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Sample records for leones mexico city

  1. Observations of ozone-induced foliar injury on black cherry (Prunus serotina, var. capuli) within the Desierto de Los Leones National Park, Mexico City.

    Science.gov (United States)

    Skelly, J M; Savage, J E; de Bauer, M de L; Alvarado, D

    1997-01-01

    A survey for ozone-induced foliar injury of black cherry was conducted in mid-June 1995 within the Desierto de Los Leones National Park located southwest of Mexico City. Evaluations of the upper and lower tree crowns of 18 trees revealed evidence of significant upper surface stipple, leaf reddening and premature senescence on 72% of the trees. A general survey of an additional 169 trees disclosed that 41% exhibited similar symptoms. A gradient of increasing symptoms with increasing elevation was also evident. For the most part, asymptomatic trees were observed to be situated within well-shaded coves at the lower elevations with very few symptomatic trees present in these areas.

  2. September 1985 Mexico City, Mexico Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The magnitude 8.1 earthquake occurred off the Pacific coast of Mexico. The damage was concentrated in a 25 square km area of Mexico City, 350 km from the epicenter....

  3. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    International Nuclear Information System (INIS)

    Méndez-García, C.; Montero-Cabrera, M. E.; Renteria-Villalobos, M.; García-Tenorio, R.

    2014-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232 Th-series, 238 U-series, 40 K and 137 Cs activity concentrations (AC, Bq kg −1 ) were determined by gamma spectrometry with a high purity Ge detector. 238 U and 234 U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210 Pb activities. Results were verified by 137 Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238 U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234 U/ 238 U and 238 U/ 226 Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232 Th/ 238 U, 228 Ra/ 226 Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs

  4. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Science.gov (United States)

    Méndez-García, C.; Renteria-Villalobos, M.; García-Tenorio, R.; Montero-Cabrera, M. E.

    2014-07-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232Th-series, 238U-series, 40K and 137Cs activity concentrations (AC, Bq kg-1) were determined by gamma spectrometry with a high purity Ge detector. 238U and 234U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210Pb activities. Results were verified by 137Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento - Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234U/overflow="scroll">238U and 238U/overflow="scroll">226Ra in sediments have values between 0.9-1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232Th/overflow="scroll">238U, 228Ra/overflow="scroll">226Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  5. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Méndez-García, C.; Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, CIMAV, Miguel de Cervantes 120, 31109, Chihuahua, Chihuahua (Mexico); Renteria-Villalobos, M. [Facultad de Zootecnia y Ecología Universidad Autónoma de Chihuahua, Periferico Francisco R. Almada Km 1, 31410, Chihuahua (Mexico); García-Tenorio, R. [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2008-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. ²³²Th-series, ²³⁸U-series, ⁴⁰K and ¹³⁷Cs activity concentrations (AC, Bq kg⁻¹) were determined by gamma spectrometry with a high purity Ge detector. ²³⁸U and ²³⁴U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to ²¹⁰Pb activities. Results were verified by ¹³⁷Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High ²³⁸U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) ²³⁴U/²³⁸U and ²³⁸U/²²⁶Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. ²³²Th/²³⁸U, ²²⁸Ra/²²⁶Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  6. [Effects of reforestation on tree pollen sensitization in inhabitants of Nuevo Leon, Mexico].

    Science.gov (United States)

    Palma-Gómez, Samuel; González-Díaz, Sandra Nora; Arias-Cruz, Alfredo; Macías-Weinmann, Alejandra; Amaro-Vivian, Laura Elizabeth; Pérez-Vanzzini, Rafael; Gutiérrez-Mujica, José Julio; Yong-Rodríguez, Adrián

    2014-01-01

    Climate change has implications for health, ecology and society. Urban green areas are a key element in the planning of cities, promoting citizen interaction with the environment, as well as health. Lack of planning and design of these areas as well as the selection of ornamental trees can be a trigger of pollen allergy in the surrounding population. Reforestation is among the programs implemented by the government that have an impact on allergy. Environmental reforestation programs do not take into account the allergenic potential of some species. In the last 4 years, the government of Nuevo Leon, Mexico, has planted nearly 18,000 Quercus species trees, in addition to an unknown number of Fraxinus species trees that are listed as tree species with high pollen production. To identify changes in tree pollen sensitization, based on environmental reforestation programs. A retrospective and descriptive study was done in which positive skin prick tests to pollen from trees in the interval of 2010-2014 were analyzed, correlating between tree species used for reforestation and increased sensitivity to the former. A statistically significant increase in pollen sensitization to species with which Nuevo Leon was reforested was found, along with a decrease in sensitization to the species that were not reforested. Reforestation contributes to some extent to the change in the pattern of positive skin tests and may result in more frequent exacerbations of respiratory diseases. It is an activity that should always be regulated and assisted by experts in the according field.

  7. Updated comparison of groundwater flow model results and isotopic data in the Leon Valley, Mexico

    Science.gov (United States)

    Hernandez-Garcia, G. D.

    2015-12-01

    Northwest of Mexico City, the study area is located in the State of Guanajuato. Leon Valley has covered with groundwater its demand of water, estimated in 20.6 cubic meters per second. The constant increase of population and economic activities in the region, mainly in cities and automobile factories, has also a constant growth in water needs. Related extraction rate has produced an average decrease of approximately 1.0 m per year over the past two decades. This suggests that the present management of the groundwater should be checked. Management of groundwater in the study area involves the possibility of producing environmental impacts by extraction. This vital resource under stress becomes necessary studying its hydrogeological functioning to achieve scientific management of groundwater in the Valley. This research was based on the analysis and integration of existing information and the field generated by the authors. On the base of updated concepts like the geological structure of the area, the hydraulic parameters and the composition of deuterium-delta and delta-oxygen -18, this research has new results. This information has been fully analyzed by applying a groundwater flow model with particle tracking: the result has also a similar result in terms of travel time and paths derived from isotopic data.

  8. Learning Styles and Attitudes toward Online Education in Four Universities in the State of Nuevo Leon, Mexico

    Science.gov (United States)

    Martinez de Monarrez, Patricia; Korniejczuk, Victor

    2013-01-01

    The purpose of this research was to find the relation-ship between the predominant learning styles among university online students and their attitude toward online education. Data were collected from 385 students enrolled in undergraduate and graduate programs from four universities in the state of Nuevo Leon, Mexico. Significant effects of…

  9. LCA of road infrastructure in Mexico City.

    NARCIS (Netherlands)

    Rosales Carreon, Jesus

    2007-01-01

    Vehicular traffic is a major problem in metropolitan areas and Mexico City is no exception. Located in a pollutant-trapping valley, Mexico City (one of the largest cities in the world) is famous for its size, its history, and the warmth of its people. Nev

  10. Assessing biodiversity in Nuevo Leon, Mexico: Are nature reserves the answer?

    Science.gov (United States)

    Cantu, C.; Wright, R.G.; Scott, J.M.; Strand, Espen

    2004-01-01

    The Mexican state of Nuevo Leon, located in the northeastern portion of the country, currently has 26 state and three federal nature reserves covering approximately 4.5% of its land area. These reserves were established for a variety of reasons not necessarily related to conservation purposes. In 2000 in response to a growing concern about the lack of organized conservation reserve planning to protect the important biological and physical features of Mexico, the Mexican Commission for Knowledge and Use of Biodiversity proposed 12 new terrestrial reserves for Nuevo Leon. The new reserves, if established, would increase the proportion of protected lands in the state to almost 24% of the state's land area. We compiled a Geographic Information System (GIS) analysis using digital thematic maps of physical and ecological features to examine how well the existing and proposed reserves incorporated the major biological and physical features of the state. The existing reserves are located primarily in regions with elevations > 1,000-1,500 m, on less productive soils, and are dominated by pine and oak forest cover types. As a result, the state's dominant biotic region - low elevation coastal plain with xeric scrub vegetation - is disproportionately under represented in the current reserve system. The new reserves would expand the protection of biophysical resources throughout the state. However, the inclusion of important resources in the low elevation coastal lands would still be limited.

  11. FUEL CELL BUS DEMONSTRATION IN MEXICO CITY

    Science.gov (United States)

    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...

  12. Chromium Contamination in Leon Valley Mexico: Insights from Chromium Stable Isotopes

    Science.gov (United States)

    Villalobos-Aragon, A.; Ellis, A. S.; Armienta, M. A.; Morton, O.; Johnson, T. M.; Glessner, J. J.

    2008-12-01

    Chromium (Cr) is a contaminant commonly found in surface and groundwater. In nature Cr commonly occurs in two valences: Cr(VI) is highly mobile, toxic and carcinogenic, while Cr(III) is less mobile. Cr was first detected in groundwater in the Leon Valley region (located in central Mexico) in 1975 (Rodriguez and Armienta, 1995). Previous work proposed an anthropogenic origin for a high concentration plume near the industrial Buenavista (BV), while the larger sub ppb plume located near San Juan de Otates (SJO) is assumed to be caused by weathering of the SJO pyroxenite. Cr stable isotopes have been shown to be useful in monitoring reduction and can also be used to infer redox and transport conditions in natural settings and the goals of our research are: 1) use stable isotope values (δ53Cr) to monitor Cr behavior in the Leon Valley, 2) identify sources (industrial vs. weathering of ultramafic rocks). Since 1975, the highly contaminated BV area is showing a decrease in groundwater Cr(VI) concentrations. Our sampling in 2007 show Cr(VI) concentrations decreasing from 0.005mg/l to 121mg/l to 0.002mg/l to 95.1mg/l. However, the Cr waste piles still exit and Cr(VI) concentrations from leachate collection ponds range from 1.2g/l to 6.8g/l. Isotopic values obtained from leaching experiments performed on the waste pile samples show enriched δ53Cr values (0.76‰ to 3.25‰) either indicating varying reduction or that the waste is fractionated during the ore processing. δ53Cr values for groundwater range from 0.33‰ to 0.46‰, indicating minimal reduction and lack of available reducing agents. The lack of variation of isotopic values seen in the groundwater plume is also consistent with the results of previous studies showing insignificant fractionation due to sorption within the plume (Villalobos-Aragon et al., 2008). The unfractionated Cr(VI) in groundwater vs. those of the waste piles, considered the contamination source, suggests that either 1) the Cr in the waste

  13. Lighting the city. First poetic representations of Mexico City

    Directory of Open Access Journals (Sweden)

    Claudia Kerik

    2018-01-01

    Full Text Available The first impressions that caused the changes made in Mexico City in its process of transformation into a modern city were captured by its poets drawing attention to different aspects of life in the capital. While from the popular poetry the record of the entrance of the electricity in the public road was left, from the official poetry was tried to witness the new cosmopolitan status of the Mexico City in the Porfirian era, through the fashion and the customs that were revealed in one of the main streets of the city. Comparing these poems allows us to know the initial strategies of poetic figuration of urban space that will continue to develop along different paths throughout the twentieth century until we reach our days.

  14. Situation Report--Australia, Burundi, Cambodia, Mexico, Montserrat, Nicaragua, Papua & New Guinea, Republic of Vietnam, Sabah, Sarawak, Sierra Leone, Tahiti, Tonga.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    Data relating to population and family planning in fourteen foreign countries are presented in these situation reports. Countries included are Australia, Burundi, Cambodia, Mexico, Montserrat, Nicaragua, Papua and New Guines, Republic of Vietnam, Sabah, Sarawak, Sierra Leone, Tahiti (French Polynesia), and Tonga. Information is provided under two…

  15. HIV/AIDS practice patterns, knowledge, and educational needs among Hispanic clinicians in Texas, USA, and Nuevo Leon, Mexico

    Directory of Open Access Journals (Sweden)

    Martinez J. Louis

    1998-01-01

    Full Text Available Hispanic clinicians in Texas, United States of America, and in the neighboring state of Nuevo Leon, Mexico, were surveyed to determine their educational needs in the area of HIV/AIDS. Two-thirds of the 74 Texan and 22% of the 104 Mexican physicians queried had seen at least one HIV/AIDS patient in the previous year. The majority of the respondents were primary care physicians who: 1 were in private practice; 2 saw more than 1 000 patients per year; 3 had been out of training for more than 10 years; 4 provided some HIV prevention education to patients based on their perceived risk of infection; 5 rated their own knowledge of HIV/AIDS as average but rated their knowledge of treatments for the disease below average; 6 received most of their information about HIV/AIDS from journals rather than formal continuing education programs; 7 thought Hispanic patients had special needs with regard to HIV/AIDS care; and 8 were willing to attend education programs to improve their HIV/AIDS management skills. The greatest barriers to caring for HIV patients were lack of clinical knowledge and fear of infection. These results point to a need for a large-scale training program to improve the HIV/AIDS management skills of Hispanic clinicians in Texas and Nuevo Leon.

  16. Knowledge Attitude And Practice Of Street Food Vendors In Selected Schools Within Bo City Southern Sierra Leone

    Directory of Open Access Journals (Sweden)

    P.T. Lamin-Boima

    2017-12-01

    Full Text Available This paper attempts to investigate the lack of knowledge attitude and practices of street food vendors in Bo the Southern Province of Sierra Leone. A cross sectional study conducted among eighty-seven respondents vendors in forty-four in Bo City. Data was collected using a structured and semi structured questionnaire. The collected data is analysed using a simple descriptive statistics with the help Excel Microsoft ware. A statistical significance was found in relation to knowledge. Attitude towards food safety was negative self-reported practices by Street Food Vendors were statistically significant with low hygiene standards while predisposing factors showed relatively low personal hygiene poor environmental sanitation and low food safety practice. The realize consequences are utmost health risks of consuming street foods as food contamination has caused food borne diseases and outbreaks. It is recommended that standard training be provided for these vendors by the Bo City Council in collaboration with Njala University. It is essential that poor people in a developing country such as Sierra Leone be allowed to earn their livelihood by means of an easy-to-enter business such as street food vending when hygiene standards are sustained.

  17. Persistent Organic Pollutants and Heavy Metal Concentrations in Soil from the Metropolitan Area of Monterrey, Nuevo Leon, Mexico.

    Science.gov (United States)

    Orta-García, Sandra Teresa; Ochoa-Martinez, Angeles Catalina; Carrizalez-Yáñez, Leticia; Varela-Silva, José Antonio; Pérez-Vázquez, Francisco Javier; Pruneda-Álvarez, Lucia Guadalupe; Torres-Dosal, Arturo; Guzmán-Mar, Jorge Luis; Pérez-Maldonado, Iván N

    2016-04-01

    The purpose of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDE), and four heavy metals (arsenic, cadmium, and lead) in outdoor surface soils (50 samples) collected from the metropolitan area of Monterrey in Mexico. Total PBDEs levels ranged from 1.80 to 127 µg/kg, with mean total PBDEs level of 14.2 ± 21.5 µg/kg (geometric mean ± standard deviation). For PCBs, the mean total level in the studied soils was 23.5 ± 20.2 µg/kg (range 4.0-65.5 µg/kg). An important finding in our study was that all soil samples (100%) had detectable levels of the metabolite p,p'-DDE. Moreover, the mean total DDT level (∑p'p-DDT and p'p-DDE) was approximately 132 ± 175 µg/kg. The mean levels for arsenic, cadmium, and lead in soil were 5.30 ± 1.35 (range 1.55-7.85) mg/kg, 2.20 ± 1.20 (range 0.65-6.40) mg/kg, and 455 ± 204 (range 224-1230) mg/kg, respectively. Our study has several limitations, the most notable of which is the small sample of soils evaluated. However, this screening study provided concentration data for the occurrence of POPs and four heavy metals in soil from the metropolitan area of Monterrey, Nuevo Leon, Mexico, and taking into consideration that soil is an important pathway of exposure for people, a biomonitoring program for the surveillance of the general population in the metropolitan area of Monterrey, Nuevo Leon is deemed necessary.

