures at the free surface, i.e., the coupled city-site effect. We study and characterize the seismic wave propagation regimes in a city using the theory of wave propagation in random media. In the coupled city-site system, the buildings are modeled as resonant scatterers uniformly distributed at the surface of a deterministic, horizontally layered elastic half-space representing the soil. Based on the mean-field and the field correlation equations, we build a theoretical model which takes into account the multiple scattering of seismic waves and allows us to describe the coupled city-site system behavior in a simple and rapid way. The results obtained for the configurationally averaged field quantities are validated by means of 3D results for the seismic response of a deterministic model. The numerical simulations of this model are computed with MISS3D code based on classical Soil-Structure Interaction techniques and on a variational coupling between Boundary Integral Equations for a layered soil and a modal Finite Element approach for the buildings. This work proposes a detailed numerical and a theoretical analysis of the city-site interaction (CSI) in Mexico City area. The principal parameters in the study of the CSI are the buildings resonant frequency distribution, the soil characteristics of the site, the urban density and position of the buildings in the city, as well as

  18. Barriers and missed opportunities to HIV testing among injection drug users in two Mexico--US border cities.

    PubMed

    Moyer, Laura B; Brouwer, Kimberley C; Brodine, Stephanie K; Ramos, Rebeca; Lozada, Remedios; Cruz, Michelle Firestone; Magis-Rodriguez, Carlos; Strathdee, Steffanie A

    2008-01-01

    Despite increasing HIV prevalence in cities along the Mexico--US border, HIV testing among high-risk populations remains low. We sought to identify barriers associated with HIV testing among injection drug users (IDUs) in Tijuana and Ciudad Juarez, the two largest Mexican border cities located across from San Diego, California and El Paso, Texas, respectively. In 2005, 222 IDUs in Tijuana and 205 IDUs in Ciudad Juarez were recruited by respondent-driven sampling and administered a questionnaire to collect socio-demographic, behavioural and HIV testing history data. Blood samples were provided for serological testing of HIV, hepatitis C virus (HCV) and syphilis. Only 38% and 30% of respondents in Tijuana and Ciudad Juarez, respectively, had ever had an HIV test. The factors independently associated with never having been tested for HIV differed between the two sites, except for lack of knowledge on HIV transmission, which was independently associated in both locales. Importantly, 65% of those who had never been tested for HIV in both cities experienced at least one missed opportunity for voluntary testing, including medical visits, drug treatment and spending time in jail. Among this high-risk IDU population we found HIV testing to be low, with voluntary testing in public and private settings utilised inadequately. These findings underscore the need to expand voluntary HIV education and testing and to integrate it into services and locales frequented by IDUs in these Mexico--US border cities.

  19. [Seroreactivity to hepatitis B virus surface antigen among different population groups in the City of Durango, Mexico].

    PubMed

    Alvarado-Esquivel, Cosme; Sifuentes-Alvarez, Antonio; Pérez-Ochoa, José Francisco; García-Corral, Nora; Rodríguez-Briones, Alfredo; González-Castañeda, José Luis; Alonso-Muñoz, Citlaly María Teresa; Bracho-Huemoeller, Antonio

    2008-01-01

    To determine the seroprevalence of hepatitis B surface antigen (HBsAg) in several groups of populations in Durango City, Mexico. An observational and comparative study was conducted in 6 groups of population in a total of 775 persons in Durango City, Mexico. The groups studied were 141 registered female sex workers, 100 medical students, 150 blood donors, 104 persons applying for medical certificates, 100 pregnant women, and 180 drug addicts. Serum samples of participants were analyzed for HBsAg by an immunoassay. HBsAg confirmation was performed by neutralization assay. Out of the 775 participants, 13 (1.7%) were positive by the immunoassay, and only 1 (0.1%) resulted positive by the confirmatory assay. This positive case was a drug addict and had a history of surgery and national and international trips. The seroprevalence of HBsAg in several groups of population in Durango City is low; the seroprevalence is comparable to or lower than those informed in other Mexican cities. It is strongly recommended to perform the HBsAg confirmation test due to low specificity of the immunoassay.

  20. View From a Megacity: Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City.

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.

    2006-12-01

    As part of the Megacity Impacts on Regional and Global Environments, MIRAGE-Mex deployment to Mexico City in the period of 30 days, March 2006, a suite of photoacoustic spectrometers (PAS) were installed to measure at ground level the light absorption and scattering by aerosols at four sites: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP), a suburban site at the Technological University of Tecamac, a rural site at "La Biznaga" ranch, and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 40 and 250 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed. Comparisons with TSI nephelometer scattering and Aetholemeter absorption measurements at the T0 site will be presented. We will present a broad overview of the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site. Insight on the dynamical connections will be discussed.

  1. 78 FR 15341 - Auto Supply Chain Trade Mission to Mexico City and Monterrey, Mexico; September 23-26, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-11

    .... In 2012, Mexico produced more than 2.8 million cars- and the projection for 2013 is 3 million cars... car manufacturing, including smaller car sizes and increased fuel efficiency. The aftermarket is... opportunities include: Spare and replacement parts for gasoline and diesel engines; electrical parts, collision...

  2. Trinational Library Forum Proceedings = Memorias [del] Foro Trinacional de Bibliotecas (5th, Mexico City, Mexico, February 23-25, 1995).

    ERIC Educational Resources Information Center

    Instituto Tecnologico de Monterrey (Mexico).

    At the fifth Trinational Library Forum in 1995, 165 librarians from the United States, Canada, and Mexico gathered to discuss topics of international librarianship and exchanges, copyright regulations, and professional accreditation in information science. Presentations, with the full text in both English and Spanish, include: (1)…

  3. The Urban Tree as a Tool to Mitigate the Urban Heat Island in Mexico City: A Simple Phenomenological Model.

    PubMed

    Ballinas, Mónica; Barradas, Víctor L

    2016-01-01

    The urban heat island (UHI) is mainly a nocturnal phenomenon, but it also appears during the day in Mexico City. The UHI may affect human thermal comfort, which can influence human productivity and morbidity in the spring/summer period. A simple phenomenological model based on the energy balance was developed to generate theoretical support of UHI mitigation in Mexico City focused on the latent heat flux change by increasing tree coverage to reduce sensible heat flux and air temperature. Half-hourly data of the urban energy balance components were generated in a typical residential/commercial neighborhood of Mexico City and then parameterized using easily measured variables (air temperature, humidity, pressure, and visibility). Canopy conductance was estimated every hour in four tree species, and transpiration was estimated using sap flow technique and parameterized by the envelope function method. Averaged values of net radiation, energy storage, and sensible and latent heat flux were around 449, 224, 153, and 72 W m, respectively. Daily tree transpiration ranged from 3.64 to 4.35 Ld. To reduce air temperature by 1°C in the studied area, 63 large would be required per hectare, whereas to reduce the air temperature by 2°C only 24 large trees would be required. This study suggests increasing tree canopy cover in the city cannot mitigate UHI adequately but requires choosing the most appropriate tree species to solve this problem. It is imperative to include these types of studies in tree selection and urban development planning to adequately mitigate UHI. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Prevalent HLA Class II Alleles in Mexico City Appear to Confer Resistance to the Development of Amebic Liver Abscess.

    PubMed

    Hernández, Eric G; Granados, Julio; Partida-Rodríguez, Oswaldo; Valenzuela, Olivia; Rascón, Edgar; Magaña, Ulises; Escamilla-Tilch, Mónica; López-Reyes, Alberto; Nieves-Ramírez, Miriam; González, Enrique; Morán, Patricia; Rojas, Liliana; Valadez, Alicia; Luna, Alexandra; Estrada, Francisco J; Maldonado, Carmen; Ximénez, Cecilia

    2015-01-01

    Amebiasis is an endemic disease and a public health problem throughout Mexico, although the incidence rates of amebic liver abscess (ALA) vary among the geographic regions of the country. Notably, incidence rates are high in the northwestern states (especially Sonora with a rate of 12.57/100,000 inhabitants) compared with the central region (Mexico City with a rate of 0.69/100,000 inhabitants). These data may be related to host genetic factors that are partially responsible for resistance or susceptibility. Therefore, we studied the association of the HLA-DRB1 and HLA-DQB1 alleles with resistance or susceptibility to ALA in two Mexican populations, one each from Mexico City and Sonora. Ninety ALA patients were clinically diagnosed by serology and sonography. Genomic DNA was extracted from peripheral blood mononuclear cells. To establish the genetic identity of both populations, 15 short tandem repeats (STRs) were analyzed with multiplexed PCR, and the allelic frequencies of HLA were studied by PCR-SSO using LUMINEX technology. The allele frequencies obtained were compared to an ethnically matched healthy control group (146 individuals). We observed that both affected populations differed genetically from the control group. We also found interesting trends in the population from Mexico City. HLA-DQB1*02 allele frequencies were higher in ALA patients compared to the control group (0.127 vs 0.047; p= 0.01; pc= NS; OR= 2.9, 95% CI= 1.09-8.3). The less frequent alleles in ALA patients were HLA-DRB1*08 (0.118 vs 0.238 in controls; p= 0.01; pc= NS; OR= 0.42, 95% CI= 0.19-0.87) and HLA-DQB1*04 (0.109 vs 0.214; p= 0.02; pc= NS; OR= 0.40, 95% CI= 0.20-0.94). The haplotype HLA-DRB1*08/-DQB1*04 also demonstrated a protective trend against the development of this disease (0.081 vs. 0.178; p=0.02; pc=NS; OR= 0.40, 95% CI= 0.16-0.93). These trends suggest that the prevalent alleles in the population of Mexico City may be associated with protection against the development of ALA.