  18. Urban air pollution, study of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, M. [PUE-UNAM (Mexico); Guzman, F. [Inst. Mexicano del Petroleo (Mexico); Navarro, B. [Univ. Autonoma Metropolitana (Mexico)

    1996-12-01

    The Metropolitan Area of Mexico City (MAMC) is an outstanding case of a fast urban development with lagging, and thus insufficient, massive transportation facilities. This has given rise to a distorted transportation system that accounts for most of the air pollution problem of the city and constitutes a drag on economic development. In this paper, we first describe the MAMC geographical conditions, its growth in physical and economic terms, its transportation system, the ensuring air pollution problems together with some of the mitigation actions undertaken. Afterwards the results of a survey of the displacements of individuals within the city and the time spent on these are presented, to then draw some considerations on the negative economic impact it represents. (EG)

  19. A Hazy Day in Mexico City

    Science.gov (United States)

    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 mineral dust

  20. Hurricane-driven floods in Mexico City

    Science.gov (United States)

    Naranjo, M.

    2012-04-01

    Over thousands of years, floods have globally been the main cause of natural disasters. Over the last century, the impact of floods has been increased due to several factors as the rise in human population, settlements in risk prone areas, land use and cover changes and, the intensification of the hydrological cycle. Currently, disaster management must be carried out with the support of multidisciplinary teams that combine hydrologic and hydraulic studies with socio-economic assessments. We provide an example from the metropolitan area of Mexico City. Previously located in an endorheic basin, its current location lies over several lakes that were intensively managed since the 17th century. Although regular floods have been a characteristic of the region, it is since the 17th century that major sewage works were built in order to mitigate the impact of floods on the urban area. Nowadays, the basin has four artificial outlets that drain the urban runoff and wastewater though only one outlet is gravity-based whereas the remaining three need pumping to work properly. Hence, a hypothetical failure in the drainage system during a major storm event could trigger a flood-related catastrophe. The occurrence of such catastrophe could be driven by precipitation systems derived from the incidence of hurricanes along the Gulf of Mexico. This work analyzes the failure of the gates in the sewage system that provoked a substantial urban inundation in the northern part of Mexico City.

  1. Spatial indoor radon distribution in Mexico City

    International Nuclear Information System (INIS)

    Franco-Marina, Francisco; Villalba-Caloca, Jaime; Segovia, Nuria; Tavera, Leticia

    2003-01-01

    We present a spatial analysis of residential radon concentrations in the Mexico City Metropolitan Area, which we intend to use to assign radon exposure in an ongoing case-control study. As part of a probabilistic household survey, carried out between May and June 1999, 501 dwellings were selected for indoor placement of solid state nuclear track detectors (LR 115) in a cup array over a period of approximately 90 days. As part of the sampling design, the city was grid partitioned into nine zones and a sample of dwellings was selected in each zone. All zones were simultaneously surveyed. The stratified sampling design allowed us to obtain radon geometric means, adjusted for household characteristics, week of detector placement and number of days of measurement for these zones. Additionally, adjusted geometric means were estimated for the 100 census tracts surveyed and this information was used to obtain a more detailed spatial distribution of residential radon levels through kriging interpolation and surface contouring. Radon levels depended on the room of placement, the floor level and the ventilation habits but not on building materials. Regarding the city zone, the highest adjusted geometric mean was found in the southwest (136 Bqm -3 ), where 46% of the households had an estimated radon level in excess of 200 Bqm -3 . In the rest of the city, the geometric mean concentration ranged between 41 and 98 Bqm -3 . A more detailed spatial distribution showed that, in general, most of the eastern and middle zones of the city had estimated radon geometric means below 74 Bqm -3 , while the western ones had geometric means above this concentration. Very high geometric means, exceeding 111 Bqm -3 and even reaching 288 Bqm -3 , are estimated for some areas located in the southern and western zones of Mexico City. The obtained spatial distribution shows that the areas with very high estimated residential radon concentrations are close to inactive volcanic mountains. We believe

  2. Macro and Micro-Nutrient Contents of 18 Medicinal Plants used Traditionally to Alleviate Diabetes in Nuevo Leon, Northeast of Mexico

    International Nuclear Information System (INIS)

    Maiti, R.; Rodriguez, H. G.; Kumari, C. A.; Sarkar, N. C.

    2016-01-01

    Although several medicinal plants has been documented to alleviate diabetes in Nuevo Leon, Northeast of Mexico, no systematic study has been undertaken to determine the efficacy of these plant species. The present study was undertaken to determine micronutrients (Cu, Fe and Zn) and macro-nutrients (K, Mg and P), C, N and C/N and to select plants with high macro and micronutrient contents for high efficacy in 18 medicinal plants collected from botanical gardens of Forest Science Faculty, UANL, Mexico used in Nuevo Leon in Northeast of Mexico, at the experimental station of Facultad de Ciencias Forestales, Universidad Autonoma de Nuevo Leon. Following standard protocols, carbon and nitrogen were determined using a CHN analyzer (Perkin Elmer, model 2400). Mineral contents were using the wet digestion technique (Cherney, 2000). The present study indicated the presence of large variation in the contents of several macro and micronutrients among these 18 species of medicinal plants utilized traditionally to control diabetes and other diseases in Nuevo Leon, Mexico. Among these species containing high nitrogen content (%) are Moringa oleifera (6.25), Melia azadirachta (5.85), Marrubium vulgare (4.56) and Phoradendron villosum (4.9). The C/N values ranged from 8 to 30. The species having high C/N were Agave macroculmis (30), Arbutus xalapensis (26) and Rhus virens (22). The species Melia azadirachta, Marrubium vulgare, Buddleja cordata, Tecoma stans, Hedeoma palmeri, Phoradendron villosum, Opuntia ficus-indica, Arbutus xalapensis exhibited large variations in the contents of macro and micronutrients which, could be considered to be used effectively for the control of diabetes. Few species viz. Marrubium vulgare, Buddleja cordata, Tecoma stans, Hedeoma palmeri, Phoradendron villosum, Opuntia ficus-indica and Arbutus xalapensis on the basis of high nutrient content with respect to C, N, C/N, Cu, Fe, Zn, K, P and Mg are selected and recommended to control diabetes. (author)

  3. Analysis of aerosol samples in Mexico City

    International Nuclear Information System (INIS)

    Martinez, T.; Lartigue, J.; Zarazua, P.; Navarrete, M.; Ramirez, A.; Avila, P.

    2000-01-01

    Total solid particles and 9 metals potentially hazardous for health were determined in Mexico City dwellings by gravimetry and X-ray fluorescence techniques, respectively. Monitoring was performed in spring and winter, on districts covering center, northeast, southeast and southwest of the City. Results show that, in general, the average concentration of metallic contaminants have increased with time and, in the particular case of lead it is higher than the indicative WHO maximum level. The total solid particles figures are also above the U.S. norm of 75 μg.m -3 . Results obtained in samples taken in the same dwelling at different seasons show that lead was not present in a measurable concentration all the time. It seems to exist a correlation between the increase in lead and the increase in total solid particles whose distribution pattern in Mexico City follows wind directions. Another relevant correlation seems to exist between lead concentration and the rate of combustion of fuel in the transport system, which varies with the zone and the season. (author)

  4. 75 FR 28555 - Executive Green ICT & Energy Efficiency Trade Mission to Mexico City, Mexico

    Science.gov (United States)

    2010-05-21

    ... Trade Mission to Mexico City, Mexico AGENCY: International Trade Administration, Department of Commerce... Trade Mission to Mexico City from September 27-29, 2010. This Executive led mission will focus on... smart technologies--provide monitoring, supervision and automation capabilities to reach energy...

  5. Determination of radon levels in Mexico City

    International Nuclear Information System (INIS)

    Pena G, P.

    1992-01-01

    The study of the determination of radon levels in the houses room in Mexico City is part of the project Emanometry of the radon. To carry out this study, the passive method was used, which consists of: thin film dosemeter of cellulose nitrate, container of the same one and spark accountant. The method is based on the mensurations of exhibition of the number of marks of alpha track is of the open type and it allows to average the radon activity along several weeks and it presents low concentrations. This study was carried out in 4 periods of exhibition of 3 months each one. (Author)

  6. Metals in aerosols of the Mexico City

    International Nuclear Information System (INIS)

    Reyes L, J.

    1998-01-01

    The general purpose and scope of this work was to have a data base that includes enough information about the heavy metals which are disseminated in the atmospheric air in Mexico City, like it is what refers to its elements, its concentration and its particle size. For this were collected samples through collectors types: of the filters unit and the cascade impactor. Through the PIXE analysis for filters and films it was identified the presence of 20 elements in the majority of samples studied of the four seasons during the years 1993-1994. The metals were classified in two groups: those of natural origin and those of anthropogenic origin. (Author)

  7. Radon levels inside residences in Mexico City

    International Nuclear Information System (INIS)

    Espinosa, G.

    1990-01-01

    Levels of radon were measured during winter and spring seasons inside 55 colonial and modern houses and 30 multi-family apartment buildings representative of middle and upper income families. The modern houses and apartment buildings in the southern section of the city had average radon levels exceeding 150 Bq.m -3 with a maximum single measurement of 458 Bq.m -3 . The colonial houses in the central downtown section had radon levels nearly all averaging below 100 Bq.m -3 . Between the ground and third floor of the apartment buildings, radon levels diminished tenfold, indicating that entry of radon-bearing soil gas was largely responsible for the elevated concentrations of radon. The radon levels in winter exceeded by about 30% the radon levels during spring. The potentially adverse health effects of these radon levels may be exacerbated by the quality of air in Mexico City which is often highly polluted during winter. (author)

  8. Radon levels inside residences in Mexico City

    International Nuclear Information System (INIS)

    Espinoza, G.

    1989-01-01

    Levels of radon were measured during winter and spring seasons inside 55 colonial and modern houses and 30 multifamily apartment buildings representative of middle and upper income families. The modern houses and apartment buildings in the southern section of the city had average radon levels exceeding 150 Bq m -3 with a maximum single measurement of 458 Bq m -3 . The colonial houses in the central downtown section had radon levels nearly all averaging below 100 Bq m -3 . Between the ground and third floor of the apartment buildings, radon levels diminished by tenfold indicating that entry of radon-bearing soil gas was largely responsible for the elevated concentrations of radon. The radon levels in winter exceeded by about 30% the radon levels during spring. The potentially adverse health effects of these radon levels may be exacerbated by the quality of air in Mexico City which during winter is often highly polluted. 7 refs., 2 figs

  9. Ozone's Threat Hits Back Mexico City

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. Teenagers’ access to contraception in Mexico City

    Directory of Open Access Journals (Sweden)

    Sofía Gómez-Inclán

    2017-05-01

    Full Text Available Objective. To study and understand the phenomenon of access to contraceptive methods in Mexican teenages, through the use of the Levesque model, which allows for the observation of both the system and the system and the user´s participation in the access process. Materials and methods. A qualitative study was conducted with focus groups technique in a middle and high school of Mexico City. Results. The perception of ability to access to health care is limited, teenagers do not know the mechanisms of care or supply of contraceptive methods. Prejudices of service providers provoke a negative reaction. The family is a source of information for adolescents to make decisions. Conclusions. The model allowed the assessment of access to contraceptive methods in teenagers. It were identified dif­ferent aspects that act as barriers to access and may inform health care providers about this population in their sexual and reproductive health.

  12. The heat spells of Mexico City

    Directory of Open Access Journals (Sweden)

    Ernesto Jáuregui

    2010-06-01

    Full Text Available The warning of urban air has been documented to increase in intensity and area as cities grow (Oke, 1982. As the cities grow the so called “heat island” tends to increase the risk of more frequent heat waves as well as their impacts (IPCC, 2001. Threshold values to define a heat wave vary geographically. For the case of Mexico City located in a high inland valley in the tropics, values above 30° C (daily maximum observed for three or more consecutive days and 25° C or more as mean temperature have been adopted to define the phenomenon. These events occur at the end of the dry season during March to May when afternoon relative humidity is quite low (∼20% and thus reducing the stress. Maximum temperatute data from the Observatory of the National Meteorological Service were used. Results show that during the second half of the XXth century the frequency of heat waves as defined above has doubled from 6 events/decade to 16/decade in the 1990s with a marked increase in the last third of the last century when population of the city grew from 8.5 to 18.5 million (CONAPO, 2000. During this time the average urban/rural contrast grew considerably from about 6° C to 10° C (Jáuregui, 1986. While these heat waves may be considered as “mild”they receive attention from the media and prompt actions by the population to relieve the heat stress. Application of heat indices based on the human energy balance (PET and PMV result in moderate to strong heat stress during these events. Because climate change is expected to raise nighttime minimum temperatures more than daytime highs (as suggested by the IPCC, 2001 urban heat islands and their related heat waves are likely to be a significant health concern in days to come in large urban centers especially in the developing countries.

  13. Mexico into the globalization: Nuevo Leon, the safe border for international trade program

    Directory of Open Access Journals (Sweden)

    Barragan, J.

    2006-07-01

    Full Text Available The presentation of this research paper in the 10th annual Conference of the Western Hemispheric Development in the University of Texas A&M in Laredo Texas, (April 23-25, 2005 brought a great opportunity to reflect the efforts of a region in the north of Mexico for the world’s peace and security inside the International trade with the gowth factors important for any and all nations. In this investigation the combined efforts of USA and Mexico are shown to protect the International Trade against the acts of terrorism and smuggling of illegal drugs which constantly try to infiltrate their illicit activities, delivering a great damage to companies that carry out activities of international trade. Relevant conclusions are presented at the end of the paper.

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

    Science.gov (United States)

    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.

  15. Establishing a Water Resources Resilience Baseline for Mexico City

    Science.gov (United States)

    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.

  16. Systemic Competitiveness of SMEs in Mexico City, Mexico

    Directory of Open Access Journals (Sweden)

    Maria Luisa Saavedra García

    2015-07-01

    Full Text Available The objective of this work was to apply the model of systemic competitiveness, SMEs in Mexico City. Developing four levels of competitiveness: macro level (economic environment, meso level (regional environment, Level Goal (Environment Socioeconomic and micro Level (internal factors. Data collection was done through fieldwork and archival research. The main findings are among the major strengths of the economic environment: high level of gross domestic product, high labor productivity and fiscal autonomy, the main weaknesses: the unions and the unemployment rate; meanwhile stand between foreign investment opportunities between threats and insecurity, corruption and difficulty in business transactions. In the regional setting a positive and 1 perfect relationship between the number of economic units and per capita GDP was found. With regard to socio-cultural factors, presents lower levels of poverty and unemployment to the rest of the country. Finally, at the micro level, the competitiveness of SMEs is in direct relation to the size of the company and the industry sector shows higher competitiveness trade and services sectors.

  17. Taking control of air pollution in Mexico city | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Six years later, that air earned Mexico the reputation of “the most dangerous city in the world for children” — a reputation Mexico has been working hard to improve. ... A transdisciplinary research team assessed a range of health benefits and “savings,” including people's willingness to pay for better health and a potentially ...

  18. Light Absorbing Aerosols in Mexico City

    Science.gov (United States)

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

    2008-12-01

    The direct effects of aerosol radiative forcing has been identified by the IPCC as a major uncertainty in climate modeling. The DOE Megacity Aerosol Experiment-Mexico City (MAX-Mex), as part of the MILAGRO study in March of 2006, was undertaken to reduce these uncertainties by characterization of the optical, chemical, and physical properties of atmospheric aerosols emitted from this megacity environment. Aerosol samples collected during this study using quartz filters were characterized in the uv-visible-infrared by using surface spectroscopic techniques. These included the use of an integrating sphere approach combined with the use of Kubelka-Munk theory to obtain aerosol absorption spectra. In past work black carbon has been assumed to be the only major absorbing species in atmospheric aerosols with an broad band spectral profile that follows a simple inverse wavelength dependence. Recent work has also identified a number of other absorbing species that can also add to the overall aerosol absorption. These include primary organics from biomass and trash burning and secondary organic aerosols including nitrated PAHs and humic-like substances, or HULIS. By using surface diffuse reflection spectroscopy we have also obtained spectra in the infrared that indicate significant IR absorption in the atmospheric window-region. These data will be presented and compared to spectra of model compounds that allow for evaluation of the potential importance of these species in adding strength to the direct radiative forcing of atmospheric aerosols. This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64327 as part of the Atmospheric Science Program.

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

    Science.gov (United States)

    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 obesity in Mexico City adolescents, increases the risk of premature development of coronary atherosclerosis and diabetes mellitus in this population.

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

    Science.gov (United States)

    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.

  1. 76 FR 58772 - Safety & Security Trade Mission; Mexico City and Monterrey, Mexico

    Science.gov (United States)

    2011-09-22

    ... DEPARTMENT OF COMMERCE International Trade Administration Safety & Security Trade Mission; Mexico... Commercial Service (CS) is organizing an executive-led Safety and Security trade mission to Mexico City and... protect their business investments, specifically in terms of safety and security of personnel, physical...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  4. Emissions from forest fires near Mexico City

    Directory of Open Access Journals (Sweden)

    R. J. Yokelson

    2007-11-01

    Full Text Available 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 ~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 (~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 MC-area (~98–100 W and 19–20 N. Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.0115 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 ~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.

  5. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

    Science.gov (United States)

    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

  6. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City.

    Science.gov (United States)

    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

  7. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae, in Mexico City

    Directory of Open Access Journals (Sweden)

    Diaz-Perez Alfonso

    2011-05-01

    Full Text Available Abstract 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

  8. City building from the social organizations in eastern periphery of Mexico City

    Directory of Open Access Journals (Sweden)

    Luisa Fernanda RODRÍGUEZ CORTÉS

    2016-12-01

    Full Text Available The development of Mexico City has led to a social and political space marked by the strong presence of social organizations which are connected with clientelistic forms of exchange. This article explores these interwoven relationships from the study of two social organizations that develop in the east of the city. It is argued that social organizations have adapted to social changes of the last twenty years, but remain as central actor into the political relationships, as well as in the configuration of social space in the eastern periphery of Mexico City.

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

    Science.gov (United States)

    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…

  10. Biodiesel from waste cooking oil in Mexico City.

    Science.gov (United States)

    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.

  11. Family Structure and Female Labour Supply in Mexico City

    NARCIS (Netherlands)

    Gong, X.; van Soest, A.H.O.

    1997-01-01

    This paper investigates labour supply of the wives of the heads of households in Mexico City, with a focus on the impact of family structure. A static neoclassical structural model is used. We assume that each woman chooses her labour supply and corresponding income so that her utility is maximized,

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

    Science.gov (United States)

    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 (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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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%).

  16. First Detection of the Kdr Mutation T929I in Head Lice (Phthiraptera: Pediculidae) in Schoolchildren of the Metropolitan Area of Nuevo Leon and Yucatan, Mexico.

    Science.gov (United States)

    Ponce-Garcia, Gustavo; Villanueva-Segura, Karina; Trujillo-Rodriguez, Gerardo; Rodriguez-Sanchez, Iram P; Lopez-Monroy, Beatriz; Flores, Adriana E

    2017-07-01

    The head louse Pediculus humanus capitis (De Geer) is a hematophagous ectoparasite that inhabits the human scalp. Infestations by this insect are commonly known as pediculosis, which is more common in younger groups. These infestations are asymptomatic; however, skin irritation from scratching occasionally may cause secondary bacterial infections. In recent years, the prevalence of pediculosis has increased in children; this increase has been attributed to louse resistance to the insecticides used as a control measure for infestation. The aim of the present study was to determine the presence and frequency of the knockdown resistance mutation (kdr) T929I in 468 head lice collected from 32 elementary schools in the metropolitan area of Nuevo Leon (24) and Yucatan (8), Mexico. This is the first report of a knockdown resistance (kdr) mechanism in head lice from Mexico. The T929I mutation was present in all of the sampled schools, with variability observed in its allelic and genotypic frequencies. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Energy Technology Data Exchange (ETDEWEB)

    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`s 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.

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

    Science.gov (United States)

    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.

  19. Orthopoxvirus antibodies in grey squirrels (Sciurus aureogaster) in Mexico City, Mexico.

    Science.gov (United States)

    Martínez-Duque, Paola; Avila-Flores, Rafael; Emerson, Ginny L; Carroll, Darin S; Suzán, Gerardo; Gallardo-Romero, Nadia F

    2014-07-01

    Serum from Mexican grey squirrels (Sciurus aureogaster) from Mexico City reacted to Orthopoxvirus by enzyme-linked immunosorbent assay. Real-time PCR based on oral swabs and scabs did not detect viral DNA. Antibody prevalence was 30% (n=366), providing the first evidence of Orthopoxvirus antibodies in Mexican wild rodents.

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

    Directory of Open Access Journals (Sweden)

    Bekker-Méndez Vilma

    2011-08-01

    Full Text Available Abstract 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

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

    Science.gov (United States)

    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

    Science.gov (United States)

    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. Levels of coverage and accessibility of infrastructure services of drinking water and health in Nuevo Leon, Mexico

    Directory of Open Access Journals (Sweden)

    Alvarado Lagunas, Elias

    2016-03-01

    Full Text Available Objective. Analyze the distribution infrastructure potable water and health in the state of Nuevo Leon. Materials and methods. To this end, the territorial distribution of the company is analyzed using a geographic information system (GIS in order to demonstrate the existing territorial gap in the formulation of public policy in the hydraulic and health sectors. Results. We show that municipalities with greater social marginalization (no running water or access to health services tend to have the worst health outcomes. Conclusion. It is located in Nuevo Leon there is an unequal distribution of material and human resources in the drinking water and health, as there is a high concentration of these resources in the metropolitan area and the consequent neglect of the municipalities of the periphery. Objetivo. Analizar la distribución de la infraestructura de los sistemas de agua potable y de salud en el estado de Nuevo León. Materiales y métodos. Para tal fin, se analiza la distribución territorial de la entidad mediante un sistema de información geográfica (SIG con el objeto de demostrar la carencia territorial existente en la formulación de las políticas públicas en los sectores hidráulico y de la salud. Resultados. Se demuestra que los municipios con mayor marginación social (sin agua potable ni acceso a servicios de salud tienden a presentar los peores resultados sanitarios. Conclusión. Se encuentra que en Nuevo León existe una distribución desigual de los recursos materiales y humanos en los sistemas de agua potable y de salud, ya que existe una alta concentración de estos recursos en el área metropolitana y el consecuente descuido de los municipios de la periferia.

  4. Water investment in Mexico City: contradictory elements preventing investment efficiency

    OpenAIRE

    M. J. Marquez-Dorantes

    2012-01-01

    The complex connections between environmental and socio-economic variables in the water sector system involve not only ecological changes such as climate change but also a need for changes in socio-economic arenas to reduce the impacts of climate change. It is necessary not only to acknowledge the elements of change but also to understand the constraints preventing change in specific cases. The challenges faced by the water sector in Mexico City, as the world's second largest urban agglomerat...

  5. Housing prices and submarkets in Mexico City: a hedonic assessment

    OpenAIRE

    Jaime Sobrino

    2014-01-01

    The objective of this paper is to explore the role of some quantitative variables in explaining housing prices, and how these variables can be used for the spatial delimitation of housing submarkets. The methodological strategy incorporates issues from the spatial economic theory, and an econometric model of hedonic prices to analyze the main characteristics of housing demand in Mexico City. Housing submarkets are delimited by using a statistical multivariate tool, two-step, log likelihood cl...

  6. The influence of aerosols on photochemical smog in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Castro, T.; Mar, B. [UNAM, Mexico, Centro de Ciencias de la Atmosfera (Mexico); Madronich, S.; Rivale, S. [National Center for Atmospheric Research, Boulder, CO (United States); Muhlia, A. [UNAM, Mexico, Inst. de Geofysica (Mexico)

    2001-04-01

    Aerosols in the Mexico City atmosphere can have a non-negligible effect on the ultraviolet radiation field and hence on the formation of photochemical smog. We used estimates of aerosol optical depths from sun photometer observations in a detailed radiative transfer model, to calculate photolysis rate coefficients (J{sub NO2}) for the key reaction NO{sub 2}+h{nu}{yields}NO+O ({lambda}<430nm). The calculated values are in good agreement with previously published measurements of J{sub NO2} at two sites in Mexico City: Palacio de Mineria (19 degrees 25'59''N, 99 degrees 07'58''W, 2233masl), and IMP (19 degrees 28'48''N, 99 degrees 11'07''W, 2277masl) and in Tres Marias, a town near Mexico City (19 degrees 03'N, 99 degrees 14'W, 2810masl). In particular, the model reproduces very well the contrast between the two urban sites and the evidently much cleaner Tres Marias site. For the measurement days, reductions in surface J{sub NO2} by 10-30% could be attributed to the presence of aerosols, with considerable uncertainty due largely to lack of detailed data on aerosol optical properties at ultraviolet wavelengths (esp. the single scattering albedo). The potential impact of such large reductions in photolysis rates on surface ozone concentrations is illustrated with a simple zero-dimensional photochemical model. (Author)

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

    Science.gov (United States)

    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 (

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

    Science.gov (United States)

    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

  9. Decriminalization of abortion in Mexico City: The effects on women's reproductive rights

    OpenAIRE

    Becker, Davida

    2013-01-01

    In April 2007, the Mexico City 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 over 89,000 legal abortions have been performed. By contrast, abortion has continued to be restricted across the Mexican states (each state makes their own abortion laws) a...

  10. Educational Inequality in Nuevo Leon and Oaxaca, Mexico, 2008 and 2010: The Basis of an Uncertain Future for These Societies

    Science.gov (United States)

    Pierdant R., Alberto I.; Rodríguez Franco, Jesús; Narro R., Ana Elena

    2017-01-01

    Education in society especially in Mexico, seems to be a powerful instrument of intergenerational social mobility to produce individuals with "capabilities and functions" allowing them to obtain a greater well-being. "Education as schooling," in the first instance, improves the individuals living conditions, since this is a…

  11. Adolescent alcohol use and alcohol use disorders in Mexico City.

    Science.gov (United States)

    Benjet, Corina; Borges, Guilherme; Méndez, Enrique; Casanova, Leticia; Medina-Mora, María Elena

    2014-03-01

    To estimate the prevalence, sex, age distribution, and socio-demographic correlates of any alcohol use, consumption patterns, and any alcohol use disorder in a representative sample of Mexican adolescents. 3005 youth (52.1% female) aged 12-17 from a stratified multistage area probability sample were representative of adolescents residing in the Mexico City Metropolitan Area. Alcohol use and disorder and their socio-demographic correlates were evaluated with the World Mental Health adolescent version of the Composite International Diagnostic Interview. Data were post-stratified to the total Mexico City adolescent population. 59% has used alcohol, this proportion increasing significantly with age. By age 17, 82.5% has used alcohol. Consumption patterns are mostly of low/moderate quantity or infrequent high quantity. Lifetime DSM-IV alcohol use disorder criteria are met by 3.8%, reaching 8.1% for 16-17 years-olds. While males have greater frequency and quantity of drinking, there are no gender differences for alcohol use disorders. Non-school attending youth have twice the odds of a lifetime (OR=2.0, 95% CI=1.13-3.53) and 12-month disorder (OR=2.1, 95% CI=1.10-4.15). Low parental monitoring is associated with 1.72 times the odds of a lifetime disorder (95% CI=1.10-2.68). Over a third of 12 year-olds had ever drunk an alcoholic beverage in their lifetime suggesting that the prevention of alcohol use and disorders must begin in late childhood. Initiatives to foment parental monitoring and to prevent, identify, and treat alcohol use problems in non-school attending youth in particular should be a priority for the wellbeing of Mexico City adolescents. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  13. Coupled seismic modes and earthquake hazard in Mexico City

    Science.gov (United States)

    Lomnitz, C.

    2007-05-01

    Wave-to-wave coupling can arise when an acoustic pulse selects a Rayleigh mode of the same speed and both travel together swapping energy across an interface. A similar effect may cause severe damage at distances of several hundred kilometers when an Lg wavetrain incides upon a soft remote sedimentary waveguide, as in Mexico City. Energy at a single dominant frequency is then trapped in the waveguide. When the input power exceeds the damping losses, the trapped mode reverberates in the layer for up to five minutes, causing severe resonant damage to structures.

  14. Gamma radiation and radon levels in Mexico City dwellings

    International Nuclear Information System (INIS)

    Martinez, T.; Cabrera, L.; Navarrete, M.; Garcia, J.J.; Ramirez, A.; Martinez, U.

    1995-01-01

    Gamma exposure rate and radon levels were measured in 75 single-family dwellings in Mexico City in order to correlate them with local environment. Radon monitoring was performed both indoors and outdoors using a continuous working level monitor for short-lived radon decay products; the gamma exposure rate was measured using CaSO 4 : Dy + PTFE. The results obtained show a log-normal distribution. The mean indoor radon concentration is lower than 45 Bq/m 3 and the mean indoor gamma exposure rate was 11.29 μR/h. (author) 12 refs.; 10 figs.; 5 tabs

  15. Knowledge of ischemic stroke among a Mexico City population.

    Science.gov (United States)

    Góngora-Rivera, Fernando; Gutiérrez-Jiménez, Eugenio; Zenteno, Marco Antonio

    2009-01-01

    Knowledge of risk factors (RF) and warning signs of stroke by the general population is fundamental to implement efficient preventive measures and provide timely treatment. The objective of this study was to assess this knowledge in a sample population of Mexico City. Personal interview was conducted in a multifamily building complex in Mexico City. The questionnaire included sociodemographic and comorbidity factors. Knowledge was determinated according to the number of correct answers. Chi-square and Wilcoxon rank tests were performed and significant variables were included in a multivariate logistic regression model using level of knowledge as the dependent variable. A total of 330 subjects were interviewed. Of the respondents, 66.7% named one RF associated with ischemic stroke, whereas only 12.1% identified 3 or more; one warning sign was identified by 36.7% and only 2.1% identified 3 or more. The factors associated with knowledge of RF were history of hypertension, educational level, and family history of ischemic stroke. Educational level and a family history of stroke were also associated with knowledge of warning signs. A Family history of ischemic stroke was the most important way to receive information about RF and warning signs of ischemic stroke. The study shows the need for informing the public about prevention and early detection of ischemic stroke.

  16. Senate votes to fund UNFPA, reverse Mexico City policy.

    Science.gov (United States)

    1991-08-09

    The US Senate has voted to restore funding to UNFPA and reverse the administration's Mexico City policy by passing a fiscal 1992-93 foreign aid authorization bill containing both provisions. The UNFPA issue has also been linked to the debate of the most favored nations (MFN) bill for China. Sen. Paul Simon introduced a floor amendment stipulating that none of the US aid could be used for UNFPA's China program; if this occurred, the full US contribution would have to be refunded. The Bush administration policy of boycotting UNFPA because of China's population policy is holding UNFPA hostage. Sens. Barbara Mikulski and Tim Wirth added another condition to the China MFN bill that would force the president to certify that the Chinese government does not support coercive abortion. The president has threatened to veto any bill that puts conditions on China's MFN status. However, evidence suggests that even Bush is uncomfortable with his own reasoning being used against him. He is condemning UNFPA for having the same policy toward China that he does. Both bills call for $20 million for UNFPA for fiscal 1992 and reverse the Mexico City policy. Both bills raise the ceiling for fiscal 1992 to $300 million for population aid. There would have to be some debate to reconcile the fiscal 1993 ceiling of $350 million passed by the House and the $300 million passed by the Senate. The president has threatened to veto both bills because of the family planning provisions.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 (organic aerosols are also very small. © 2012 American Chemical Society

  19. Upscaling pollutant dispersion in the Mexico City Metropolitan Area

    Science.gov (United States)

    Valdés-Parada, Francisco J.; Varela, Juan R.; Alvarez-Ramirez, José

    2012-02-01

    Pollutant emission is an important problem in megacities such as Mexico City, imposing serious threats to human health and economic activity. Public policies oriented to deal with pollutant management ought to be based upon a close understanding of the transport mechanisms involved in the commonly complex network of streets and buildings. Modeling and simulation tools have proved to be useful for understanding field measurements and developing efficient monitoring strategies. The aim of this work is to provide estimations of the (longitudinal and transverse) dispersion coefficients in upscaled models for pollutant transport in the Mexico City Metropolitan Area (MCMA). To this end, we use the method of volume averaging, which allows calculation of the dispersion coefficients by solving the associated closure problems in some representative regions of the MCMA. The results show that local geometry has an important effect upon contaminant dispersion, especially in the direction that is transverse to the pressure gradient. This suggests that, although winds can remove an important amount of atmospheric contaminants, high transversal dispersion can help in a fast spreading of contaminants within the street network.