  5. Prevalent HLA Class II Alleles in Mexico City Appear to Confer Resistance to the Development of Amebic Liver Abscess

    PubMed Central

    Hernández, Eric G.; Granados, Julio; Partida-Rodríguez, Oswaldo; Valenzuela, Olivia; Rascón, Edgar; Magaña, Ulises; Escamilla-Tilch, Mónica; López-Reyes, Alberto; Nieves-Ramírez, Miriam; González, Enrique; Morán, Patricia; Rojas, Liliana; Valadez, Alicia; Luna, Alexandra; Estrada, Francisco J.; Maldonado, Carmen; Ximénez, Cecilia

    2015-01-01

    Amebiasis is an endemic disease and a public health problem throughout Mexico, although the incidence rates of amebic liver abscess (ALA) vary among the geographic regions of the country. Notably, incidence rates are high in the northwestern states (especially Sonora with a rate of 12.57/100,000 inhabitants) compared with the central region (Mexico City with a rate of 0.69/100,000 inhabitants). These data may be related to host genetic factors that are partially responsible for resistance or susceptibility. Therefore, we studied the association of the HLA-DRB1 and HLA-DQB1 alleles with resistance or susceptibility to ALA in two Mexican populations, one each from Mexico City and Sonora. Ninety ALA patients were clinically diagnosed by serology and sonography. Genomic DNA was extracted from peripheral blood mononuclear cells. To establish the genetic identity of both populations, 15 short tandem repeats (STRs) were analyzed with multiplexed PCR, and the allelic frequencies of HLA were studied by PCR-SSO using LUMINEX technology. The allele frequencies obtained were compared to an ethnically matched healthy control group (146 individuals). We observed that both affected populations differed genetically from the control group. We also found interesting trends in the population from Mexico City. HLA-DQB1*02 allele frequencies were higher in ALA patients compared to the control group (0.127 vs 0.047; p= 0.01; pc= NS; OR= 2.9, 95% CI= 1.09-8.3). The less frequent alleles in ALA patients were HLA-DRB1*08 (0.118 vs 0.238 in controls; p= 0.01; pc= NS; OR= 0.42, 95% CI= 0.19-0.87) and HLA-DQB1*04 (0.109 vs 0.214; p= 0.02; pc= NS; OR= 0.40, 95% CI= 0.20-0.94). The haplotype HLA-DRB1*08/-DQB1*04 also demonstrated a protective trend against the development of this disease (0.081 vs. 0.178; p=0.02; pc=NS; OR= 0.40, 95% CI= 0.16-0.93). These trends suggest that the prevalent alleles in the population of Mexico City may be associated with protection against the development of ALA

  6. Syringe possession arrests are associated with receptive syringe sharing in two Mexico-US border cities

    PubMed Central

    Pollini, Robin A.; Brouwer, Kimberly C.; Lozada, Remedios M.; Ramos, Rebeca; Cruz, Michelle F.; Magis-Rodriguez, Carlos; Case, Patricia; Burris, Scott; Pu, Minya; Frost, Simon D. W.; Palinkas, Lawrence A.; Miller, Cari; Strathdee, Steffanie A.

    2008-01-01

    Aims To identify factors associated with receptive syringe sharing among injection drug users (IDUs) and elucidate the association between syringe possession arrests and syringe sharing. Design Cross-sectional study. Setting Mexican border cities of Tijuana, Baja California and Ciudad Juarez, Chihuahua. Participants IDUs in Tijuana (n = 222) and Ciudad Juarez (n = 206) were recruited using respondent-driven sampling (RDS). IDUs were ≥18 years and had injected illicit drugs in the past month. Measurements An interviewer-administered survey was used to collect quantitative data on socio-demographic, behavioral and contextual characteristics, including self-reported syringe sharing and arrests for syringe possession. Associations with receptive syringe sharing were investigated using logistic regression with RDS adjustment. Findings Overall, 48% of participants reported ever being arrested for carrying an unused/sterile syringe, even though syringe purchase and possession is legal in Mexico. Arrest for possessing unused/sterile syringes was associated independently with receptive syringe sharing [adjusted odds ratio (AOR) = 2.05; 95% confidence interval (CI): 1.26, 3.35], as was injecting in a shooting gallery (AOR = 3.60; 95% CI: 2.21, 5.87), injecting in the street (AOR = 2.05; 95% CI: 1.18, 3.54) and injecting methamphetamine (AOR = 2.77; 95% CI: 1.41, 5.47) or cocaine (AOR = 1.96; 95% CI: 1.15, 3.36). More than half of participants (57%) had been arrested for possessing a used syringe; in a second model, arrest for used syringe possession was also associated independently with receptive sharing (AOR = 2.87; 95% CI: 1.76, 4.69). Conclusions We documented high levels of syringe-related arrests in two Mexican–US border cities and an independent association between these arrests and risky injection practices. Public health collaborations with law enforcement to modify the risk environment in which drug use occurs are essential to facilitate safer injection

  7. Comparing risk environments for HIV among people who inject drugs from three cities in Northern Mexico.

    PubMed

    Ospina-Escobar, Angelica; Magis-Rodríguez, Carlos; Juárez, Fatima; Werb, Dan; Bautista Arredondo, Sergio; Carreón, Rubén; Ramos, María Elena; Strathdee, Steffanie

    2018-05-18

    (AOR = 2.15, 95% CI 1.59-2.91) were significantly associated with syringe sharing (p < 0.05). Differences in HIV prevalence across cities reflect mainly differences in risk environments experienced by PWID, shaped by police practices, access to injection equipment, and dynamics of drug markets. Findings highlight the importance of ensuring sterile syringe availability through harm reduction services and a human rights approach to drug harms in northern Mexico and to generate better understanding of local dynamics and contexts of drug use for designing proper harm reduction programs.

  8. Basic statistics of PM2.5 and PM10 in the atmosphere of Mexico City.

    PubMed

    Vega, E; Reyes, E; Sánchez, G; Ortiz, E; Ruiz, M; Chow, J; Watson, J; Edgerton, S

    2002-03-27

    The high levels of fine particulate matter in Mexico City are of concern since they may induce severe public health effects as well as the attenuation of visible light. Sequential filter samplers were used at six different sites from 23 February to 22 March 1997. The sampling campaign was carried out as part of the project 'Investigación sobre Materia Particulada y Deterioro Atmosferico-Aerosol and Visibility Evaluation Research'. This research was a cooperative project sponsored by PEMEX and by the US Department of Energy. Sampling sites represent the different land uses along the city, the northwest station, Tlalnepantla, is located in a mixed medium income residential and industrial area. The northeast station, Xalostoc, is located in a highly industrialized area, Netzahualcoyotl is located in a mixed land use area, mainly commercial and residential. Station La Merced is located in the commercial and administrative district downtown. The southwest station is located in the Pedregal de San Angel, in a high-income neighborhood, and the southeast station located in Cerro de la Estrella is a mixed medium income residential and commercial area. Samples were collected four times a day in Cerro de la Estrella (CES), La Merced (MER) and Xalostoc (XAL) with sampling periods of 6 h. In Pedregal (PED), Tlalnepantla (TLA) and Netzahualcoyot1 (NEZ) sampling periods were every 24 h. In this paper the basic statistics of PM2.5 and PM10 mass concentrations are presented. The average results showed that 49, 61, 46, 57, 51 and 44% of the PM10 consisted of PM2.5 for CES, MER, XAL, PED, TLA and NEZ, respectively. The 24-h average highest concentrations of PM25 and PM10 were registered at NEZ (184 and 267 microg/m3) and the lowest at PED (22 and 39 microg/m3). The highest PM10 correlations were between XAL-CES (0.79), PED-TLA (0.80). In contrast, the highest PM2.5 correlations were between CES-PED (0.74), MER-CES (0.73) and TLA-PED (0.72), showing a lower correlation than the PM10

  9. [Knowledge and acceptance of vaccine against human papillomavirus among mothers of students from Durango city, Mexico].

    PubMed

    Sánchez Anguiano, Luis Francisco; Lechuga Quiñones, Angélica María; Milla Villeda, Reinaldo Humberto; Lares Bayona, Edgar Felipe

    2013-02-01

    Human papillomavirus (HPV) causes one of the most common sexually transmitted infections. The causal relationship between HPV and cervical cancer is one of the most important advances in the field of the prevention of this disease. The Food and Drug Administration recently approved two vaccines to prevent HPV infection. To assess the degree of knowledge about HPV and the acceptance of the vaccine against these viruses in mothers of 9 to 15 years old female students from the city of Durango, Mexico. A prospective, observational, cross-sectional and descriptive study of 470 mothers. The selection was made through random sampling stratified by age and socio-economic status of students from public and private schools in the city of Durango. We applied a questionnaire of 60 questions, 12 open and 48 closed. Groups of acceptance of the vaccine were compared by Student's t and chi2, depending on the type of variable. Reasons for prevalence of non-acceptance and its 95% of risk confidence interval were estimated. The 94% of the women surveyed knew about the vaccine. The 89% would accept vaccination of their daughters if it was free of charge, but only 40% would be willing to buy it; 88% considered that was important to their daughters to receive extensive information about the vaccine from nine years of age. The risk factors identified in this study to not allow vaccination were: not knowing the existence of the vaccine, which increased this risk 3.5 times; not having comprehensive information of the sexually transmitted diseases, which increased it by 2.49 times; and the fear to initiate their sexual life at younger age, which raised it 4.58 times. No difference was found in acceptance to the vaccine for religious or socio-economic reasons; 9% of mothers did not accept the vaccine despite of knowing its existence and the role of HPV in the genesis of cervical cancer. The vast majority of surveyed mothers accepted vaccination. The degree of knowledge about the vaccine is

  10. Evaluation of a Three-Dimensional Chemical Transport Model (PMCAMx) in the Mexico City Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Tsimpidi, A. P.; Karydis, V. A.; Zavala, M.; Lei, W.; Molina, L. T.; Pandis, S. N.

    2007-05-01

    Atmospheric aerosols have adverse effects on human health, contribute to the visibility reduction and influence the energy balance of the planet. A three-dimensional chemical transport model (PMCAMx) (Gaydos et al., 2007) is used to simulate the particular matter (PM) mass composition distribution in the Mexico City Metropolitan Area (MCMA). PMCAMx uses the framework of CAMx (ENVIRON, 2002) modelling the processes of horizontal and vertical advection, horizontal and vertical dispersion, wet and dry deposition, and gas-phase chemistry. In addition to the above, PMCAMx includes three detailed aerosol modules: inorganic aerosol growth (Gaydos et al., 2003; Koo et al., 2003a), aqueous-phase chemistry (Fahey and Pandis, 2001), and secondary organic aerosol formation and growth (Koo et al., 2004). The aerosol thermodynamic model ISORROPIA has been improved as it now simulates explicitly the chemistry of Ca, Mg, and K salts and is linked to PMCAMx. The hybrid approach (Koo et al., 2003b) for modelling aerosol dynamics is applied in order to accurately simulate the inorganic components in coarse mode. This approach assumes that the smallest particles are in equilibrium while the condensation/evaporation equation is solved for the larger ones. The new CMU organic aerosol model, which is based on the splitting of the organic aerosol volatility range in discrete bins, is also used. The model predictions are evaluated against the PM and vapour concentration measurements from the MCMA-2003 Campaign (Molina et al., 2007). References Gaydos, T., Pinder, R., Koo, B., Fahey, Κ., Yarwood, G., and Pandis, S. N., (2007). Development and application of a three-dimensional Chemical Transport Model, PMCAMx. Atmospheric Environment, in press. ENVIRON (2002). User's guide to the comprehensive air quality model with extensions (CAMx). Version 3.10. Report prepared by ENVIRON International corporation, Novato, CA Gaydos, T., Koo, B., and Pandis, S. N., (2003). Development and application of

  11. Analysis of Wedge-like Response in Mexico City during the September 19th, 2017 Puebla-Morelos Earthquake

    NASA Astrophysics Data System (ADS)

    Baena-Rivera, M.; Sanchez-Sesma, F. J.; Ramirez-Guzman, L.

    2017-12-01

    The September 19th, 2017 Puebla-Morelos earthquake (Mw7.1) caused severe structural and nonstructural damage in Mexico City in the Transition and border of the Lake geotechnical zones. Previously recorded ground motion had not reached similar high intensities. The Transition zone surrounds the base of mountain ranges and is composed of alluvial sands and silts, limited by layers of hard soil of the Hill Zone and highly compressible clay deposits of the Lake Zone. These transition configurations are modeled as dipping layers where the soft sediments progressively thicken away from the edge.We present a preliminary analysis of 2D SH and P-SV dipping layer models with homogeneous and lateral variations that resemble the known structure of the basin. Our results show the emergence of surface waves in the edges, and the spread of the energy, broadening the frequency range as compared to 1D models. The latter is a plausible explanation of the frequency content in the recorded ground motion in sites of observed damage. Acknowledgments: Records used in this research are obtained, processed and maintained by the Seismic Instrumentation Unit of the Institute of Engineering at the National Autonomous University of Mexico. This Project was funded by the Secretaría de Ciencia, Tecnología e Innovación (SECITI) of Mexico City. Project SECITI/073/2016.

  12. The contribution of evaporative emissions from gasoline vehicles to the volatile organic compound inventory in Mexico City.

    PubMed

    Schifter, I; Díaz, L; Rodríguez, R; González-Macías, C

    2014-06-01

    The strategy for decreasing volatile organic compound emissions in Mexico has been focused much more on tailpipe emissions than on evaporative emissions, so there is very little information on the contribution of evaporative emissions to the total volatile organic compound inventory. We examined the magnitudes of exhaust and evaporative volatile organic compound emissions, and the species emitted, in a representative fleet of light-duty gasoline vehicles in the Metropolitan Area of Mexico City. The US "FTP-75" test protocol was used to estimate volatile organic compound emissions associated with diurnal evaporative losses, and when the engine is started and a journey begins. The amount and nature of the volatile organic compounds emitted under these conditions have not previously been accounted in the official inventory of the area. Evaporative emissions from light-duty vehicles in the Metropolitan Area of Mexico City were estimated to be 39 % of the total annual amount of hydrocarbons emitted. Vehicles built before 1992 (16 % of the fleet) were found to be responsible for 43 % of the total hydrocarbon emissions from exhausts and 31 % of the evaporative emissions of organic compounds. The relatively high amounts of volatile organic compounds emitted from older vehicles found in this study show that strong emission controls need to be implemented in order to decrease the contribution of evaporative emissions of this fraction of the fleet.

  13. Preventing HIV Transmission among Partners of HIV-Positive Male Sex Workers in Mexico City: A Modeling Study

    PubMed Central

    Monteiro, João Filipe G.; Marshall, Brandon D.L.; Escudero, Daniel; Sosa-Rubí, Sandra G.; González, Andrea; Flanigan, Timothy; Operario, Don; Mayer, Kenneth H.; Lurie, Mark N.; Galárraga, Omar

    2015-01-01

    Mexico has a concentrated HIV epidemic, with male sex workers constituting a key affected population. We estimated annual HIV cumulative incidence among male sex workers’ partners, and then compared incidence under three hypothetical intervention scenarios: improving condom use; and scaling up HIV treatment as prevention, considering current viral suppression rates (CVS, 60.7%) or full viral suppression among those treated (FVS, 100%). Clinical and behavioral data to inform model parameterization were derived from a sample (n=79) of male sex workers recruited from street locations and Clínica Condesa, an HIV clinic in Mexico City. We estimated annual HIV incidence among male sex workers’ partners to be 8.0% (95% CI: 7.3–8.7). Simulation models demonstrated that increasing condom use by 10%, and scaling up HIV treatment initiation by 50% (from baseline values) would decrease the male sex workers-attributable annual incidence to 5.2%, 4.4% (CVS) and 3.2% (FVS), respectively. Scaling up the number of male sex workers on ART and implementing interventions to ensure adherence is urgently required to decrease HIV incidence among male sex workers’ partners in Mexico City. PMID:25307025

  14. Preventing HIV Transmission Among Partners of HIV-Positive Male Sex Workers in Mexico City: A Modeling Study.

    PubMed

    Monteiro, João Filipe G; Marshall, Brandon D L; Escudero, Daniel; Sosa-Rubí, Sandra G; González, Andrea; Flanigan, Timothy; Operario, Don; Mayer, Kenneth H; Lurie, Mark N; Galárraga, Omar

    2015-09-01

    Mexico has a concentrated HIV epidemic, with male sex workers constituting a key affected population. We estimated annual HIV cumulative incidence among male sex workers' partners, and then compared incidence under three hypothetical intervention scenarios: improving condom use; and scaling up HIV treatment as prevention, considering current viral suppression rates (CVS, 60.7 %) or full viral suppression among those treated (FVS, 100 %). Clinical and behavioral data to inform model parameterization were derived from a sample (n = 79) of male sex workers recruited from street locations and Clínica Condesa, an HIV clinic in Mexico City. We estimated annual HIV incidence among male sex workers' partners to be 8.0 % (95 % CI: 7.3-8.7). Simulation models demonstrated that increasing condom use by 10 %, and scaling up HIV treatment initiation by 50 % (from baseline values) would decrease the male sex workers-attributable annual incidence to 5.2, 4.4 % (CVS) and 3.2 % (FVS), respectively. Scaling up the number of male sex workers on ART and implementing interventions to ensure adherence is urgently required to decrease HIV incidence among male sex workers' partners in Mexico City.