  20. [Bullying of emos in Mexico City: an ethnographic analysis].

    Science.gov (United States)

    Hernández-Rosete, Daniel

    2017-12-18

    The article describes the beliefs that have fueled violence by various groups against male and female "emos" in Mexico City. This was an ethnographic study from 2012 to 2015 based on 24 in-depth interviews with young students enrolled in public universities in Mexico City in 2008. The study focused primarily on emos (10), but also included young people that described themselves as punks (6), darks (5), and rockers (3). The findings suggest that bullying of emos is deeply rooted in gender beliefs, particularly hegemonic notions of masculinity. The study highlights the fact that bullying is perpetrated not only by other youth, but also occurs in the family and school settings, where the violence is taken for granted as a legitimate construct associated with the idea of discipline in school. The strategies used by these young people to resist bullying suggest reflexive attitudes towards their historical, scholastic, and family contexts. They are able to reaffirm their collective demand for the right to education and diversity in university classes, but the situation calls for policies to prevent bullying, especially in the university community.

  1. Measurements of indoor radon and radon progeny in Mexico City

    International Nuclear Information System (INIS)

    Cheng, Y.S.; Rodriguez, G.P.

    1996-01-01

    Indoor radon has been a public concern associated with increased lung cancer risks. Radon decay products interact with indoor aerosols to form progeny with different size distributions, which may influence the lung dosimetry when the progeny are inhaled. Air pollution in Mexico City is a serious problems with high particulate concentrations, but there are few reports of indoor radon measurement. The purposes of this study were to measure the aerosol concentration, radon concentration, and radon activity size distribution in the living area of three houses in Mexico City. The radon concentration was monitored by a RGM-3 radon gas monitor (Eberline, Inc., Santa Fe, NM). A graded diffusion battery was used to determine the progeny concentration and activity size distribution. The concentration and size distribution of the indoor aerosols were monitored by a quartz, crystal microbalance cascade impactor. Our measurements showed high concentrations of indoor aerosols (20-180 gg m -3 ). However, the radon concentrations-were low ( -1 ), but showed a clear diurnal pattern with peak concentrations from 2-10 AM. The activity size distributions of radon progeny were trimodal, with peaks of 0.6 nm, 4-5 nm, and 100 rim. Most activities were associated with large particle sizes. Our results indicated that indoor radon concentration was not high, due in part to a relatively high air exchange with outdoor air. The high aerosol concentration may also play an important part in the activity size distribution of radon progeny

  2. Radon and thoron levels in Mexico City dwellings

    International Nuclear Information System (INIS)

    Martinez, Trinidad; Cabrera, L.; Olivares, Jose Luis

    2001-01-01

    This paper presents the results obtained for the short-lived radon decay products concentration measured with a continuous working level monitor in 1992-1994. Arithmetic and geometric means were 2.24 and 2.1 mWL respectively. Annual radon gas concentrations were measured with passive electret system (type E-PERM ) in 154 single-family dwellings, in normal occupancy conditions (open house condition) in the Metropolitan Zone of Mexico City during 1994-1995 monitoring campaign in the Metropolitan Zone of Mexico City. The results show the general log-normal distribution of integrated indoor radon concentration with an annual indoor mean of 3.8 p Ci L -1 . The seasonal variation shows the minimum mean values in the summer season which are 39% lower than that in autumn. Equilibrium factors (F) were measured in all seasons along year using a continuous working level monitor for short-lived radon decay products and a H-chamber loaded with a short term electret (HSTB-EPERM) for radon gas. The obtained total mean equilibrium factor is F=0.4±0.17. Thoron levels were measured with the configuration SSTB-EPERM and results are discussed. (author)

  3. Crude and Adjusted Prevalence of Sleep Complaints in Mexico City.

    Science.gov (United States)

    Jiménez-Genchi, Alejandro; Caraveo-Anduaga, Jorge

    2017-01-01

    To estimate the crude prevalence rates of several sleep complaints and the prevalence for each one adjusted for the coexistence of symptoms in other sleep domains in a representative sample of adult individuals from Mexico City. A probabilistic sample of 1933 adult individuals living in Mexico City was surveyed using fourteen questions of the Sleep Disorders Questionnaire to assess sleep-related symptoms and sleep complaints. Estimates of crude prevalence rates for each sleep disturbance and adjusted for a score ≥ the 80th. percentile in the questionnaire were calculated. The following prevalence rates were found: insomnia 39.7%; excessive diurnal sleepiness (EDS) 20.9%; obstructive sleep apnea syndrome (EDS plus snoring) 7.7%; habitual snoring 9.9%; restless legs syndrome (RLS) 4.4%; narcolepsy 0.9%; sleep paralysis (SP) 13.2%; and hypnotic use 1.2%. When prevalence rates were calculated accounting for symptoms in other sleep domains, notable reductions were observed in complaints of insomnia (17.3%), EDS (10.3%), and SP (8.7%), while minor decreases were observed for complaints of snoring (7.4%), OSAS (5%), and RLS (3.8%); narcolepsy prevalence practically did not change (0.9%). Sleep complaints are highly prevalent in Mexican adult population. More than a half of the individuals with a given sleep disturbance have a global sleep deterioration associated to psychosocial and health impairments.

  4. Crude and Adjusted Prevalence of Sleep Complaints in Mexico City

    Directory of Open Access Journals (Sweden)

    Alejandro Jiménez-Genchi

    Full Text Available OBJECTIVE: To estimate the crude prevalence rates of several sleep complaints and the prevalence for each one adjusted for the coexistence of symptoms in other sleep domains in a representative sample of adult individuals from Mexico City. METHODS: A probabilistic sample of 1933 adult individuals living in Mexico City was surveyed using fourteen questions of the Sleep Disorders Questionnaire to assess sleep-related symptoms and sleep complaints. Estimates of crude prevalence rates for each sleep disturbance and adjusted for a score ≥ the 80th. percentile in the questionnaire were calculated. RESULTS: The following prevalence rates were found: insomnia 39.7%; excessive diurnal sleepiness (EDS 20.9%; obstructive sleep apnea syndrome (EDS plus snoring 7.7%; habitual snoring 9.9%; restless legs syndrome (RLS 4.4%; narcolepsy 0.9%; sleep paralysis (SP 13.2%; and hypnotic use 1.2%. When prevalence rates were calculated accounting for symptoms in other sleep domains, notable reductions were observed in complaints of insomnia (17.3%, EDS (10.3%, and SP (8.7%, while minor decreases were observed for complaints of snoring (7.4%, OSAS (5%, and RLS (3.8%; narcolepsy prevalence practically did not change (0.9%. CONCLUSIONS: Sleep complaints are highly prevalent in Mexican adult population. More than a half of the individuals with a given sleep disturbance have a global sleep deterioration associated to psychosocial and health impairments.

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

    Science.gov (United States)

    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,...

  6. Qualitative evidence on abortion stigma from Mexico City and five states in Mexico.

    Science.gov (United States)

    Sorhaindo, Annik M; Juárez-Ramírez, Clara; Díaz Olavarrieta, Claudia; Aldaz, Evelyn; Mejía Piñeros, María Consuelo; Garcia, Sandra

    2014-01-01

    Social manifestations of abortion stigma depend upon cultural, legal, and religious context. Abortion stigma in Mexico is under-researched. This study explored the sources, experiences, and consequences of stigma from the perspectives of women who had had an abortion, male partners, and members of the general population in different regional and legal contexts. We explored abortion stigma in Mexico City where abortion is legal in the first trimester and five states-Chihuahua, Chiapas, Jalisco, Oaxaca, and Yucatán-where abortion remains restricted. In each state, we conducted three focus groups-men ages 24-40 years (n = 36), women 25-40 years (n = 37), and young women ages 18-24 years (n = 27)-and four in-depth face-to-face interviews in total; two with women (n = 12) and two with the male partners of women who had had an abortion (n = 12). For 4 of the 12 women, this was their second abortion. This exploratory study suggests that abortion stigma was influenced by norms that placed a high value on motherhood and a conservative Catholic discourse. Some participants in this study described abortion as an "indelible mark" on a woman's identity and "divine punishment" as a consequence. Perspectives encountered in Mexico City often differed from the conservative postures in the states.

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

    Science.gov (United States)

    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

  8. Urban guides: image and space invention in Mexico City

    Directory of Open Access Journals (Sweden)

    Héctor Mendoza Vargas

    2016-03-01

    Full Text Available This article analyzes the urban guides of Mexico City from a wide time-lapse perspective, from the end ofthe eighteenth century to the nineteenth century and up to 1940, in order to detect major themes and the change of urban perception. In foreigner’s guide outlines, from 1792 to 1793, the Cathedral’s central position conferred strength to the maps inserted in such editions. It is worth noting the subliminal role of this document regarding urban perception, social behavior and the maintenance of religious devotion in the capital of New Spain. After Mexico’s independence these guides lacked novelty. During the years between 1842 and 1854, this editorial genre was reactivated in the Mexican capital. In those years the guides were included in an attempt to fulfill the increasing need for information about the city regarding political, judicial, ecclesiastical and military aspects including, as the main novelty, the continuously expansive commercial sector. While guide editions were modified in order to satisfy the consumption and preferences of the nascent urban bourgeoisie, both editors and authors detected novel concerns among readers, not only about commercial life but they also looked for pleasant and ludic experiences in the city.

  9. Metals in aerosols of the Mexico City; Metales en aerosoles de la Ciudad de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Reyes L, J. [Instituto Nacional de Investigaciones Nucleares, Salazar, Estado de Mexico C.P. 52045 (Mexico)

    1998-07-01

    The general purpose and scope of this work was to have a data base that includes enough information about the heavy metals which are disseminated in the atmospheric air in Mexico City, like it is what refers to its elements, its concentration and its particle size. For this were collected samples through collectors types: of the filters unit and the cascade impactor. Through the PIXE analysis for filters and films it was identified the presence of 20 elements in the majority of samples studied of the four seasons during the years 1993-1994. The metals were classified in two groups: those of natural origin and those of anthropogenic origin. (Author)

  10. [Prevalence of Dental Fluorosis and Caries in Mexico City Schoolchildren].

    Science.gov (United States)

    Juárez-López, María Lilia Adriana; Hernández-Guerrero, Juan Carlos; Jiménez-Farfán, Dolores; Ledesma-Montes, Constantino

    2003-01-01

    This study was conducted to determine prevalence and severity of dental fluorosis and dental caries in school-children living in two zones of the Mexico City's East Area. Fluorosis and caries scores were recorded for 1,569 children according to the Dean Community Index, DMFT and DMFS indexes, and the relationship between fluorosis and fluoride sources was investigated. Dental fluorosis was found in 60.42% of children. Dean's Community score was 0.96 (SD-0.58). Quantity of toothpaste employed, toothbrushing frequency, and early initiation of toothbrushing correlated well with fluorosis (p = 0.03). Caries was present in 70.52% of children, DMFT and DMFS scores were 2.64 (SD 2.4) and 3.97 (SD 4.18) respectively. DMFT and DMFS scores were lower in children with mild and moderate fluorosis than in those fluorosis-free children. (p = 0.03).

  11. Raindrop size distributions and storm classification in Mexico City

    Science.gov (United States)

    Amaro-Loza, Alejandra; Pedrozo-Acuña, Adrián; Agustín| Breña-Naranjo, José

    2017-04-01

    Worldwide, the effects of urbanization and land use change have caused alterations to the hydrological response of urban catchments. This observed phenomenon implies high resolution measurements of rainfall patterns. The work provides the first dataset of raindrop size distributions and storm classification, among others, across several locations of Mexico City. Data were derived from a recent established network of laser optical disdrometers (LOD) and retrieving measurements of rainrate, reflectivity, number of drops, drop diameter & velocity, and kinetic energy, at a 1-minute resolution. Moreover, the comparison of hourly rainfall patterns revealed the origin and classification of storms into three types: stratiform, transition and convective, by means of its corresponding reflectivity and rainrate relationship (Z-R). Finally, a set of rainfall statistics was applied to evaluate the performance of the LOD disdrometer and weighing precipitation gauge (WPG) data at different aggregated timescales. It was found that WPG gauge estimates remain below the precipitation amounts measured by the LOD.

  12. Variation in indoor thoron levels in Mexico City dwellings

    International Nuclear Information System (INIS)

    Martinez, T.; Navarrete, M.; Gonzalez, P.; Ramirez, A.

    2004-01-01

    This paper presents the results obtained for thoron concentration in 50 single-family dwellings in normal occupancy conditions (open house conditions), measured by a passive electret system (type E-PERM, SSTB configuration) in a 2001-2002 monitoring survey in the Metropolitan Zone of Mexico City. The results show the general log-normal distribution of integrated indoor thoron concentration with annual arithmetic and geometric means of 82 and 55 Bq m -3 , respectively, with ranges from 8 to 234 Bq m -3 higher than world average of 3 Bq m -3 . The seasonal variation shows the minimum mean values in the summer season that were 35% lower than in autumn. (authors)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Natural hazards and urban policies in Mexico City

    Directory of Open Access Journals (Sweden)

    François Mancebo

    2009-07-01

    Full Text Available L’agglomération de Mexico, à plus de 2 000 mètres d’altitude, adossée à la Sierra Madre et la Cordillère Volcanique est assise sur un site accueillant mais redoutable. Il s’agit d’un des endroits les plus exposés du globe, soumis à une combinaison de risques naturels, de risques technologiques souvent mal maîtrisés dus à des industries lourdes, de nuisances, de cumul des polluants et d’un épuisement des ressources locales utilisables, tout particulièrement les ressources en eau. Après le séisme dévastateur de 1985, les acteurs de l’aménagement de Mexico tentent d’intégrer risques et durabilité dans la définition de nouvelles politiques urbaines. Mais, si les risques sont bien identifiés et des réponses sont données, leur applicabilité est quasi-nulle. Une approche normative et n’incluant pas l’ensemble de l’agglomération, mais utilisant les périphéries pour améliorer la durabilité des centres (sorte de durabilité importée à l’échelle de la métropole explique cette situation. Comme dans le mythe de Sisyphe, acteurs locaux et nationaux tentent de faire remonter la pente au rocher du risque mais ce dernier finit toujours par redescendre ? C’est qu’en réalité le problème n’est pas le rocher. Le problème, c’est la pente, c’est-à-dire le substrat fait de représentations territoriales et d’usages de l’espace qui fondent la société mexicaine, sur laquelle roule le rocher.Mexico City is located at an altitude of over 2 000 metres where it occupies an attractive but hazardous site hemmed in by the Sierra Madre and volcanic mountain ranges.The site is one of the most disaster-prone locations in the world, threatened by a combination of natural hazards, poorly controlled technological hazards created by the city’s heavy industry, pollution – particularly air pollution and diminishing local resources, the most seriously threatened being water. Since the devastating earthquake

  16. Corporative Trends in Urban Distribution of Goods in Mexico City

    International Nuclear Information System (INIS)

    Antun, J.P.

    2016-01-01

    The Logistics processes in urban-metropolitan distribution are constantly changing, both technological support and technical implementation in the processes themselves and in the management of these. It is necessary to monitor the substantive changes outlined in the metropolitan urban-physical distribution of goods, because they contribute to a better competitive position of companies in the market, and also to a better development of city life. It is a professional scientific and technical task that contributes, by its impact on b enchmarking , the improvement of engineering practices in the professional community of executives in logistics and supply chains. Based on three extensive field research (ANTÚN, JP; LOZANO, A; HERNÁNDEZ, R; ALARCÓN, R et al 2007; ANTÚN, JP; LOZANO, A; MAGALLANES, R; ALARCÓN, R; GRANADOS, F 2009, ANTUN JP ALARCON R; 2014) on Logistics Distribution of Goods in Mexico City, this article presents and discusses major corporate trends on a set of key logistics processes, and bring examples from Case Studies. (Author)

  17. Volatile organic compounds in the atmosphere of Mexico City

    Science.gov (United States)

    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.

  18. Designing Freshwater Resilience for the Mexico City Metropolitan Area

    Science.gov (United States)

    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

  19. Shifting corporate geographies in global cities of the South: Mexico City and Johannesburg as case studie

    Directory of Open Access Journals (Sweden)

    Parnreiter, Christof

    2013-09-01

    Full Text Available Global city research links the expansion of advanced producer services in major cities to the internationalisation of real estate markets as well as to the spread of (mainly high-rise office complexes. This research, however, has based its findings mainly on cases of the Global North. This paper examines, based on Grant and Nijman’s (2002 suggestion that the “internal spatial organisation of gateway cities in the less-developed world” reflects “the city’s role in the global political economy”, which patterns occur in two metropoles of the Global South. In addition to this, the analysis focuses especially on the driving forces behind the changes in corporate geographies. The analysis is placed in Mexico City and Johannesburg and based on real estate market data (offices as well as background documents on urban development. The outcome shows that in these cities, local transformation processes of the real estate market and office space location are indeed considerably shaped by global market dynamics. However, the findings also indicate that there is no clear scale dependence of the territorial form. In order to comprehensively understand the changes in the corporate geographies therefore, it is necessary to direct more attention to local and national dynamics. The restructuring of the built environment in both cities can only be grasped fully by considering the particular role of local and national governments. This additional entry point to an understanding of shifting corporate geographies helps to put recent dynamics of global capitalism and politics of urban neoliberalism in perspective.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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,…

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Emissions inventory for the Mexico City Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa, V.H.P.; Renteria, J.S. [Secretaria de Medio Ambiente, Col. Tiacopac San Angel (Mexico); Hernandez, C.G. [Departamento del Distrito Federal, Col. Centro (Mexico)] [and others

    1996-12-31

    The emissions inventory bears a broad relationship to the energy balance, reflecting the dependence of the emissions with reference to the use of energy. Actually the consumption of gasoline and diesel fuel in the transport sector represents collectively, the greatest comparative expense of energy and the major contributor of the ozone precursor pollutants HC, NO{sub x} and CO, relative to the total volume of emissions in the Mexico City Metropolitan Area (MCMA). Also, the industrial sector introduces significant emissions of SO{sub 2} and NO{sub x} due to its energy consumption of fuel oils and natural gas. In contrast, the great majority of suspended particulate in the MCMA emanate from degradation processes of surface soil along the periphery of the urban zone. To the federal and local authorities charged with the design of strategies for prevention and control of atmospheric pollution, the emissions inventory is a strategic tool that reflects the relative intensity of the various emitters to the load capacity of the atmosphere. A comprehensive inventory was compiled for 1995, categorizing the emissions generated by four sectors: industry, services, transport and surface soils and vegetation, considering the following pollutants: TSP, SO{sub 2}, NO{sub x}, HC and CO. The combined pollutant emissions are 4,009,628 tons/year of which 3% are generated by the industry, 10% by the services sector, 75% by the transport sector, and 12% by surface soils and vegetation.

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

    Science.gov (United States)

    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 (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.

  7. Surface albedo measurements in Mexico City metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Castro, T; Mar, B; Longoria, R; Ruiz Suarez, L. G [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico); Morales, L [Instituto de Geografia, UNAM, Mexico, D.F. (Mexico)

    2001-04-01

    Optical and thermal properties of soils are important input data for the meteorological and photochemical modules of air quality models. As development of these models increase on spatial resolution good albedo data become more important. In this paper measurements of surface albedo of UV (295-385 nm) and visible (450-550 nm) radiation are reported for different urban and rural surfaces in the vicinity of Mexico City. It was found for the downtown zone and average albedo value of 0.05 which is in very good agreement with reported values for urban surfaces. Our albedo values measured in UV region for grey cement and green grass are of 0.10 and 0.009, respectively, and quite similar to those found at the literature of 0.11 and 0.008 for those type of surfaces. [Spanish] Las propiedades opticas y termicas de suelos son datos importantes para los modulos meteorologicos y fotoquimicos de los modelos de calidad del aire. Conforme aumenta la resolucion espacial del modelo se vuelve mas importante contar con buenos datos de albedo. En este articulo se presentan mediciones de albedo superficial de radiacion Ultravioleta (295-385 nm) y visible (450-550 nm) para diferentes superficies urbanas. Los valores medidos de albedo en la region UV para cemento gris y pasto verde son de 0.10 y 0.009, respectivamente, y son muy similares a los reportados en la literatura, 0.11 y 0.008 para este tipo de superficies.

  8. Service use among Mexico City adolescents with suicidality.

    Science.gov (United States)

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

    2010-01-01

    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). 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. 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. 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. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, H.B.; Jardon, R.T.; Echeverria, R.S. [Centro de la Atmosfera (Mexico). Seccion de Contaminacion Ambiental

    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 a 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.

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

    Science.gov (United States)

    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.

  11. Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2009-03-01

    Full Text Available Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1μm diameter, semi-volatile partitioning requires 15–30 min to equilibrate; longer time is typically required during the night and early morning hours. Aerosol and gas-phase speciation always exhibits substantial temporal variability, so that aerosol composition measurements (bulk or size-resolved obtained over large integration periods are not reflective of its true state. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as "equivalent sodium" (rather than explicitly in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.

  12. Service use among Mexico City adolescents with suicidality

    Science.gov (United States)

    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

  13. Photochemistry in the Atmospheres of Denver and Mexico City

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  15. Surface energy balance measurements in the Mexico City: a review

    Energy Technology Data Exchange (ETDEWEB)

    Tejeda Martinez, A. [Universidad Veracruzana, Xalapa, Veracruz (Mexico); Jauregui Ostos, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, UNAM, Mexico, D.F. (Mexico)

    2005-01-01

    During the last decade of the 20th Century, diverse campaigns for measuring the atmospheric energy balance were performed in downtown Mexico City (School of Mines and Preparatory School No. 7), in the southern suburbs (University Reserve) and in the surrounding rural areas (Plan Texcoco), in addition to a campaign carried out in 1985 in the Tacubaya district, a suburban western peripheral site. The objective was to obtain data for a better understanding of the climatic alterations due to urbanization, particularly to describe the role that the modification of the natural ground cover has played as a result of paving and the construction of urban canyons. In this paper, a review of these campaigns is presented. Energy partitioning in some areas (Tacubaya and Preparatory School No.7) is similar to that observed in urban centers of middle latitudes, whereas the major contrast was observed between Texcoco, with maximum energy consumption through evaporation, and School of Mines, where the latent heat is as low as in a desert. From the values of the correlations among the different components of energy balance, it may be possible to attempt the modeling of the diverse components of energy balance by means of regression equations starting from the net radiation. Those same coefficients distinguish the type of environment: urban, suburban or rural. [Spanish] Las primeras mediciones de balance energetico en la Ciudad de Mexico se realizaron en 1985 en un suburbio al poniente de la ciudad (el observatorio de Tacubaya). Ya en la decada de los anos noventa del siglo XX, dichas observaciones se multiplicaron tanto en el centro historico (antigua Escuela de Minas y en el edificio de la Preparatoria No. 7), como en otros sitios al sur (en terrenos de Ciudad Universitaria) y en la periferia rural (Plan Texcoco). El proposito de estas mediciones ha sido tener un mejor entendimiento de las alteraciones climaticas debidas a la urbanizacion. En este trabajo se presenta una revision

  16. Mexico City air quality: Progress of an international collaborative project to define air quality management options

    International Nuclear Information System (INIS)

    Streit, G.E.

    1992-01-01

    Mexico City, faces a severe air pollution problem due to a combination of circumstances. The city is in a high mountain basin at a subtropical latitude. The basin setting inhibits dispersion of pollution and contributes to frequent wintertime thermal inversions which further trap pollutants near the surface. The elevation and latitude combine to provide plentiful sunshine which, in comparison to more northern latitudes, is enhanced in the UV radiation which drives atmospheric photochemistry to produce secondary pollutants such as ozone. The Area Metropolitana de la Ciudad de Mexico AMCW is defined to include the 16 delegations of the Federal District (D.F.) and 17 highly urbanized municipalities in the State of Mexico which border the D.F. The 1990 census (XI Censo General de Poblacion y Vivienda de 1990) records that slightly over 15 million people live in the AMCM. There are numerous other nearby communities which are in the airshed region of Mexico City, but which are not included in the definition and population of the AMCM. The Mexico City Air Quality Research Initiative is one project that is examining the complex relationship between air pollution, economic growth, societal values, and air quality management policies. The project utilizes a systems approach including computer modeling, comprehensive measurement studies of Mexico City's air pollutants, environmental chemical reaction studies and socioeconomic analysis. Los Alamos National Laboratory (USA) and the Mexican Petroleum Institute are the designated lead institutions

  17. Diabetes and Cause-Specific Mortality in Mexico City

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  20. Community Policing in Latin America: Lessons from Mexico City

    Directory of Open Access Journals (Sweden)

    Markus-Michael Müller

    2010-04-01

    Full Text Available Community policing programmes are widely perceived and promoted as an important solution for the pressing problems of insecurity in contemporary Latin American cities, and for improving citizen-police relationships. By drawing on the results of empirical fieldwork conducted in Mexico City, the article presents a critical analysis of the local community policing effort. The article demonstrates that this policing effort is overly determined by a local context, characterized by clientelism, political factionalism and police corruption, which therefore renders its contribution to a sustainable improvement of local accountability and police legitimacy unlikely. Against this background the article calls for more empirical studies on this topic and a greater sensitivity for the embeddedness of policing programmes within a wider political context.    Resumen: Colaboración ciudadana en América Latina: Lecciones de Ciudad de México  Los programas de colaboración ciudadana son ampliamente percibidos y presentados como una importante solución para los apremiantes problemas de inseguridad en las ciudades latinoamericanas de hoy, y para mejorar las relaciones entre la ciudadanía y la policía. Basándonos en los resultados de trabajo de campo realizado en Ciudad de México, en el presente artículo se ofrece un análisis crítico del programa local de policía comunitaria y se demuestra que está excesivamente determinado por un contexto local caracterizado por el clientelismo, las lealtades políticas y la corrupción policial. Por eso, el aporte del programa a un mejoramiento sustentable de la rendición de cuentas local y de legitimidad policial es improbable. Contra este telón de fondo, en el artículo se demandan más estudios empíricos sobre el tema y una mayor sensibilidad para la integración de los programas de policía comunitaria dentro de un contexto político más amplio.

  1. Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

    Directory of Open Access Journals (Sweden)

    V. Mugica

    2002-01-01

    Full Text Available With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas, asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

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

    Science.gov (United States)

    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.

  3. Contralateral Autologous Corneal Transplantation Experience in Mexico City.

    Science.gov (United States)

    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.

  4. Health Reform in Mexico City, 2000-2006

    Directory of Open Access Journals (Sweden)

    Asa Cristina Laurell

    2008-07-01

    Full Text Available With the goal of fully guaranteeing the constitutional right to health protection, Mexico City’s leftist administration (2000-2006 undertook a reform to provide health services to people without insurance. The reform had four components: free medicine and health services; the introduction of a new service model (MAS; the strengthening, expansion, and improvement of services, and legislation to ensure that the city government become guarantor of this constitutional right. The reform resulted in 95% of eligible families being enrolled in free care; expansion of health care infrastructure with the construction of five new health care centers and a 1/3 increase in the number of public hospital beds in impoverished and disadvantaged areas; increased access to and use of health services particularly by the poor and for expensive interventions; and the legal guarantee of the continuity of this policy. The implementation of this new policy was made possible through an 80% budget increase, improvements in efficiency, and a successful fight against corruption. The health impact of the reform was seen in decline of mortality rates in all age groups between 1997 and 2005 (22% for child mortality, 11% for economically active age groups, and 7.9% for retired age groups and by a 16% decline in AIDS related mortality between 2000 and 2005. This reform contrasts with the health care reform promoted by the right wing Federal government in the rest of the country; the latter was based on voluntary health insurance, cost-sharing by families, access to a limited package of services, and gradual enrollment of the population

  5. Mass movement processes associated with volcanic structures in Mexico City

    Directory of Open Access Journals (Sweden)

    Víctor Carlos Valerio

    2012-11-01

    Full Text Available Mexico City, one of the most populated areas of the world, has been affected by various hazards of natural origin, such as subsidence and cracking of the soil, seismicity, floods and mass movement processes (MMPs. Owing to the lack of space on the plain, in recent years urban growth has been concentrated particularly on the slopes of the surrounding mountain ranges, and this has significantly modified the dynamics of the relief as well as the hydrogeological conditions. The specific character of natural susceptibility to mass movements is strongly dependent on the geological–structural and morphological characteristics of the volcanic bodies that form the mountainous relief. This natural susceptibility, combined with the characteristics of vulnerability of the society, creates risk conditions that can generate severe consequences for the population and the economy. Hence, based on an inventory of mass movement processes comprising 95 data points, the present study aimed to achieve a zoning of the areas susceptible to these processes, as well as to characterize the mechanisms of instability in the volcanic structures that form the relief of the area in question. The results of this work clearly show the role of the lithology, the mode of emplacement and the morpho–structural characteristics of the volcanic structures, in the types of mass movement processes. In addition, it identifies the diverse activities of anthropogenic origin that favour slope instability in the zone: deforestation and burning of rubbish, felling of timber on the slopes for building infrastructure and dwellings, leakages of water, vibrations of vehicles, rotating machinery and the use of explosives in mining works, overloading the heads of the slopes, disturbance of the geohydrological regime, generation of rubbish tips, terracing of the slopes for cultivation, inadequate building regulations, and the use of counterproductive or ineffectual stabilization measures.

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

    Science.gov (United States)

    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.

  7. On the vertical distribution of pollutants in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Perez Vidal, H. [Universidad Juarez Autonoma de Tabasco, Division Academica de Ciencias Basicas, Tabasco (Mexico); Raga, G. B. [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico)

    1998-04-01

    The problem of air pollution in Mexico City is studied through the analysis of a large dataset obtained by an instrumented aircraft during February 1991. These data constitute a unique set in Mexico and provide insight into the vertical structure of the boundary layer and the pollutant species which has not been previously discussed. The results obtained on the evolution and structure of the mixed layer indicate that its height rises from 100 meters during the morning (8 am) to over 2000 meters al 5 pm. results consistently show that the maximum in ozone concentration is not observed al the surface, but al about 700 m on average about it near midday. The peak, with an average concentration over the observational period of 167 ppb, appears to be a transient feature, with concentrations becoming more uniform with height in the afternoon. The vertical profiles of nitrogen oxides and sulphur dioxide indicate that concentrations are highest during the morning and steadily decrease with height, suggesting that sources for these species are located near the surface, as was expected. There appears to be no correlation between the amount of nitrogen oxides observed during the take-off and the ozone concentrations observed during landing (2-3 hours later). When the variables are normalized by the mixed layer height the results indicate that the ozone observed is fairly independent of the nitrogen oxide concentrations observed earlier. A reduced range of values of the ratio of ozone accumulated in the mixed layer and the layer height is consistently day found during the observational period. Aerosol particles near the surface show maximum concentration during the morning hours, but in contrast, during the course of the day, there is a marked increase in their concentrations at higher levels in the boundary layer suggesting that possibly gas to particle conversion is responsible for the observed increase. [Spanish] El problema de la contaminacion del aire en la Ciudad de

  8. 76 FR 73595 - Healthcare Technology, Policy & Trade Mission: Mexico City, Mexico, May 13-16, 2012

    Science.gov (United States)

    2011-11-29

    ... medical technology industries in Mexico. Participating in an official U.S. industry delegation, rather... pronouncement of regulations for medical technologies, Mexico is expected to become an even more attractive... technology industries; (2) to get a first-hand look at current use of healthcare technology in Mexico's top...