  15. Microbiological Implications of Periurban Agriculture and Water Reuse in Mexico City

    PubMed Central

    Mazari-Hiriart, Marisa; Ponce-de-León, Sergio; López-Vidal, Yolanda; Islas-Macías, Pilar; Amieva-Fernández, Rosa Isabel; Quiñones-Falconi, Francisco

    2008-01-01

    Background Recycled treated or untreated wastewater represents an important health challenge in developing countries due to potential water related microbiological exposure. Our aim was to assess water quality and health implications in a Mexico City periurban agricultural area. Methodology/Principal Findings A longitudinal study in the Xochimilco wetland area was conducted, and 42 sites were randomly selected from 211, including irrigation water canals and effluents of treatment plants. Sample collection took place during rainy and dry seasons (2000–2001). Microbiological parameters (total coliforms, fecal coliforms, streptococci/enterococci, and bacteria other than Vibrio grown on TCBS), Helicobacter pylori, and physicochemical parameters including trihalomethanes (THM) were determined. Fecal coliforms and fecal streptococci are appropriate indicators of human or animal fecal contamination. Fecal coliform counts surpass Mexican and World Health Organization irrigation water guidelines. Identified microorganisms associated with various pathologies in humans and domestic animals comprise Escherichia coli, Klebsiella spp., Salmonella spp., Enterobacter spp., Enterococcus spp., and Pseudomonas spp; H. pylori was also present in the water. An environmental characteristic of the canal system showed high Total Organic Carbon content and relatively low dissolved oxygen concentration; residual chlorine as a disinfection control is not efficient, but THMs do not represent a problem. During the rainy season, temperature and conductivity were higher; in contrast, pH, dissolved oxygen, ammonia, and residual chlorine were lower. This is related with the continuous load of feces from human and animal sources, and to the aquatic systems, which vary seasonally and exhibit evidence of lower water quality in effluents from treatment plants. Conclusions/Significance There is a need for improvement of wastewater treatment systems, as well as more efficient monitoring, regulation

  16. Chemical evolution of gaseous air pollutants down-wind of tropical megacities: Mexico City case study

    NASA Astrophysics Data System (ADS)

    Madronich, Sasha

    The photochemical evolution of a polluted air parcel originating in a tropical megacity was modeled for 3 days using a box model with detailed gas-phase chemistry. The parcel was initialized with concentrations typically observed in Mexico City for nitrogen oxides (80 parts per billion on a molar basis, or ppbv), carbon monoxide (3000 ppbv), non-methane hydrocarbons (1700 ppb on a carbon basis, or ppbC) and formaldehyde (23.9 ppbv). Vigorous ozone production occurred during day 1, followed by gradual net destruction during the next 2 days. Other major inorganic products were nitric acid and hydrogen peroxide (35 and 16 ppbv, respectively at the end of day 3), while organic products included ketones (83 ppbv), organic hydroperoxides (25 ppbv), peroxyacyl nitrates (28 ppbv), aldehydes (18 ppbv), organic acids (16 ppbv), alkyl nitrates (10 ppbv) and alcohols (0.2 ppbv). Also produced was multitude of different polyfunctional compounds, present individually at small concentrations, but with significant summed concentrations (68, 49 and 1.5 ppbC, respectively, for compounds having 2, 3 or 4 functional groups), which could contribute to the formation of secondary aerosols. The overall reactivity of the parcel (daytime concentrations of hydroxy, hydroperoxy and organic peroxy radicals; and cumulative hydroxyl radical loss rates) remained relatively constant and high on days 2 and 3. This persistent gas-phase reactivity suggests that urban areas could affect regional and global tropospheric chemistry. However, it remains unclear whether heterogeneous losses, on aerosol particles, reduce this reactivity while simultaneously changing aerosol chemical, microphysical and radiative properties relevant to weather and climate.

  17. Characterization of aerosols containing Zn, Pb, and Cl from an industrial region of Mexico City.

    PubMed

    Moffet, Ryan C; Desyaterik, Yury; Hopkins, Rebecca J; Tivanski, Alexei V; Gilles, Mary K; Wang, Y; Shutthanandan, V; Molina, Luisa T; Abraham, Rodrigo Gonzalez; Johnson, Kirsten S; Mugica, Violeta; Molina, Mario J; Laskin, Alexander; Prather, Kimberly A

    2008-10-01

    Recent ice core measurements show lead concentrations increasing since 1970, suggesting new nonautomobile-related sources of Pb are becoming important worldwide (1). Developing a full understanding of the major sources of Pb and other metals is critical to controlling these emissions. During the March, 2006 MILAGRO campaign, single particle measurements in Mexico City revealed the frequent appearance of particles internally mixed with Zn, Pb, Cl, and P. Pb concentrations were as high as 1.14 microg/m3 in PM10 and 0.76 microg/m3 in PM2.5. Real time measurements were used to select time periods of interest to perform offline analysis to obtain detailed aerosol speciation. Many Zn-rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2 x 6H2O. The internally mixed Pb-Zn-Cl particles represented as much as 73% of the fine mode particles (by number) in the morning hours between 2-5 am. The Pb-Zn-Cl particles were primarily in the submicrometer size range and typically mixed with elemental carbon suggesting a combustion source. The unique single particle chemical associations measured in this study closely match signatures indicative of waste incineration. Our findings also show these industrial emissions play an important role in heterogeneous processing of NO(y) species. Primary emissions of metal and sodium chloride particles emitted by the same source underwent heterogeneous transformations into nitrate particles as soon as photochemical production of nitric acid began each day at approximately 7 am.

  18. Blood lead levels in pregnant women of high and low socioeconomic status in Mexico City.

    PubMed Central

    Farias, P; Borja-Aburto, V H; Rios, C; Hertz-Picciotto, I; Rojas-Lopez, M; Chavez-Ayala, R

    1996-01-01

    This study examined the determinants of blood lead (BPb) in 513 pregnant women in Mexico City: 311 from public hospital prenatal clinics, representing primarily women of low socioeconomic status (SES), and 202 from private hospitals, primarily women of high SES. Overall, BPb levels ranged from 1.38 to 29 micrograms/dl, with geometric means of 6.7 and 11.12 micrograms/dl for women from private and public hospitals, respectively. The crude geometric means difference obtained by t-test was 4.42 (p < 0.001). BPb was measured from January 1994 to August 1995 and showed higher levels during fall and winter and lower levels during spring and summer. The main BPb determinants were the use of lead-glazed ceramics in women from public hospitals and season of the year in women from private hospitals. Consumption of tortillas (corn bread rich in calcium) decreased BPb levels in the lower SES group, but the relationship was not statistically significant (p > 0.05). Consumption of milk products significantly (p < 0.05) reduced BPb levels in the higher SES group. In 112 women whose diets were deficient in calcium, taking calcium supplements lowered their blood lead levels about 7 micrograms/dl. A predictive model fitted to these data, using the strongest predictors plus gestational age, showed a difference of 14 micrograms/dl between the best and worst scenarios in women from public hospitals. Avoiding use of lead-glazed ceramics, consuming diets rich in calcium, and, if needed, taking calcium supplements, would be expected to result in substantial lowering of BPb, especially in pregnant women of low socioeconomic status. Images Figure 1. Figure 2. PMID:8930548

  19. Non-methane hydrocarbons source apportionment at different sites in Mexico City during 2002-2003

    NASA Astrophysics Data System (ADS)

    Vega, E.; Sanchez, G.; Molina, L.

    2007-09-01

    The atmospheric concentrations of a variety of non-methane hydrocarbons (NMHC) collected at different sites, representing urban and rural environments within Mexico City Metropolitan Area (MCMA) during 1997, 2002 and 2003 field campaigns, were compared and used as an input for the Chemical Mass Balance (CMB) receptor model to determine the source contribution of NMHC to the atmosphere. A common feature at all the locations was the dominance of alkenes (59%), aromatics (16%) and olefins (9%) in the average NMHC burden. At the urban sites the interquartile range of NMHC concentrations showed stabilization over this period with a slight increase in the concentrations of propane and butanes in the southwest site of the MCMA in 2003 due to the increased use of liquefied petroleum gas (LPG). The receptor model CMB version 8.0 was used to apportion the NMHC sources at six locations within the MCMA, representing the heavily industrialized, commercial, residential and rural areas. For the 2003 field campaign, the contribution of vehicular emissions dominated the NMHC concentrations (19.7%±7.1% for gasoline vehicles and 35.4%±17.5% for diesel vehicles) followed by the emissions of marketing and handling of LPG (29.9%±8.0%). The NMHC concentrations showed a weekly cycle with the highest levels towards the end of the week and lowest at weekend and beginning of the week, suggesting that both emissions and accumulations process play a key role in building up NMHC levels. The toluene to benzene ratio was used to determine photochemical ageing of the air samples during the 2003 field campaign. The database was divided into periods with similar wind circulation pattern; the results suggest that ageing process within the MCMA is generally suppressed by the amount of fresh emissions.

  20. Prenatal Lead Exposure and Weight of 0- to 5-Year-Old Children in Mexico City

    PubMed Central

    Peterson, Karen E.; Sánchez, Brisa N.; Cantonwine, David; Lamadrid-Figueroa, Héctor; Schnaas, Lourdes; Ettinger, Adrienne S.; Hernández-Avila, Mauricio; Hu, Howard; Téllez-Rojo, Martha M.