  9. Thirty years of social housing in Mexico City: new necessities and requirements

    OpenAIRE

    Villavicencio Blanco, Judith; Durán Contreras, Ana María

    2007-01-01

    For more than thirty years the state has supported important investment in social housing, but in Mexico and especially in Mexico City, serious problems of housing still persist. In order to overcome these problems not only enough resources and a housing policy with a clear social emphasis are required but, also, programs that take into account limitations that are detected observing the way homes are used by the families that inhabitant them must be implemented. The aspects that we have hav...

  10. Clients' reports on postabortion family planning services provided in Mexico City's public sector legal abortion program

    Science.gov (United States)

    Becker, Davida; Díaz-Olavarrieta, Claudia; Garcia, Sandra G.; Harper, Cynthia C.

    2014-01-01

    Objective First trimester abortion was decriminalized in Mexico City in 2007. We studied client views of family planning services provided during abortion care at public facilities and acceptance of postabortion contraception. Methods We surveyed 402 clients seeking first trimester abortion care in Mexico City. We used logistic regression to test whether postabortion contraception varied by abortion visit characteristics or client sociodemographics. Results Most participants (81.6%) reported being offered contraception at their visit and 89.5% selected a contraceptive method postabortion, with 58.9% selecting the IUD. Surgical abortion clients were more likely to report being offered contraception than medical abortion clients (p<.001), as were clients attended by a female physician (p<.05). Clients at the general hospital were less likely to report being offered contraception (p<.001). Conclusion Public sector facilities in Mexico City are providing a generally high level of postabortion family planning care and uptake of postabortion contraception is high. PMID:23499047

  11. Influence of urban ozone in the measurements of the total ozone column in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Juarez, A.; Gay, C. [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico); Bravo, J. L. [Instituto de Geofisica, UNAM, Mexico, D.F. (Mexico)

    1995-01-01

    In this paper we examine measurements of the thickness of the total ozone column between 1986 and 1989 in Mexico City. We consider the contribution of the surface ozone in measurement of the total ozone column made with the Dobson Spectrophotometer located at the Solar Radiation Laboratory (National University), in the southwest of Mexico City. We consider different depths of the mixing layer depending on the season and we compare our results with those reported for Mauna Loa in Hawaii and Poona in India, at the same latitude as Mexico City. In conclusion we confirm that in highly polluted areas the surface ozone has an important effect on measurements of the total ozone column. [Spanish] En este trabajo se examinan las mediciones del grosor de la columna total de ozono entre 1986 y 1989 en la Ciudad de Mexico. En esta revision se considera la contribucion del ozono superficial a las mediciones efectuadas con el Espectrofotometro Dobson instalado en el Laboratorio de Radiacion Solar de la UNAM al suroeste de la Ciudad de Mexico. Consideramos diferentes capas de mezcla para el ozono dependiendo del periodo estacional y comparamos los resultados obtenidos con los valores de las mediciones reportadas para Mauna Loa en Hawai y Poona en la India, ambos a latitudes similares a la de la Ciudad de Mexico. Nuestra conclusion es que en regiones urbanas con alta contaminacion ambiental, el ozono superficial afecta apreciablemente las mediciones del grosor de la columna total de ozono.

  12. A survey of 222Rn in drinking water in mexico city

    International Nuclear Information System (INIS)

    Vasquez-Lopez, C.; Zendejas-Leal, B. E.; Golzarri, J. I.; Espinosa, G.

    2011-01-01

    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. (authors)

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

    Science.gov (United States)

    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.

  14. New information on regional subsidence and soil fracturing in Mexico City Valley

    Directory of Open Access Journals (Sweden)

    G. Auvinet

    2015-11-01

    Full Text Available In this paper, updated information about regional subsidence in Mexico City downtown area is presented. Data obtained by R. Gayol in 1891, are compared with information obtained recently from surveys using the reference points of Sistema de Aguas de la Ciudad de México (2008 and on the elevation of a cloud of points on the ground surface determined using Light Detection and Ranging (LiDAR technology. In addition, this paper provides an overview of recent data obtained from systematic studies focused on understanding soil fracturing associated with regional land subsidence and mapping of areas susceptible to cracking in Mexico City Valley.

  15. Urban Leakage of Liquefied Petroleum Gas and Its Impact on Mexico City Air Quality

    Science.gov (United States)

    Blake, Donald R.; Sherwood Rowland, F.

    1995-08-01

    Alkane hydrocarbons (propane, isobutane, and n-butane) from liquefied petroleum gas (LPG) are present in major quantities throughout Mexico City air because of leakage of the unburned gas from numerous urban sources. These hydrocarbons, together with olefinic minor LPG components, furnish substantial amounts of hydroxyl radical reactivity, a major precursor to formation of the ozone component of urban smog. The combined processes of unburned leakage and incomplete combustion of LPG play a significant role in causing the excessive ozone characteristic of Mexico City. Reductions in ozone levels should be possible through changes in LPG composition and lowered rates of leakage.

  16. New information on regional subsidence and soil fracturing in Mexico City Valley

    Science.gov (United States)

    Auvinet, G.; Méndez-Sánchez, E.; Juárez-Camarena, M.

    2015-11-01

    In this paper, updated information about regional subsidence in Mexico City downtown area is presented. Data obtained by R. Gayol in 1891, are compared with information obtained recently from surveys using the reference points of Sistema de Aguas de la Ciudad de México (2008) and on the elevation of a cloud of points on the ground surface determined using Light Detection and Ranging (LiDAR) technology. In addition, this paper provides an overview of recent data obtained from systematic studies focused on understanding soil fracturing associated with regional land subsidence and mapping of areas susceptible to cracking in Mexico City Valley.

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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, and 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.

  2. The production and persistence of ΣRONO2 in the Mexico City plume

    Directory of Open Access Journals (Sweden)

    H. B. Singh

    2010-08-01

    Full Text Available Alkyl and multifunctional nitrates (RONO2, ΣANs have been observed to be a significant fraction of NOy in a number of different chemical regimes. Their formation is an important free radical chain termination step ending production of ozone and possibly affecting formation of secondary organic aerosol. ΣANs also represent a potentially large, unmeasured contribution to OH reactivity and are a major pathway for the removal of nitrogen oxides from the atmosphere. Numerous studies have investigated the role of nitrate formation from biogenic compounds and in the remote atmosphere. Less attention has been paid to the role ΣANs may play in the complex mixtures of hydrocarbons typical of urban settings. Measurements of total alkyl and multifunctional nitrates, NO2, total peroxy nitrates (ΣPNs, HNO3 and a representative suite of hydrocarbons were obtained from the NASA DC-8 aircraft during spring of 2006 in and around Mexico City and the Gulf of Mexico. ΣANs were observed to be 10–20% of NOy in the Mexico City plume and to increase in importance with increased photochemical age. We describe three conclusions: (1 Correlations of ΣANs with odd-oxygen (Ox indicate a stronger role for ΣANs in the photochemistry of Mexico City than is expected based on currently accepted photochemical mechanisms, (2 ΣAN formation suppresses peak ozone production rates by as much as 40% in the near-field of Mexico City and (3 ΣANs play a significant role in the export of NOy from Mexico City to the Gulf Region.

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

    Science.gov (United States)

    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.

  4. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

    OpenAIRE

    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; de Lourdes Munoz, Maria

    2011-01-01

    Abstract 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 ...

  5. Inhalant drug use and street youth : Ethnographic insights from Mexico City

    NARCIS (Netherlands)

    Gigengack, Roy; Preedy, Victor

    2016-01-01

    The inhalation of volatile substances with intentions of intoxication affects the lives of marginalized youths around the globe, but remains poorly understood. Based upon long-term ethnographic enquiry, this chapter describes the inhalant use of Mexico City's young street people from their

  6. The Chemo and the Mona: Inhalants, devotion and street youth in Mexico City

    NARCIS (Netherlands)

    Gigengack, R.A.

    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

  7. The chemo and the mona : Inhalants, devotion and street youth in Mexico city

    NARCIS (Netherlands)

    Gigengack, Roy

    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

  8. Cluster Analysis of the Wind Events and Seasonal Wind Circulation Patterns in the Mexico City Region

    Directory of Open Access Journals (Sweden)

    Susana Carreón-Sierra

    2015-07-01

    Full Text Available The residents of Mexico City face serious problems of air pollution. Identifying the most representative scenarios for the transport and dispersion of air pollutants requires the knowledge of the main wind circulation patterns. In this paper, a simple method to recognize and characterize the wind circulation patterns in a given region is proposed and applied to the Mexico City winds (2001–2006. This method uses a lattice wind approach to model the local wind events at the meso-β scale, and hierarchical cluster analysis to recognize their agglomerations in their phase space. Data of the meteorological network of Mexico City was used as input for the lattice wind model. The Ward’s clustering algorithm with Euclidean distance was applied to organize the model wind events in seasonal clusters for each year of the period. Comparison of the hourly population trends of these clusters permitted the recognition and detailed description of seven circulation patterns. These patterns resemble the qualitative descriptions of the Mexico City wind circulation modes reported by other authors. Our method, however, permitted also their quantitative characterization in terms of the wind attributes of velocity, divergence and vorticity, and an estimation of their seasonal and annual occurrence probabilities, which never before were quantified.

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

    Science.gov (United States)

    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…

  10. 3 CFR - Mexico City Policy and Assistance for Voluntary Population Planning

    Science.gov (United States)

    2010-01-01

    ... Population Planning Presidential Documents Other Presidential Documents Memorandum of January 23, 2009 Mexico City Policy and Assistance for Voluntary Population Planning Memorandum for the Secretary of State [and... awards, and subsequently extended the policy to “voluntary population planning” assistance provided by...

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

    Science.gov (United States)

    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,…

  12. Profile of gay men in Mexico City: results of a survey of meeting sites.

    Science.gov (United States)

    Gutiérrez, Juan Pablo

    2012-03-01

    To describe the distribution, size and characteristics of formal and non-formal meeting places for gay men in Mexico City, the general characteristics of this population, and the factors influencing HIV status and sexual behaviour among gay men. Meeting sites for gay men in Mexico City were mapped, and the results were used as a sampling frame for an individual-level survey. For the survey, a random sample of sites was selected using a selection probability proportional to size, with the aim of interviewing approximately 3000 gay men. Multivariate logistic models were constructed to analyse the correlations between the population profile, and characteristics and behaviours related to HIV status. Mapping produced an estimated population attending these meeting places in Mexico City of about 6000-14 000 gay men, who were mostly young and economically active individuals with higher educational and socioeconomic levels than the average levels of the population as a whole. Approximately 67% of these men reported being tested for HIV at least once, and 30% of the men reported being HIV-positive. Participants' profile depicted the gay population in Mexico City as a highly educated community with a relatively high socioeconomic level. Despite their exposure to prevention efforts, members of this community reported unsafe behaviours consistent with the high prevalence of self-reported HIV infection. © 2011 Blackwell Publishing Ltd.

  13. A modeling study of aeolian erosion enhanced by surface wind confluences over Mexico City

    Science.gov (United States)

    Using erosion and air quality models, a study on the effect of PM10 episodes in Mexico City is presented. The important contribution of Aeolian erosion on urban air quality, its genesis, morphology, location and regional implications such as the role played by surface confluences, the dry Lake of T...

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

    Science.gov (United States)

    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.

  15. Brillouin, Prof. Leon

    Indian Academy of Sciences (India)

    Home; Fellowship. Fellow Profile. Elected: 1939 Honorary. Brillouin, Prof. Leon. Date of birth: 7 August 1889. Date of death: 4 October 1969 ... Posted on 21 December 2017. ASTROPHYSICS: An Observational View of the Universe. Math Art and Design: MAD about Math, Math Education and Outreach. Math and Finance ...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. A scenario of human thermal comfort in Mexico City for 2CO{sub 2} conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui, Ernesto [Centro de Ciencias de la Atmosfera de la UNAM, Mexico, D.F. (Mexico); Tejeda, Adalberto [Universidad Veracruzana, Xalapa, Veracruz (Mexico)

    2001-07-01

    Applying the concept of effective temperature (ET), a scenario of human bioclimatic conditions for Mexico City is presented by using results from both GCM regional predictions for CO{sub 2} doubling and temperature trend projections from an urban station. Current and future bioclimatic maps for Mexico City and their conurbation are presented. Current environmental conditions will likely change toward a warmer atmosphere due to both the urbanization process and global greenhouse effect. The impact on the population will be more important during the warm season (March- May) when the bioclimate of the city will likely shift away from current neutrality to the next comfort scale category (ET 24-27 Celsius degrees) of warm conditions covering most of the capital city. [Spanish] A partir de la aplicacion del concepto de temperatura efectiva (ET) se presenta un escenario de las condiciones de bioclima humano para la Ciudad de Mexico y zona conurbada para la segunda mitad del proximo siglo. Se usaron resultados de predicciones regionales de modelos de circulacion general (GCM) para una duplicacion del CO{sub 2} y tambien las tendencias de temperatura de una estacion urbana. Se muestran mapas de las condiciones actuales y futuras de confort termico. La combinacion del efecto invernadero y la urbanizacion, muy probablemente impacten en la poblacion principalmente en la estacion calida (marzo a mayo), cuando se pase de la categoria de confort actual a la inmediata superior (ET 24-27 Celsius degrees) en la mayor parte de la capital del pais.

  19. Determination of radon levels in Mexico City; Determinacion de niveles de radon en la Ciudad de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Pena G, P

    1992-01-15

    The study of the determination of radon levels in the houses room in Mexico City is part of the project Emanometry of the radon. To carry out this study, the passive method was used, which consists of: thin film dosemeter of cellulose nitrate, container of the same one and spark accountant. The method is based on the mensurations of exhibition of the number of marks of alpha track is of the open type and it allows to average the radon activity along several weeks and it presents low concentrations. This study was carried out in 4 periods of exhibition of 3 months each one. (Author)

  20. Vehicular Diesel control emissions benefit assessment in Mexico City

    Science.gov (United States)

    Garcia-Reynoso, J.; Jazcilevich, A. D.; Ruiz-Suarez, L.; Cruz-Nuñez, X.; Rojas, A. R.; Tripp, M. R.

    2013-12-01

    Diesel vehicles contribute in an important proportion to the particle and black carbon (BC) ambient concentrations in urban areas. These pollutants can effect the climate and health. The average age of the Diesel fleet in Mexico is 15 year-old. An introduction of new technologies and retrofit systems can reduce emissions from this type of vehicles. A set of policies were selected and applied in order to identify their economic benefits in health. An air quality model was used to obtain ambient concentrations from the emissions and specific methodology for emissions inventory adjustment was developed for this project. Preliminary results show an important benefit due to the improvement of the emissions reduction from the Diesel fleet. PM2.5 differences for reduction scenario case 1 and base case. Output from WRF-chem using 2005 Naional Emissions Inventory Reductions obtained using data from the initial fleet, fleet temporal variation and substitution policies.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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 Mexico City women, which allows suppose that western culture influence can be the responsible.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Paola A Campos

    2017-01-01

    Full Text Available Objective. To document the frequency and forms of street harassment and examine the association between street harassment experiences and perceptions of social cohesion. Materials and methods. Baseline survey data collected among women seeking care in public health clinics in Mexico City were used for analysis. Results. 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. Conclusions. Findings indicate reducing street harassment may have important implications for improving women’s perceived social cohesion and their safety in Mexico City.

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

    Science.gov (United States)

    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

  7. Contribution of Liquefied Petroleum Gas to Air Pollution in the Metropolitan Area of Mexico City.

    Science.gov (United States)

    Gamas, Erick D; Magdaleno, Moises; Diaz, Luis; Schifter, Isaac; Ontiveros, Luis; Alvarez-Cansino, G

    2000-02-01

    An estimation of hydrocarbon emissions caused by the consumption of liquefied petroleum gas (LPG) in the Metropolitan Area of Mexico City (MAMC) is presented. On the basis of experimental measurements at all points of handling, during the distribution process, and during the consumption of LPG in industrial devices and domestic appliances, an estimated 76,414 tons/year are released to the air. The most important contribution is found during the domestic consumption of LPG (70%); this makes the control initiatives available to the consumer. By developing a control program of LPG losses, a 77% reduction in emission is expected in a 5-yr period. The calculated amounts of LPG emissions when correlated with the consumption of LPG, combined with information from air samples from the MAMC, do not point to LPG emissions as the most important factor contributing to tropospheric ozone in the air in Mexico City.