    2011-01-01

    Background: Cumulative prenatal lead exposure, as measured by maternal bone lead burden, has been associated with smaller weight of offspring at birth and 1 month of age, but no study has examined whether this effect persists into early childhood. Objective: We investigated the association of perinatal maternal bone lead, a biomarker of cumulative prenatal lead exposure, with children’s attained weight over time from birth to 5 years of age. Methods: Children were weighed at birth and at several intervals up until 60 months. Maternal tibia and patella lead were measured at 1 month postpartum using in vivo K-shell X-ray fluorescence. We used varying coefficient models with random effects to assess the association of maternal bone lead with weight trajectories of 522 boys and 477 girls born between 1994 and 2005 in Mexico City. Results: After controlling for breast-feeding duration, maternal anthropometry, and sociodemographic characteristics, a 1-SD increase in maternal patella lead (micrograms per gram) was associated with a 130.9-g decrease in weight [95% confidence interval (CI), –227.4 to –34.4 g] among females and a 13.0-g nonsignificant increase in weight among males (95% CI, –73.7 to 99.9 g) at 5 years of age. These associations were similar after controlling for concurrent blood lead levels between birth and 5 years. Conclusions: Maternal bone lead was associated with lower weight over time among female but not male children up to 5 years of age. Given that the association was evident for patellar but not tibial lead levels, and was limited to females, results need to be confirmed in other studies. PMID:21715242

  1. Factors associated with condom use in the male population of Mexico City.

    PubMed

    Hernandez-Giron, C A; Cruz-Valdez, A; Quiterio-Trenado, M; Uribe-Salas, F; Peruga, A; Hernández-Avila, M

    1999-02-01

    Sexually transmitted diseases (STDs) are an important public health problem, due to their medical, social and economic repercussions. Therefore, more knowledge is needed about the sexual behaviour that promotes their spread, in order to improve control and prevention strategies. Our aim was to determine the frequency of male condom use associated with sexual behaviour factors, a history of and knowledge about STDs in a sample of the male population in Mexico City. During 1994 a cross-sectional epidemiological study was carried out, using multi-stage sampling with conglomerates, in 1377 men from 15 to 49 years old. The mean age was 34.5 years (SD 7.5 years). Mean age at first sexual relations was 17.7 years (SD 2.8 years). The global proportion of condom use during the last sexual relation was 24.6%; use according to type of female sex partner in the last year was 18.8% with regular partners and 62.5% with occasional partners. The principal predictors of male condom use, identified through statistical modelling, were: younger age (<25 years), middle and high education level (>9 years), middle and high socioeconomic level and type of sexual partners (occasional and regular). This population has risk factors for acquiring and transmitting some STDs, such as occasional sexual partners and a history of STDs. Characteristics which are important in relation to male condom use were identified, such as age (younger than 35), education (complete junior high school or more) and type of sexual partners (occasional and regular).

  2. Effects of ambient ozone on respiratory function and symptoms in Mexico City schoolchildren

    SciTech Connect

    Castillejos, M.; Gold, D.R.; Dockery, D.

    1992-02-01

    The effects of ambient ozone (O3) on respiratory function and acute respiratory symptoms were evaluated in 143 7- to 9-yr-old schoolchildren followed longitudinally at 1- to 2-wk intervals over a period of 6 months at three schools in Pedregal, Mexico City. The maximum O3 level exceeded the World Health Organization guideline of 80 ppb and the U.S. standard of 120 ppb in every week. For an increase from lowest to highest in the mean O3 level during the 48 hr before spirometry (53 ppb), logistic regression estimated relative odds of 1.7 for a child reporting cough/phlegm on the day ofmore » spirometry. For the full population, the mean O3 level during the hour before spirometry, not adjusted for temperature and humidity, predicted a significant decrement in FVC but not in FEV1 or FEF25-75. In contrast, the mean O3 level during the previous 24-, 48-, and 168-h periods predicted significant decrements in FEV1 and FEF25-75 but not in FVC. Ozone was consistently associated with a greater decrement in lung function for the 15 children with chronic phlegm as compared with the children without chronic cough, chronic phlegm, or wheeze. Ozone in the previous 24-, 48-, and 168-h periods predicted decrements in FEV1 for children of mothers who were current or former smokers, but not for children of mothers who were never smokers. Many of these effects were reduced in multiple regression analyses including temperature and humidity, as temperature and O3 were highly correlated.« less

  3. The occurrence and distribution of a group of organic micropollutants in Mexico City's water sources.

    PubMed

    Félix-Cañedo, Thania E; Durán-Álvarez, Juan C; Jiménez-Cisneros, Blanca

    2013-06-01

    The occurrence and distribution of a group of 17 organic micropollutants in surface and groundwater sources from Mexico City was determined. Water samples were taken from 7 wells, 4 dams and 15 tanks where surface and groundwater are mixed and stored before distribution. Results evidenced the occurrence of seven of the target compounds in groundwater: salicylic acid, diclofenac, di-2-ethylhexylphthalate (DEHP), butylbenzylphthalate (BBP), triclosan, bisphenol A (BPA) and 4-nonylphenol (4-NP). In surface water, 11 target pollutants were detected: same found in groundwater as well as naproxen, ibuprofen, ketoprofen and gemfibrozil. In groundwater, concentration ranges of salicylic acid, 4-NP and DEHP, the most frequently found compounds, were 1-464, 1-47 and 19-232 ng/L, respectively; while in surface water, these ranges were 29-309, 89-655 and 75-2,282 ng/L, respectively. Eleven target compounds were detected in mixed water. Concentrations in mixed water were higher than those determined in groundwater but lower than the detected in surface water. Different to that found in ground and surface water, the pesticide 2,4-D was found in mixed water, indicating that some pollutants can reach areas where they are not originally present in the local water sources. Concentration of the organic micropollutants found in this study showed similar to lower to those reported in water sources from developed countries. This study provides information that enriches the state of the art on the occurrence of organic micropollutants in water sources worldwide, notably in megacities of developing countries. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Study of the regional air quality south of Mexico City (Morelos state).

    PubMed

    Salcedo, D; Castro, T; Ruiz-Suárez, L G; García-Reynoso, A; Torres-Jardón, R; Torres-Jaramillo, A; Mar-Morales, B E; Salcido, A; Celada, A T; Carreón-Sierra, S; Martínez, A P; Fentanes-Arriaga, O A; Deustúa, E; Ramos-Villegas, R; Retama-Hernández, A; Saavedra, M I; Suárez-Lastra, M

    2012-01-01

    Results from the first study of the regional air quality in Morelos state (located south of Mexico City) are presented. Criteria pollutants concentrations were measured at several sites within Morelos in February and March of 2007 and 2009; meteorological data was also collected along the state for the same time periods; additionally, a coupled meteorology-chemistry model (Mesoscale Climate Chemistry Model, MCCM) was used to gain understanding on the atmospheric processes occurring in the region. In general, concentrations of almost all the monitored pollutants (O(3), NO(x), CO, SO(2), PM) remained below the Mexican air quality standards during the campaign; however, relatively high concentrations of ozone (8-hour average concentrations above the 60 ppb level several times during the campaigns, i.e. exceeding the World Health Organization and the European Union maximum levels) were observed even at sites with very low reported local emissions. In fact, there is evidence that a large percentage of Morelos vegetation was probably exposed to unhealthy ozone levels (estimated AOT40 levels above the 3 ppm h critical limit). The MCCM qualitatively reproduced ozone daily variations in the sites with an urban component; though it consistently overestimated the ozone concentration in all the sites in Morelos. This is probably because the lack of an updated and detailed emission inventory for the state. The main wind patterns in the region corresponded to the mountain-valley system (downslope flows at night and during the first hours of the day, and upslope flows in the afternoon). At times, Morelos was affected by emissions from surrounding states (Distrito Federal or Puebla). The results are indicative of an efficient transport of ozone and its precursors at a regional level. They also suggest that the state is divided in two atmospheric basins by the Sierras de Tepoztlán, Texcal and Monte Negro. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Aerosol impacts on visible light extinction in the atmosphere of Mexico City.

    PubMed

    Eidels-Dubovoi, Silvia

    2002-03-27

    Eleven diurnal aerosol visible light absorption and scattering patterns were obtained from measurements done with an aethalometer and an integrating nephelometer during 28 February-10 March 1997 at two different sites in the Mexico City basin. Both measurement sites, the Merced site affected by regional and urban-scale aerosol and the Pedregal site dominated by regional-scale aerosol, showed a variety of diurnal light absorption and scattering patterns. For the majority of the 11 studied days, the highest absorption peaks appeared in the early morning, 07.00-09.30 h while those of scattering appeared later, 09.30-11.00 h. The earlier absorption peaks could be attributed to the elevated elemental carbon vehicular emissions during the heavy traffic hours whereas the later scattering peaks could be attributed to secondary aerosols formed photochemically in the atmosphere. During the period examined, the Pedregal site exhibited on the average a lower aerosol scattering and a higher aerosol absorption contribution to the total aerosol visible light extinction and a better visibility than that of the Merced site. Hence, the impact of aerosol absorption on the visibility degradation due to aerosols was greater at the less hazy Pedregal site. The overall 11-day aerosol visibility average of 20.9 km found at La Merced site, was only 9.4 km lower than that of 30.3 km found at the Pedregal site. This small aerosol visibility difference, of the order of the standard deviation, led to the conclusion that besides the regional-scale aerosol impact, the urban-scale aerosol impact on aerosol visible light extinction is very similar at La Merced and Pedregal sites.

  6. Obesity, eating behaviour and mental health among university students in Mexico City.

    PubMed

    Lazarevich, Irina; Irigoyen-Camacho, María Esther; Velázquez-Alva, María del Consuelo

    2013-11-01

    Psychological factors are important in the development of obesity; however these are frequently underestimated in intervention programs. To examine the association of mental health with altered eating behavior related to weigh gain, and with abdominal obesity among college students in order to provide more comprehensive guidelines for intervention programs. A cross-sectional study was performed with 1,122 university students (from a total population of 1,820 freshmen students) at the Metropolitan Autonomous University, Mexico City. Body mass index and waist circumference (WC) were recorded. A six items questionnaire was applied to assess altered eating behavior. Self-reported questionnaires for depression (Beck Depression Inventory), anxiety (General Anxiety Disorder Scale of Carrol and Davidson), and impulsiveness symptoms (Plutchik Impulsivity Scale) were used. Multiple logistic regression models were performed. An increased WC was associated with depression symptoms (OR=1.4), female sex (OR=1.5), and age (OR=1.1). Students with altered eating behaviors showed elevated levels of impulsivity (e.g. have difficulties to stop eating, OR=4.2) and depression (e.g. have problem to eat at regular times, OR=6.98). In addition, higher WC was associated with female sex, parents' obesity, and unhealthy eating behaviors (e.g. have difficulties to stop eating, OR=1.42; and constantly feel hungry, and eat too much, OR=2.25). Although preventive programs directed at development of adequate eating habits and physical activity are considered a key component of intervention programs, strategies for the management of emotions, the promotion of positive mood and impulsivity-reduction techniques are a necessary complement for a comprehensive approach to overweight and obesity. Copyright AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  7. Ozone production, nitrogen oxides, and radical budgets in Mexico City: observations from Pico de Tres Padres

    NASA Astrophysics Data System (ADS)

    Wood, E. C.; Herndon, S. C.; Onasch, T. B.; Kroll, J. H.; Canagaratna, M. R.; Kolb, C. E.; Worsnop, D. R.; Neuman, J. A.; Seila, R.; Zavala, M.; Knighton, W. B.