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

    Science.gov (United States)

    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.

  9. Radon levels survey in the underground transport metro system in Mexico City

    International Nuclear Information System (INIS)

    Espinosa, G.

    1995-01-01

    The Metro underground transport system moves more than 8 million people daily across Mexico city. The average time a traveller remains inside the underground stations and tunnels is more than two hours. The airborne radon levels were measured, during the three months of summer, at 20 different stations, including the more deeply located halls. Stations were in different zones of the city. The radon concentration in underground corridors and stations varied from 60 Bq.m -3 to 350Bq.m 3 . The environmental factors, such as outside temperature, humidity, and days of rain were compiled in order to understand radon entry and transport better. (author)

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

    Science.gov (United States)

    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…

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

    OpenAIRE

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

    2017-01-01

    Objective. To document the frequency and forms of street harassment and examine the association between street harassment experiences and perceptions of social cohesion. Materials and methods. Baseline survey data collected among women seeking care in public health clinics in Mexico City were used for analysis. Results. 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 low...

  12. Sweetened beverages intake, hyperuricemia and metabolic syndrome. The Mexico City Diabetes Study.

    OpenAIRE

    Rubén López-Molina; Socorro Parra-Cabrera; Ruy López-Ridaura; María E González-Villalpando; Ele Ferrannini; Clicerio González-Villalpando

    2013-01-01

    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...

  13. Modeling the impacts of biomass burning on air quality in and around Mexico City

    OpenAIRE

    W. Lei; G. Li; L. T. Molina

    2013-01-01

    The local and regional impacts of open fires and trash burning on ground-level ozone (O[subscript 3]) and fine carbonaceous aerosols in the Mexico City Metropolitan Area (MCMA) and surrounding region during two high fire periods in March 2006 have been evaluated using WRF-CHEM model. The model captured reasonably well the measurement-derived magnitude and temporal variation of the biomass burning organic aerosol (BBOA), and the simulated impacts of open fires on organic aerosol (OA) were cons...

  14. Modeling the impacts of biomass burning on air quality in and around Mexico City

    OpenAIRE

    W. Lei; G. Li; L. Molina

    2012-01-01

    The local and regional impacts of open fires and trash burning on ground-level ozone (O3) and fine carbonaceous aerosols in the Mexico City Metropolitan Area (MCMA) and surrounding region during two high fire periods in March 2006 have been evaluated using WRF-CHEM model. The model captured reasonably well the measurement-derived magnitude and temporal variation of the biomass burning organic aerosol (BBOA), and the simulated impacts of open fires on organic aerosol (OA...

  15. Antibiotic of resistence profile of Salmonella spp. serotypes isolated from retail beef in Mexico City.

    OpenAIRE

    Nova Nayarit-Ballesteros; María Salud Rubio-Lozano; Enrique Delgado-Suárez; Danilo Méndez-Medina; Diego Braña-Varela; Oscar Rodas-Suárez

    2016-01-01

    Objective. To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. Materials and methods. A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp). The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. Results. We isolated a total of 19 strains o...

  16. Characterization of Escherichia coli causing community acquired urinary tract infections in Mexico City.

    Science.gov (United States)

    Belmont-Monroy, Laura; Ribas-Aparicio, Rosa María; Navarro-Ocaña, Armando; Manjarrez-Hernández, H Ángel; Gavilanes-Parra, Sandra; Aparicio-Ozores, Gerardo; Cauich-Sánchez, Patricia Isidra; Garza-Ramos, Ulises; Molina-López, José

    2017-02-01

    The O25-ST131 clone was identified within 169 uropathogenic Escherichia coli (UPEC) strains. The 44.8% of the 29 O25-ST131 clones detected were positive to least to one extended-spectrum β-lactamase gene. The phylogroup D was mainly found. The O25-ST131 clone appeared to be associated with community-acquired UTI in Mexico City. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  19. A Historical Perspective on Crime in Twentieth-Century Mexico City

    OpenAIRE

    Piccato, Pablo

    2003-01-01

    This paper is an overview of perceptions of crime in Mexico City during the twentieth century. After a brief review of quantitative evidence and the main sources on crime, the paper surveys police and judicial corruption as the common denominator of public perceptions of crime, punishment, and the judiciary. The paper then discusses gender violence and juvenile delinquency as two criminal practices that have characterized the impact of crime in everyday life. Based on a review of evidence abo...

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

    Science.gov (United States)

    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.

  1. Development and testing of an air quality model for Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M.D.; Streit, G. (Los Alamos National Lab., NM (United States)); Cruz, X.; Ruiz, M.; Sosa, G. (Instituto Mexicano de Petroleo, Mexico City (Mexico)); Russell, A.G.; McNair, L.A. (Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Mechanical Engineering)

    1992-03-02

    Los Alamos National Laboratory and Instituto Mexicano del Petroleo have embarked on a joint study of options for improving air quality in Mexico City. The intent is to develop a modeling system which can address the behavior of pollutants in the region so that option for improving Mexico City air quality can be properly evaluated. In February of 1991, the project conducted a field program which yielded a variety of data which is being used to evaluate and improve the models. Normally the worst air quality for both primary and photochemical pollutants occurs in the winter Mexico City. 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 earth surface skin temperatures, and (4) tethersonde measurements of wind, temperature and ozone vertical profiles. A three-dimensional, prognostic, higher order turbulence meteorological model (HOTMAC) was modified to include an urban canopy and urban heat sources. HOTMAC is used to drive an Monte-Carlo kernel dispersion code (RAPTAD). HOTMAC also provides winds and mixing heights for the CIT photochemical model which was developed by investigators at the California Institute of Technology and Carnegie Mellon University.

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

    Science.gov (United States)

    Ortiz, Rutilio; Vega, Salvador; Gutiérrez, Rey; Gibson, Richard; Schettino, Beatriz; Ramirez, María de Lourdes

    2012-03-01

    A soil survey was carried out to determine the levels and sources and concentrations of 16 polycyclic aromatic hydrocarbons in 2 semi-rural terrains in Mexico City (Tlahuac and Milpa Alta) during 2008-2009. PAH determination was made by Soxhlet extraction and chromatographic clean-up with final analysis by gas chromatography with a flame ionization detector. The concentrations in Tlahuac were 9.13 mg/kg (dry season) and 11.22 mg/kg (wet season) and in Milpa Alta were 11.43 mg/kg (dry season) and 35.77 mg/kg (wet season). The variation of total PAH concentrations are due to environmental and anthropogenic conditions within Mexico City and also the addition of compost to the soils. According to Mexican regulations BaP, DaA, BbF and Ind were within the permissible limit (2 mg/kg) for agricultural and residential soils and BkF was close to the limit (8 mg/kg). The total PAH concentrations do however surpass the permissible European limit of 1,000 μg/kg and there is probably some risk to human health, in spite of measures aimed at decreasing contamination in Mexico City. Long term monitoring of soils will be necessary.

  3. Uncertainties in SOA simulations due to meteorological uncertainties in Mexico City during MILAGRO-2006 field campaign

    Science.gov (United States)

    Bei, N.; Li, G.; Molina, L. T.

    2013-05-01

    The purpose of the present study is to investigate the uncertainties in simulating secondary organic aerosol (SOA) in Mexico City metropolitan area (MCMA) due to meteorological initial uncertainties using the WRF-CHEM model through ensemble simulations. The simulated periods (24 and 29 March 2006) represent two typical meteorological episodes ("Convection-South" and "Convection-North", respectively) in the Mexico City basin during the MILAGRO-2006 field campaign. The organic aerosols are simulated using a non-traditional SOA model including the volatility basis-set modeling method and the contributions from glyoxal and methylglyoxal. Model results demonstrate that uncertainties in meteorological initial conditions have significant impacts on SOA simulations, including the peak time concentrations, the horizontal distributions, and the temporal variations. The ensemble spread of the simulated peak SOA at T0 can reach up to 4.0 μg m-3 during the daytime, which is around 35% of the ensemble mean. Both the basin wide wind speed and the convergence area affect the magnitude and the location of the simulated SOA concentrations inside the Mexico City basin. The wind speed, especially during the previous midnight and the following early morning, influences the magnitude of the peak SOA concentration through ventilation. The surface horizontal convergence zone generally determines the area with high SOA concentrations. The magnitude of the ensemble spreads may vary with different meteorological episodes but the ratio of the ensemble spread to mean does not change significantly.

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

    Science.gov (United States)

    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.

  5. Recent trends and challenges in three large Mexican cities: Mexico City, Guadalajara and Monterrey

    Directory of Open Access Journals (Sweden)

    Juan Manuel Ramírez Sáiz

    2009-07-01

    Full Text Available In this paper we analyze a series of factors or aspects in three large contemporary Mexican cities: multi-culturality, inequality, social and urban fragmentation, public insecurity and conflicting conceptions of what the city should be. The article offers an overview of the current situation, on the basis of the authors’ own research projects and a review of recent literature on the topic. It is therefore primarily a theoretical paper

  6. Microscopic Characterization of Carbonaceous Aerosol Particle Aging in the Outflow from Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Moffet, R. C.; Henn, T. R.; Tivanski, A. V.; Hopkins, R. J.; Desyaterik, Y.; Kilcoyne, A. L. D.; Tyliszczak, T.; Fast, J.; Barnard, J.; Shutthanandan, V.; Cliff, S.S.; Perry, K. D.; Laskin, A.; Gilles, M. K.

    2009-09-16

    This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City Metropolitan Area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (~;;29 km and ~;;65 km, respectively), the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

  7. Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

    Science.gov (United States)

    Moffet, R. C.; Henn, T. R.; Tivanski, A. V.; Hopkins, R. J.; Desyaterik, Y.; Kilcoyne, A. L. D.; Tyliszczak, T.; Fast, J.; Barnard, J.; Shutthanandan, V.; Cliff, S. S.; Perry, K. D.; Laskin, A.; Gilles, M. K.

    2010-02-01

    This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City metropolitan area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (~29 km and ~65 km, respectively), the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. 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.

  9. Sociodemographic factors associated with obstacles to abortion care: findings from a survey of abortion patients in Mexico City.

    Science.gov (United States)

    Becker, Davida; Diaz-Olavarrieta, Claudia; Juarez, Clara; Garcia, Sandra G; Sanhueza Smith, Patricio; Harper, Cynthia C

    2011-01-01

    First-trimester abortion was legalized in Mexico City in 2007, and services are now provided at public and private sites throughout the city. However, little is known about the obstacles women face when seeking abortion care. We surveyed women who obtained abortion services (n = 398) at three public sector facilities in Mexico City to identify the obstacles women faced when obtaining abortions. We used logistic regression to test whether obstacles varied by sociodemographic characteristics. Women with low education were more likely than high school-educated women to report difficulty getting appointments. Unmarried women and women with low education were more likely than married women or high school educated women to report difficulty getting time off work for appointments and arranging for transportation to the facility. Separated or divorced women were more likely than married women to report partner or other family member opposition to the abortion. Women who lived outside of Mexico City were more likely than Mexico City residents to report difficulty with transportation. Education, marital status, and place of residence were associated with the obstacles women reported. Strategies to improve access to care should be targeted to the groups at highest risk of experiencing obstacles: Women with primary education or lower, single women, separated/divorced women, and those residing outside of Mexico City. Copyright © 2011 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 a closed-end cup system with CR-39 (Lantrack®) polycarbonate as detector material. The indoor radon concentrations were found to be between 75 and 170 Bq m −3 , below the USEPA-recommended indoor radon action level for working places of 400 Bq m −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

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

    Energy Technology Data Exchange (ETDEWEB)

    Juarez, Faustino [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100. Estado de Mexico, 50000, Mexico. Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Circuito (Mexico); Reyes, Pedro G. [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100. Estado de Mexico, 50000 (Mexico); Espinosa, Guillermo [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria, Mexico D.F. Cp.04510 (Mexico)

    2013-07-03

    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 a 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.

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

    Science.gov (United States)

    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.

  14. [Characterization of stroke patients attended at IMSS hospitals in Mexico City].

    Science.gov (United States)

    Torres-Arreola, Laura Del Pilar; Valenzuela-Flores, Adriana Abigail; Villa-Barragán, Juan Pablo

    2018-01-01

    Cerebrovascular disease (CD) is considered a problem of huge social, economic and public health implications worldwide in adults and elderly. In Mexico, the information concerning the provision of services to people and their characteristics is limited. The objective is to describe the characteristics of patients with CV who attended the hospitals of the Instituto Mexicano del Seguro Social (IMSS) in Mexico City. It was carried out a cohort study of patients with ischemic or hemorrhagic CD who arrived to IMSS. Patients were recruited from seven IMSS general hospitals in Mexico City from June, 2013, to October, 2014. We assigned 430 subjects with CD (78.14% had ischemic CD). There were no statistical differences regarding gender. The median age of patients was 74 years. During their first 72 hours of hospital stay, it was assessed language proficiency in 90%, the ability to walk in 16.3% and the ability to move extremities in 94%. The main risk factors were hypertension, 84%; diabetes mellitus, 46.3%; history of CD, 25.1%; smoking history, 13.7%. 80% of patients reported that their health was regular or poor. General characteristics of patients and vascular risk factors are similar to those reported by other studies. Secondary prevention strategies are performed in less time than that recommended by international standards. It is urgent to design strategies to build better ways of care during the acute phase of patients with CD.

  15. Comparative Analysis of Responses of Land Surface Temperature to Long-Term Land Use/Cover Changes between a Coastal and Inland City: A Case of Freetown and Bo Town in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Musa Tarawally

    2018-01-01

    Full Text Available Urban growth and its associated expansion of built-up areas are expected to continue through to the twenty second century and at a faster pace in developing countries. This has the potential to increase thermal discomfort and heat-related distress. There is thus a need to monitor growth patterns, especially in resource constrained countries such as Africa, where few studies have so far been conducted. In view of this, this study compares urban growth and temperature response patterns in Freetown and Bo town in Sierra Leone. Multispectral Landsat images obtained in 1998, 2000, 2007, and 2015 are used to quantify growth and land surface temperature responses. The contribution index (CI is used to explain how changes per land use and land cover class (LULC contributed to average city surface temperatures. The population size of Freetown was about eight times greater than in Bo town. Landsat data mapped urban growth patterns with a high accuracy (Overall Accuracy > 80% for both cities. Significant changes in LULC were noted in Freetown, characterized by a 114 km2 decrease in agriculture area, 23 km2 increase in dense vegetation, and 77 km2 increase in built-up area. Between 1998 and 2015, built-up area increased by 16 km2, while dense vegetation area decreased by 14 km2 in Bo town. Average surface temperature increased from 23.7 to 25.5 °C in Freetown and from 24.9 to 28.2 °C in Bo town during the same period. Despite the larger population size and greater built-up extent, as well as expansion rate, Freetown was 2 °C cooler than Bo town in all periods. The low temperatures are attributed to proximity to sea and the very large proportion of vegetation surrounding the city. Even close to the sea and abundant vegetation, the built-up area had an elevated temperature compared to the surroundings. The findings are important for formulating heat mitigation strategies for both inland and coastal cities in developing countries.

  16. A Brief Overview of INTEX-B and OVOC Observations Over Mexico City, Gulf of Mexico, and the Pacific Ocean

    Science.gov (United States)

    Singh, H. B.; Apel, E.; Brune, W.; Carmichael, G.; Cohen, R.; Crawford, J.; Czech, E.; Emmons, L.; Flocke, F.; Fried, A.; Fuelberg, H.; Heikes, B.; Jacob, D.; Pierce, B.