    2008-08-01

    Observations at a mountain-top site within the Mexico City basin are used to characterize ozone production and destruction, the nitrogen oxide budget, and the radical budget during the MILAGRO campaign. An ozone production rate of ~50 ppbv/h was observed in a stagnant air mass during the afternoon of 12 March 2006, which is among the highest observed anywhere in the world. Approximately half of the ozone destruction was due to the oxidation of NO2. During this time period ozone production was VOC-limited, deduced by a comparison of the radical production rates and the formation rate of NOx oxidation products (NOz) For [NOx]/[NOy] values between 0.2 and 0.8, gas-phase HNO3 typically accounted for less than 10% of NOz and accumulation-mode particulate nitrate (NO3-(PM)) accounted for 20% 70% of NOz, consistent with high ambient NH3 concentrations. The fraction of NOz accounted for by the sum of HNO3(g) and NO3-(PM) decreased with photochemical processing. This decrease is apparent even when dry deposition of HNO3 is accounted for, and indicates that HNO3 formation decreased relative to other NOx "sink" processes during the first 12 h of photochemistry and/or a significant fraction of the nitrate was associated with the coarse aerosol size mode. The ozone production efficiency of NOx on 11 and 12 March 2006 was approximately 7 on a time scale of one day. A new metric for ozone production efficiency that relates the dilution-adjusted ozone mixing ratio to cumulative OH exposure is proposed.

  8. Nasal cytology in southwest metropolitan Mexico City inhabitants: a pilot intervention study.

    PubMed Central

    Calderon-Garcidueñas, L; Roy-Ocotla, G

    1993-01-01

    Southwest metropolitan Mexico City (SWMMC) inhabitants have been exposed several hours per day for the last 6 years to photochemical smog, ozone being the most important oxidant pollutant. Subjects exposed to the SWMMC atmosphere develop several histopathological changes in their nasal mucosa: dysplasia is the most significant, affecting 78.72% of adult individuals within 60 or more days of residence in SWMMC. This study was originally designed to explore whether chemical intervention could modify nasal dysplasia, as determined by nasal cytology, in a defined adult population. In a placebo-controlled, randomized, double-blind trial, 177 healthy male subjects were divided into 5 groups to whom 5000 IU of vitamin A, 100 IU of vitamin E, a combination of vitamins A and E (5000 IU + 100 IU), 16 mg of beta-carotene, or placebo were administered daily for 4 months. Sixteen clinical and cytological variables were monitored. No effect on dysplasia was seen at the end of the 4-month trial; however, an apparent reversibility as well as progression of the dysplastic nasal lesions and high correlation coefficients between dysplasia and nasal cytology of polymorphonuclear leukocytes (PMNs; 0.85), squamous metaplasia (SM; 0.50), and nasal mucosa atrophy (NMA; 0.41) were found. A mathematical theoretical nasal dysplasia (tD) predictor equation for SWMMC adult male inhabitants is proposed (tD = 0.85 delta PMNs + 0.50 delta SM + 0.41 delta NMA + 0.98), in which PMNs are the best single dysplasia predictor, and all variables are independent.(ABSTRACT TRUNCATED AT 250 WORDS) Images p138-a Figure 1. Figure 2. Figure 3. Figure 4. PMID:8354200

  9. Microbiological implications of periurban agriculture and water reuse in Mexico City.

    PubMed

    Mazari-Hiriart, Marisa; Ponce-de-León, Sergio; López-Vidal, Yolanda; Islas-Macías, Pilar; Amieva-Fernández, Rosa Isabel; Quiñones-Falconi, Francisco

    2008-05-28

    Recycled treated or untreated wastewater represents an important health challenge in developing countries due to potential water related microbiological exposure. Our aim was to assess water quality and health implications in a Mexico City periurban agricultural area. A longitudinal study in the Xochimilco wetland area was conducted, and 42 sites were randomly selected from 211, including irrigation water canals and effluents of treatment plants. Sample collection took place during rainy and dry seasons (2000-2001). Microbiological parameters (total coliforms, fecal coliforms, streptococci/enterococci, and bacteria other than Vibrio grown on TCBS), Helicobacter pylori, and physicochemical parameters including trihalomethanes (THM) were determined. Fecal coliforms and fecal streptococci are appropriate indicators of human or animal fecal contamination. Fecal coliform counts surpass Mexican and World Health Organization irrigation water guidelines. Identified microorganisms associated with various pathologies in humans and domestic animals comprise Escherichia coli, Klebsiella spp., Salmonella spp., Enterobacter spp., Enterococcus spp., and Pseudomonas spp; H. pylori was also present in the water. An environmental characteristic of the canal system showed high Total Organic Carbon content and relatively low dissolved oxygen concentration; residual chlorine as a disinfection control is not efficient, but THMs do not represent a problem. During the rainy season, temperature and conductivity were higher; in contrast, pH, dissolved oxygen, ammonia, and residual chlorine were lower. This is related with the continuous load of feces from human and animal sources, and to the aquatic systems, which vary seasonally and exhibit evidence of lower water quality in effluents from treatment plants. There is a need for improvement of wastewater treatment systems, as well as more efficient monitoring, regulation, and enforcement procedures for wastewater disposal into bodies of

  10. Mexico.

    PubMed

    1988-02-01

    Focus in this discussion of Mexico is on the following: geography; the people; history; political conditions; the economy; foreign relations; and relations between the US and Mexico. As of July 1987, the population of Mexico numbered 81.9 million with an estimated annual growth rate of 2.09%. 60% of the population is Indian-Spanish (mestizo), 30% American Indian, 9% white, and 1% other. Mexico is the most populous Spanish-speaking country in the world and the 2nd most populous country in Latin America. Education is decentralized and expanded. Mexico's topography ranges from low desert plains and jungle-like coastal strips to high plateaus and rugged mountains. Hernan Cortes conquered Mexico in 1919-21 and founded a Spanish colony that lasted for almost 300 years. Independence from Spain was proclaimed by Father Miguel Hidalgo on September 16, 1810; the republic was established on December 6, 1822. Mexico's constitution of 1917 provides for a federal republic with a separation of powers into independent executive, legislative, and judicial branches of government. Significant political themes of the administration of President Miguel de la Madrid Hurtado, who began his 6-year term in 1982, have been restructuring the economy, liberalizing trade practices, decentralizing government services, and eliminating corruption among public servants. In 1987, estimates put the real growth of the Mexican economy at 1.5%; the gross domestic product (GDP) had shrunk by 3.5% in 1986. Yet, on the positive side, Mexico's international reserves increased to record levels in 1987 (to about $15 billion), and its current account surplus reached more than $3 billion. Mexico has made considerable progress in moving to restructure its economy. It has substantially reduced impediments to international trade and has moved to reduce the number of parastatal firms. 1987 was the 2nd consecutive year in which Mexico recorded triple-digit inflation; inflation reached 158.8%. Other problems include

  11. A benefit-cost analysis of retrofitting diesel vehicles with particulate filters in the Mexico City metropolitan area.

    PubMed

    Stevens, Gretchen; Wilson, Andrew; Hammitt, James K

    2005-08-01

    In the Mexico City metropolitan area, poor air quality is a public health concern. Diesel vehicles contribute significantly to the emissions that are most harmful to health. Harmful diesel emissions can be reduced by retrofitting vehicles with one of several technologies, including diesel particulate filters. We quantified the social costs and benefits, including health benefits, of retrofitting diesel vehicles in Mexico City with catalyzed diesel particulate filters, actively regenerating diesel particulate filters, or diesel oxidation catalysts, either immediately or in 2010, when capital costs are expected to be lower. Retrofit with either type of diesel particulate filter or an oxidation catalyst is expected to provide net benefits to society beginning immediately and in 2010. At current prices, retrofit with an oxidation catalyst provides greatest net benefits. However, as capital costs decrease, retrofit with diesel particulate filters is expected to provide greater net benefits. In both scenarios, retrofit of older, dirtier vehicles that circulate only within the city provides greatest benefits, and retrofit with oxidation catalysts provides greater health benefits per dollar spent than retrofit with particulate filters. Uncertainty about the magnitude of net benefits of a retrofit program is significant. Results are most sensitive to values used to calculate benefits, such as the concentration-response coefficient, intake fraction (a measure of exposure), and the monetary value of health benefits.

  12. PREVALENCE AND CORRELATES OF CLIENT-PERPETRATED ABUSE AMONG FEMALE SEX WORKERS IN TWO MEXICO-U.S. BORDER CITIES

    PubMed Central

    Ulibarri, Monica D.; Strathdee, Steffanie A.; Lozada, Remedios; Magis-Rodriguez, Carlos; Amaro, Hortensia; O'Campo, Patricia; Patterson, Thomas L.

    2011-01-01

    History of abuse has been associated with greater HIV risk among women. This study examined client-perpetrated abuse among female sex workers (FSWs) in two Mexico-U.S. border cities where HIV prevalence is rising. Among 924 FSWs, prevalence of client-perpetrated abuse was 31%. In multivariate logistic regression models, intimate partner violence, psychological distress and having drug-using clients were associated with experiencing client-perpetrated abuse. FSWs along the Mexico-U.S. border report frequently experiencing abuse from both clients and intimate partners, which may have serious mental health consequences. Our findings suggest the need for screening and gender-based violence prevention services for Mexican FSWs. PMID:24686125

  13. Parent Management Training-Oregon Model (PMTO™) in Mexico City: Integrating Cultural Adaptation Activities in an Implementation Model.

    PubMed

    Baumann, Ana A; Domenech Rodríguez, Melanie M; Amador, Nancy G; Forgatch, Marion S; Parra-Cardona, J Rubén

    2014-03-01

    This article describes the process of cultural adaptation at the start of the implementation of the Parent Management Training intervention-Oregon model (PMTO) in Mexico City. The implementation process was guided by the model, and the cultural adaptation of PMTO was theoretically guided by the cultural adaptation process (CAP) model. During the process of the adaptation, we uncovered the potential for the CAP to be embedded in the implementation process, taking into account broader training and economic challenges and opportunities. We discuss how cultural adaptation and implementation processes are inextricably linked and iterative and how maintaining a collaborative relationship with the treatment developer has guided our work and has helped expand our research efforts, and how building human capital to implement PMTO in Mexico supported the implementation efforts of PMTO in other places in the United States.

  14. Parent Management Training-Oregon Model (PMTO™) in Mexico City: Integrating Cultural Adaptation Activities in an Implementation Model

    PubMed Central

    Baumann, Ana A.; Domenech Rodríguez, Melanie M.; Amador, Nancy G.; Forgatch, Marion S.; Parra-Cardona, J. Rubén

    2015-01-01

    This article describes the process of cultural adaptation at the start of the implementation of the Parent Management Training intervention-Oregon model (PMTO) in Mexico City. The implementation process was guided by the model, and the cultural adaptation of PMTO was theoretically guided by the cultural adaptation process (CAP) model. During the process of the adaptation, we uncovered the potential for the CAP to be embedded in the implementation process, taking into account broader training and economic challenges and opportunities. We discuss how cultural adaptation and implementation processes are inextricably linked and iterative and how maintaining a collaborative relationship with the treatment developer has guided our work and has helped expand our research efforts, and how building human capital to implement PMTO in Mexico supported the implementation efforts of PMTO in other places in the United States. PMID:26052184

  15. Prevalence and correlates of client-perpetrated abuse among female sex workers in two Mexico-U.S. border cities.

    PubMed

    Ulibarri, Monica D; Strathdee, Steffanie A; Lozada, Remedios; Magis-Rodriguez, Carlos; Amaro, Hortensia; O'Campo, Patricia; Patterson, Thomas L

    2014-04-01

    History of abuse has been associated with greater HIV risk among women. This study examined client-perpetrated abuse among female sex workers (FSWs) in two Mexico-U.S. border cities where HIV prevalence is rising. Among 924 FSWs, prevalence of client-perpetrated abuse was 31%. In multivariate logistic regression models, intimate partner violence (IPV), psychological distress, and having drug-using clients were associated with experiencing client-perpetrated abuse. FSWs along the Mexico-U.S. border report frequently experiencing abuse from both clients and intimate partners, which may have serious mental health consequences. Our findings suggest the need for screening and gender-based violence prevention services for Mexican FSWs.

  16. Obesity increases metabolic syndrome risk factors in school-aged children from an urban school in Mexico city.

    PubMed

    Perichart-Perera, Otilia; Balas-Nakash, Margie; Schiffman-Selechnik, Esther; Barbato-Dosal, Annarella; Vadillo-Ortega, Felipe

    2007-01-01

    To characterize the nutritional status of school-aged children from an urban public school in Mexico City, Mexico, and to assess the influence of obesity on health status in a subgroup of these children. Cross-sectional descriptive study. A nutrition screening was done for all children, including anthropometric (ie, weight, height, and waist circumference) and blood pressure assessment. In the subgroup of children, complementary dietary and biochemical assessment (ie, glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, insulin, albumin, hemoglobin, and hematocrit levels) was done. Children from an urban school in Mexico City (N=561) aged 6 to 13 years. The representative subgroup (n=88) was selected based on age (9 to 12 years) and weight status (ie, normal, overweight, or obese). Descriptive statistics, correlations, mean differences tests (analysis of variance, Kruskal-Wallis and Mann-Whitney U), and chi(2) tests (categorical variables) were done with SPSS version 13 (2005, SPSS Inc, Chicago, IL). In the whole school, overweight and obesity prevalence were 27.1% and 21.4%, respectively. High systolic blood pressure was seen in 8.4% of children and 6.2% of children had prehypertension. Higher hypertension risk was seen in children with body mass index > or =95th percentile and waist circumference > or =90th percentile (88 cm). Significantly higher waist circumference, systolic blood pressure, insulin resistance indexes, and triglyceride levels were found among the obese when compared with normal-weight children. Childhood obesity prevalence is high in Mexico and it is having an influence on children's health. It is urgent to design, implement, and evaluate specific childhood obesity prevention programs.

  17. In depth analysis of the role of the mountain gap south of the Valley of Mexico on the air quality in Mexico City.

    NASA Astrophysics Data System (ADS)

    Gerardo Ruiz Suarez, Luis

    2010-05-01

    38 days of air quality observations in Tenango del Aire (TENAI), south of Mexico City during MILAGRO were analyzed. That site was managed by FQA-CCA-UNAM's team with a mobile laboratory equipped with standard air quality monitors: O3, NOx, NOy, CO, SO2 and surface meteorological parameters. Hosted additional instruments were: CH2O, column NO2 (DOAS), backscatter (Lidar) and pilot balloons. Also, an ultra light plane from IMK-IFU, equipped with O3, PM10, CN, Dew Point monitors flew around the Popocatepetl and Iztaccihuatl volcanoes and above of TENAI some days during MILAGRO. Atop of TENAI, the ultra light descended in spiral until near ground and ascended to resume its path. In addition to these measurements, UNAM team ran air quality numerical simulations using the Mesoscale Climate and Chemistry Model (MCCM) and an online coupled Wind Erosion Processor to MCCM we call WEPS-MCCM. The combined observations on the ground, the ultra light plane and the models results enabled us to carry out an in depth analysis of air quality in such important region south of Mexico City. Comparison were made with the episodes classification proposed by De Foy; Ozone North and South, Convection North and South, Cold Surge and South Venting to characterize dynamics in the Valley of Mexico. The aim was to define how well connected is TENAI with the air quality network in the MCMA. The influence of the mountain gap on ozone and PM10 levels in Mexico City is analyzed by episode type. Also, the impact of the mega city of Mexico on the nearby region to the south can be understood by observations in TENAI. More polluted episode types in TENAI are those called: Cold Surge, Ozone South and South Venting due to a wind shift occurring in early afternoon that brings back polluted air that was drained south during the morning and returns back to TENAI rich in aged air parcels. March 17 was chosen to show the integrated analysis of all variables observed and modeled (MCCM) in TENAI. In that day

  18. Contribution of biomass burning to particles matter smaller than ten microns in Mexico City during April 2013.

    NASA Astrophysics Data System (ADS)

    Mendoza Campos, Alejandra; Agustin Garcia Reynoso, Jóse; Castro Romero, Telma; Carbajal Perez, Jóse Noel; Gerardo Ruiz Suarez, Luis; Peralta Rosales, Oscar Augusto

    2015-04-01

    A forest fire is a natural combustion process in a specific geographic area, it's depends on meteorological variables, topography and vegetation type, The wildfires are potential sources of large amounts of pollutants. The main air pollutants emitted in a forest fire are the particles (PM10 and PM2.5) Carbon Monoxide (CO), Nitrogen Oxides (NOx), Volatile Organic Compounds (VOCs) and a negligible amount of Sulfur Dioxide (SO2) (Chow 1995), The study of the impact of air quality in Mexico City for a forest fire occurred on April 14 of 2013 was conducted a duration of 26 hours of grassland burning and consuming an extension of 150 ha, the WRF-Chem, WRF-fire and METv3 models were used to perform the study, for the study two modeling were made, one including emissions from forest fires and the other one no emission-fire, when interpolation is made between the two modeling and obtained the impact of air quality in Mexico City, performing calculating emissions and modeling, the impact on air quality for PM10particles were observed arriving at a concentration of 350 mg/m3 due to wildfire occurred, this issue exceeds the maximum permissible limit of PM10particles governed by NOM-025-SSA1-1993 that establishes a maximum of 120 mg/m3 on average for 24 hours, the modeling results with measured data is corroborated weather Stations the environmental monitoring network of the Mexico City, that alerts an environmental contingency for particles for the post-wildfire day. Until now is review the rule which establishes a maximum of 75 mg/m3 on average for 24 hours, implying greater involvement in air quality.

  19. Exploring Migratory Dynamics on HIV Transmission: The Case of Mexicans in New York City and Puebla, Mexico

    PubMed Central

    Guilamo-Ramos, Vincent; McCarthy, Katharine; Muñoz-Laboy, Miguel A.; de Lourdes Rosas López, Maria

    2014-01-01

    Migration and population movement are increasingly viewed as important factors associated with HIV transmission risk. With growing awareness of the potential impact of migration on HIV transmission, several perspectives have emerged that posit differing dynamics of risk. We considered available data on the role of migration on HIV transmission among Mexican migrants in New York City and Puebla, Mexico. Specifically, we examined 3 distinct models of migratory dynamics of HIV transmission—namely, the structural model, the local contextual model, and the interplay model. In doing so, we reframed current public health perspectives on the role of migration on HIV transmission. PMID:24825203

  20. Bloodstream infections and inpatient length of stay among pediatric cancer patients with febrile neutropenia in Mexico City.

    PubMed

    Avilés-Robles, Martha; Ojha, Rohit P; González, Miriam; Ojeda-Diezbarroso, Karla; Dorantes-Acosta, Elisa; Jackson, Bradford E; Johnson, Kyle M; Caniza, Miguela A

    2014-11-01

    We assessed the association between bloodstream infections (BSIs) and inpatient length of stay among pediatric cancer patients with febrile neutropenia in Mexico City. The estimated length of stay for BSIs was 19 days, which corresponded with a 100% (95% confidence limits, 60%-160%) relative increase in the length of stay compared with patients for whom no pathogen was identified. Feasible options for reducing the length of stay should be considered to alleviate patient and resource burden. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  1. Popular Health Education and Propaganda in Times of Peace and War in Mexico City, 1890s–1920s

    PubMed Central

    Agostoni, Claudia

    2006-01-01

    Health education and propaganda acquired importance during the late 19th and early 20th centuries in Mexico City, as physicians, hygienists, and schoolteachers attempted to teach the principles of public health to a culturally and socially heterogeneous urban population. I explore the organization of the Popular Hygiene Exhibition of 1910 and the importance of health education before and after the armed phase of the Mexican Revolution, and why children and the indigenous populations became the main recipients of health education programs. PMID:16322465

  2. [A remedy against delinquency: child labour in lock-up institutions in post-revolutionary Mexico City].

    PubMed

    Sosenski, S

    2008-01-01

    In post-revolutionary Mexico City, work therapy prevailed over other treatments used to correct what was considered a social disease: child delinquency. Thousands of children took up the fields of farm schools as well as workshops in reformatories and industrial schools. The manual labor carried out by children of the popular sectors was used in childhood establishments as a way to make up for what they received in those places. Based on the logic that work as regenerator of a sick body and an ill mind, the Mexican state tried to turn the young delinquents into the future workers.

  3. First record of Hesperolabops nigriceps Reuter (Hemiptera: Miridae) on Opuntia ficus-indica in Milpa Alta, Mexico City.

    PubMed

    Palomares-Pérez, Martín; Rodríguez-Leyva, Esteban; Brailovsky, Harry; Ramírez-Alarcón, Samuel

    2010-01-01

    In recent years a species of Hesperolabops has become a problem as a pest of nopalitos, Opuntia ficus-indica, in Milpa Alta, in the south of Mexico City, which is the most important production region of this vegetable in the country. A survey of Hesperolabops in Milpa Alta has resulted in the first report of Hesperolabops nigriceps Reuter. This occurrence should be monitored and considered in future studies in order to avoid misidentification of Hesperolabops spp. Kirkaldy native populations there, and to avoid the confusion of the damage that may be caused on O. ficus-indica.

  4. Subsidence Induced by Underground Extraction

    USGS Publications Warehouse

    Galloway, Devin L.

    2016-01-01

    Subsidence induced by underground extraction is a class of human-induced (anthropogenic) land subsidence that principally is caused by the withdrawal of subsurface fluids (groundwater, oil, and gas) or by the underground mining of coal and other minerals.

  5. Family context and individual situation of teens before, during and after pregnancy in Mexico City.

    PubMed

    Sámano, Reyna; Martínez-Rojano, Hugo; Robichaux, David; Rodríguez-Ventura, Ana Lilia; Sánchez-Jiménez, Bernarda; de la Luz Hoyuela, Maria; Godínez, Estela; Segovia, Selene

    2017-11-16

    In the last 20 years, adolescent pregnancy has become one of the most critical problems affecting women in Latin America and the Caribbean. This qualitative study was based on in-depth interviews with 29 teen mothers. All of the pregnant teens were from low- to lower-middle-class social strata in the Mexico City metropolitan area. The family (living with the girl) and the individual context of pregnant teens were analysed on the basis of data from at least three interviews: during pregnancy and at approximately 6 and 24 months following delivery. Additionally, six mothers, four fathers, and four partners of the pregnant girls of the group were interviewed. The information on the individual and family situation before, during and after the pregnancy was recorded and transcribed, then analysed in three phases, comprising pre-analysis, exploration and interpretation. The pregnant teens had a family background of teen pregnancy. The girls disclosed feelings of repression, loneliness and indifference to their parents, leading them to unprotected sexual relations without fear of pregnancy. After the pregnancy, communication improved between the girls and their parents, but became worse with their partner. Consequently, these teens returned to feeling as they did before getting pregnant. They stated that they would make their situation work for the sake of their child, and regretted dropping out of school and getting pregnant so young. Almost all said they were seeking love outside the family, which revealed a scenario of limited communication and unsatisfactory relations within the family. Understanding how communication works between parents and children is necessary to avoid teenage pregnancy, as well as early marriage or cohabitation, resulting in dropping out of school and financial constraints, which lead to great frustrations between the couple and affects the child. In addition, it is vitally important that adolescents be motivated in the family setting in order

  6. Contribution of Biomass Burning to Carbonaceous Aerosols in Mexico City during may 2013

    NASA Astrophysics Data System (ADS)

    Tzompa Sosa, Z. A.; Sullivan, A.; Kreidenweis, S. M.

    2014-12-01

    The Mexico City Metropolitan Area (MCMA) is one of the largest megacities in the world with a population of 20 million people. Emissions transported from outside the basin, such as wildfires and agricultural burning, represent a potentially large contribution to air quality degradation. This study analyzed PM10 filter samples from six different stations located across the MCMA from May, 2013, which represented the month with the most reported fire counts in the region between 2002-2013. Two meteorological regimes were established considering the number of satellite derived fire counts, changes in predominant wind direction, ambient concentrations of CO, PM10 and PM2.5, and precipitation patterns inside MCMA. The filter samples were analyzed for biomass burning tracers including levoglucosan (LEV), water-soluble potassium (WSK+); and water-soluble organic carbon (WSOC). Results of these analyses show that LEV concentrations correlated positively with ambient concentrations of PM2.5 and PM10 (R2=0.61 and R2=0.46, respectively). Strong correlations were also found between WSOC and LEV (R2=0.94) and between WSK+ and LEV (R2=0.75). An average LEV/WSOC ratio of 0.0147 was estimated for Regime 1 and 0.0062 for Regime 2. Our LEV concentrations and LEV/WSOC ratios are consistent with results found during the MILAGRO campaign (March, 2006). To the best of our knowledge, only total potassium concentrations have been measured in aerosol samples from MCMA. Therefore, this is the first study in MCMA to measure ambient concentrations of WSK+. Analysis of gravimetric mass concentrations showed that PM2.5 accounted for 60% of the PM10 mass concentration with an estimated PM10/PM2.5 ratio of 1.68. Estimates from our laboratory filter sample characterization indicated that we measured 37% of the total PM10 mass concentration. The missing mass is most likely crustal material (soil or dust) and carbonaceous aerosols that were not segregated into WSOC fraction. Assuming that LEV is

  7. Temporal and spatial variation of morphological descriptors for atmospheric aerosols collected in Mexico City

    NASA Astrophysics Data System (ADS)

    China, S.; Mazzoleni, C.; Dubey, M. K.; Chakrabarty, R. K.; Moosmuller, H.; Onasch, T. B.; Herndon, S. C.

    2010-12-01

    We present an analysis of morphological characteristics of atmospheric aerosol collected during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign that took place in Mexico City in March 2006. The sampler was installed on the Aerodyne mobile laboratory. The aerosol samples were collected on nuclepore clear polycarbonate filters mounted in Costar pop-top membrane holders. More than one hundred filters were collected at different ground sites with different atmospheric and geographical characteristics (urban, sub-urban, mountain-top, industrial, etc.) over a month period. Selected subsets of these filters were analyzed for aerosol morphology using a scanning electron microscope and image analysis techniques. In this study we investigate spatial and temporal variations of aerosol shape descriptors, morphological parameters, and fractal dimension. We also compare the morphological results with other aerosol measurements such as aerosol optical properties(scattering and absorption) and size distribution data. Atmospheric aerosols have different morphological characteristics depending on many parameters such as emission sources, atmospheric formation pathways, aging processes, and aerosol mixing state. The aerosol morphology influences aerosol chemical and mechanical interactions with the environment, physical properties, and radiative effects. In this study, ambient aerosol particles have been classified in different shape groups as spherical, irregularly shaped, and fractal-like aggregates. Different morphological parameters such as aspect ratio, roundness, feret diameter, etc. have been estimated for irregular shaped and spherical particles and for different kinds of soot particles including fresh soot, collapsed and coated soot. Fractal geometry and image processing have been used to obtain morphological characteristics of different soot particles. The number of monomers constituting each aggregate and their diameters were

  8. Em