    2007-12-01

    INTEX-B/MILAGRO* was a major international atmospheric chemistry field campaign completed in the spring of 2006 (March 1-May 15). Airborne measurements of a large number of oxygenated volatile organic chemicals (OVOC) were carried out over Mexico City, Gulf of Mexico, and the Pacific Ocean using the NASA DC-8 and NSF/NCAR C-130. OVOC measurements included acetone, methylethyl ketone, methanol, ethanol, acetaldehyde, propanal, formaldehyde, organic peroxides, PANs, and organic nitrates. Complementary measurements of several tracers (CO, HCN) were also made. Throughout the troposphere mixing ratios of several OVOC were strongly correlated with each other as well as with tracers of fossil and biomass/biofuel combustion. The composition of these air masses also indicated a large shift of reactive nitrogen into the PAN reservoir during transport thereby limiting ozone formation. Several 3-D models (GEOS-Chem, MOZART, RAQMS, STEM) were used to simulate these observations with partial success. Some of these OVOC have also been retrieved from satellite observations in the upper troposphere and these data are compared. An analysis of the distribution and sources of OVOC based on INTEX-B/MILAGRO and some satellite observations will be presented. *INTEX-B: Intercontinental Chemical Transport Experiment-B; MILAGRO: Megacity Initiative: Local and Global Research Observations

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

    Science.gov (United States)

    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.

  18. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2008-08-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006. Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC mixed with nitrate and sulfate, elemental carbon (EC, nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42% which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m. showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m. showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m., weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m., resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh

  19. An Overview of the MILAGRO 2006 Campaign: Mexico City Emissions and their Transport and Transformation

    Energy Technology Data Exchange (ETDEWEB)

    Molina, Luisa T.; Madronich, Sasha; Gaffney, Jeffrey; Apel, Eric; de Foy, B.; Fast, Jerome D.; Ferrare, R.; Herndon, Scott C.; Jimenez, Jose L.; Lamb, Brian K.; Orsonio-Vargas, A. R.; Russell, P. B.; Schauer, James J.; Stevens, P. S.; Volkamer, Rainer M.; Zavala, Miguel A.

    2010-03-25

    The world’s population is projected to increase 33% during the next three decades, to 8.1 billion. Nearly all of the projected growth is expected to be concentrated in urban centers. These rapidly expanding urban regions and surrounding suburban areas are leading to the phenomenon of megacities (metropolitan areas with populations exceeding 10 million inhabitants). Well governed, densely populated settlements can reduce the need for land conversion and provide proximity to infrastructure and services. However, many urban areas experience uncontrolled sprawl and their activities are the leading cause of environmental problems. These mega-centers of human population are tied directly to increasing demands for energy and associated industrial activities and motorization that lead to more emission of pollutants into the atmosphere. Air pollution is one of the most important environmental challenges of this century. This challenge is particularly acute in the developing world where the rapid growth of megacities is producing atmospheric pollution of unprecedented severity and extent. MILAGRO (Megacity Initiative: Local And Global Research Observations) is the first international collaborative project to examine the behavior and the export of atmospheric pollutants generated in megacities. The Mexico City Metropolitan Area (MCMA) - one of the world’s largest megacities and North America’s most populous city -- was selected as the initial case study to characterize the sources and processes of emissions from the urban center and to evaluate the regional and global impacts of the Mexico City air pollution plume

  20. Mexico City air quality research initiative, volume 3, modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mauzy, A. [ed.] [Los Alamos National Lab., NM (United States)

    1994-06-01

    The objective of the modeling and simulation task was to develop, test, and apply an appropriate set of models that could translate emission changes into air quality changes. Specifically, we wanted to develop models that could describe how existing measurements of ozone (O{sub 3}), carbon monoxide (CO), and sulfur dioxide (SO{sub 2}) would be expected to change if their emissions were changed. The modeling must be able to address the effects of difference in weather conditions and changes in land use as well as the effects of changes in emission levels. It must also be able to address the effects of changes in the nature and distribution of the emissions as well as changes in the total emissions. A second objective was to provide an understanding of the conditions that lead to poor air quality in Mexico City. We know in a general sense that Mexico City`s poor air quality is the result of large quantities of emissions in a confined area that is subject to light winds, but we did not know much about many aspects of the problem. For example, is the air quality on a given day primarily the result of emissions on that day...or is there an important carryover from previous nights and days? With a good understanding of the important meteorological circumstances that lead to poor air quality, we learn what it take duce an accurate forecast of impending quality so that we can determine the advisability of emergency measures.

  1. Urban-Architectural vision of aesthetic paradigm and commerce, Historic Center, Mexico-City.

    Directory of Open Access Journals (Sweden)

    Maria Guadalupe Valiñas

    2017-01-01

    Full Text Available The aim of the article is to show a current perspective Historic center of Mexico City and its problematic is that excessive trade in this space harms the urban architectural heritage and then the aesthetics of it is hampered by his use trade in. The problem is to investigate this space to analyze how antagonistically articulates the relationship between trade and aesthetics in it. This place is the center of the city and the country, it is saturated with trade in its various forms, from commercial plazas, passages, markets, up to the street vendors, these elements in their relationship affect the damage of the Historic Center the Mexico City and contribute to the deterioration of the urban architectural aesthetics of the space. The main contributions of this work reflect the different adverse effects from trade to the detriment of the aesthetic aspect, which should be evaluated as depopulation, converting housing in warehouses, upholstering informal trade public space and damage to the landmarks in the area. The usefulness of the project is growing in relation to the direction they should take public policies to preserve that heritage for the sake of seeking environmental, social and economic welfare equitably strengthen the aesthetic appearance, which itself should be one of the main features of historical center given the cultural and historical significance of the site.

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

    Science.gov (United States)

    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.

  3. Contribution of garbage burning to chloride and PM2.5 in Mexico City

    Science.gov (United States)

    Li, G.; Lei, W.; Bei, N.; Molina, L. T.

    2012-09-01

    The contribution of garbage burning (GB) emissions to chloride and PM2.5 in the Mexico City Metropolitan Area (MCMA) has been investigated for the period of 24 to 29 March during the MILAGRO-2006 campaign using the WRF-CHEM model. When the MCMA 2006 official emission inventory without biomass burning is used in the simulations, the WRF-CHEM model significantly underestimates the observed particulate chloride in the urban and the suburban areas. The inclusion of GB emissions substantially improves the simulations of particulate chloride; GB contributes more than 60% of the observation, indicating that it is a major source of particulate chloride in Mexico City. GB yields up to 3 pbb HCl at the ground level in the city, which is mainly caused by the burning of polyvinyl chloride (PVC) in the garbage. GB is also an important source of PM2.5, contributing about 3-30% simulated PM2.5 mass on average. More modeling work is needed to evaluate the GB contribution to hazardous air toxics, such as dioxin, which is found to be released at high level from PVC burning in laboratory experiments.

  4. Contribution of garbage burning to chloride and PM2.5 in Mexico City

    Directory of Open Access Journals (Sweden)

    N. Bei

    2012-09-01

    Full Text Available The contribution of garbage burning (GB emissions to chloride and PM2.5 in the Mexico City Metropolitan Area (MCMA has been investigated for the period of 24 to 29 March during the MILAGRO-2006 campaign using the WRF-CHEM model. When the MCMA 2006 official emission inventory without biomass burning is used in the simulations, the WRF-CHEM model significantly underestimates the observed particulate chloride in the urban and the suburban areas. The inclusion of GB emissions substantially improves the simulations of particulate chloride; GB contributes more than 60% of the observation, indicating that it is a major source of particulate chloride in Mexico City. GB yields up to 3 pbb HCl at the ground level in the city, which is mainly caused by the burning of polyvinyl chloride (PVC in the garbage. GB is also an important source of PM2.5, contributing about 3–30% simulated PM2.5 mass on average. More modeling work is needed to evaluate the GB contribution to hazardous air toxics, such as dioxin, which is found to be released at high level from PVC burning in laboratory experiments.

  5. Implementation of a radiological safety management system in a hospital of Mexico City

    International Nuclear Information System (INIS)

    Martinez V, D.; Rivera M, T.; Velez D, V.

    2007-01-01

    Full text: The reflection of this work is based in some radiological accidents that its have happened in some hospital centers or of research. The over exposure of some people is due to the pursuit of the procedures, the lack of quality assurance of the equipment or the inappropriate actions of the technicians. In Mexico one has seen in several hospitals the lack of existence of a Quality Assurance Program to prevent the accidents, the execution of the same ones and those good practices and the lack of Safety Culture makes that the hospital radiological safety it is faulty. The objective of the present work is the implementation of a radiological safety management in a hospital of Mexico City. (Author)

  6. Perceptions of mental illness in Mexico: a descriptive study in the city of Chihuahua.

    Science.gov (United States)

    Parra, F

    1987-01-01

    This work is a study of perceptions toward mental illness among respondents from the city of Chihuahua in Mexico. A non-probability sample of forty-seven respondents was taken during a two-week stay in the summer of 1985. To tap respondents' perceptions of mental illness, vignettes characterizing people normally thought to have symptoms of mental illness were employed. The study reveals that men and women perceive mental illness differently. In three out of four vignettes, women perceive mental disorder than men. It is argued that the reason for the disparity in perceptions between the sexes is the result of the sexual differentiation that exists in Mexico. With regard to whom the respondents would refer the person for help, the majority of the respondents recommended that, whether or not the person in the vignette is characterized as mentally ill or simply "sick", the person should seek professional help.

  7. Identification of elements in polutants of Mexico City's atmosphere, using the pixe analysis

    International Nuclear Information System (INIS)

    Diaz-Godoy, R.V.

    1990-01-01

    A review of the fundamentals and actual state in Mexico of the pixe (particle induced X- ray emission) technique are done. Elemental identification in samples of Mexico City's atmosphere taken in two sites is performed using this technique. A 3 MeV proton beam is used to irradiate the samples. Factors (Bremsstrahlung and interference) that difficult the use of the technique are discussed. The sensitivity of the method is enhanced as a main characteristic. It is shown that tje pixe technique together with an appropriate sampling system can be used to study environmental aerosols. Identified elements are bromine, lead, copper, iron, zinc, titanium, vanadium, calcium, potassium, chlorine, sulfur and silicon. Temporal variations of these elements are discussed. (Author)

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

    Science.gov (United States)

    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.

  9. Sources and sinks of carbon dioxide in a neighborhood of Mexico City

    Science.gov (United States)

    Velasco, E.; Perrusquia, R.; Jiménez, E.; Hernández, F.; Camacho, P.; Rodríguez, S.; Retama, A.; Molina, L. T.

    2014-11-01

    Cities are the main contributors to the CO2 rise in the atmosphere. The CO2 released from the various emission sources is typically quantified by a bottom-up aggregation process that accounts for emission factors and fossil fuel consumption data. This approach does not consider the heterogeneity and variability of the urban emission sources, and error propagation can result in large uncertainties. These uncertainties might lead to unsound mitigation policies. Monitoring systems of greenhouse gases (GHG) based on independent methods are needed to validate the accuracy of the estimated emissions. In this context, direct measurements of CO2 fluxes that include all major and minor anthropogenic and natural sources and sinks from a specific district can be used to evaluate emission inventories. This study reports and compares CO2 fluxes measured directly using the eddy covariance (EC) method with emissions taken from the gridded local emissions inventory for the footprint covered by the EC flux system for a residential/commercial neighborhood of Mexico City. The flux measurements were conducted over 15-month period. No seasonal variability was found, but a clear diurnal pattern with morning and evening peaks in phase with the rush-hour traffic was observed. After adding contributions from human and soil respiration obtained by bottom-up approaches, and subtracting the CO2 sequestrated by vegetation calculated by applying biomass allometric equations and a growth predictive model to trees inventoried within the studied domain, results show that the current emissions inventory over-predicts 2.8 times the average daily flux measured on weekdays. Using traffic emissions data from a 2-year older inventory the difference decreased to 30%, suggesting that the traffic load for this part of the city is probably highly overestimated in the current emissions inventory. This study is expected to contribute to the verification capabilities of the GHG mitigation management of Mexico

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

    Directory of Open Access Journals (Sweden)

    D. A. Thornhill

    2008-06-01

    Full Text Available 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

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

    Science.gov (United States)

    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

  12. Sources and transformations of particle-bound polycyclic aromatic hydrocarbons in Mexico City

    Directory of Open Access Journals (Sweden)

    L. C. Marr

    2006-01-01

    Full Text Available Understanding sources, concentrations, and transformations of polycyclic aromatic hydrocarbons (PAHs in the atmosphere is important because of their potent mutagenicity and carcinogenicity. The measurement of particle-bound PAHs by three different methods during the Mexico City Metropolitan Area field campaign in April 2003 presents a unique opportunity for characterization of these compounds and intercomparison of the methods. The three methods are (1 collection and analysis of bulk samples for time-integrated gas- and particle-phase speciation by gas chromatography/mass spectrometry; (2 aerosol photoionization for fast detection of PAHs on particles' surfaces; and (3 aerosol mass spectrometry for fast analysis of size and chemical composition. This research represents the first time aerosol mass spectrometry has been used to measure ambient PAH concentrations and the first time that fast, real-time methods have been used to quantify PAHs alongside traditional filter-based measurements in an extended field campaign. Speciated PAH measurements suggest that motor vehicles and garbage and wood burning are important sources in Mexico City. The diurnal concentration patterns captured by aerosol photoionization and aerosol mass spectrometry are generally consistent. Ambient concentrations of particle-phase PAHs typically peak at ~110 ng m-3 during the morning rush hour and rapidly decay due to changes in source activity patterns and dilution as the boundary layer rises, although surface-bound PAH concentrations decay faster. The more rapid decrease in surface versus bulk PAH concentrations during the late morning suggests that freshly emitted combustion-related particles are quickly coated by secondary aerosol material in Mexico City's atmosphere and may also be transformed by heterogeneous reactions.

  13. Cost-effectiveness analysis of alternative first-trimester pregnancy termination strategies in Mexico City.

    Science.gov (United States)

    Hu, D; Grossman, D; Levin, C; Blanchard, K; Goldie, S J

    2009-05-01

    To assess the comparative health and economic outcomes associated with three alternative first-trimester abortion techniques in Mexico City and to examine the policy implications of increasing access to safe abortion modalities within a restrictive setting. Cost-effectiveness analysis. Mexico City. Reproductive-aged women with unintended pregnancy seeking first-trimester abortion. Synthesising the best available data, a computer-based model simulates induced abortion and its potential complications and is used to assess the cost-effectiveness of alternative safe modalities for first-trimester pregnancy termination: (1) hospital-based dilatation and curettage (D&C), (2) hospital-based manual vacuum aspiration (MVA), (3) clinic-based MVA and (4) medical abortion using vaginal misoprostol. Number of complications, lifetime costs, life expectancy, quality-adjusted life expectancy. In comparison to the magnitude of health gains associated with all safe abortion modalities, the relative differences between strategies were more pronounced in terms of their economic costs. Assuming all options were equally available, clinic-based MVA was the least costly and most effective. Medical abortion with misoprostol provided comparable benefits to D&C, but cost substantially less. Enhanced access to safe abortion was always more influential than shifting between safe abortion modalities. This study demonstrates that the provision of safe abortion is cost-effective and will result in reduced complications, decreased mortality and substantial cost savings compared with unsafe abortion. In Mexico City, shifting from a practice of hospital-based D&C to clinic-based MVA and enhancing access to medical abortion will have the best chance to minimise abortion-related morbidity and mortality.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Marley, N; Gaffney, J; Tackett, M J; Sturchio, N; Hearty, L; Martinez, N; Hardy, K D; Machany-Rivera, A; Guilderson, T P; MacMillan, A; Steelman, K

    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 absorbing 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.

  16. [Surveillance of antibiotic utilization and bacterial resistance profiles in tertiary level hospitals in Mexico City].

    Science.gov (United States)

    Benavides-Plascencia, Lilia; Aldama-Ojeda, Alejandro Leonardo; Javier Vázquez, Héctor

    2005-01-01

    To identify the levels of antibiotic utilization and the resistance profiles of nosocomial bacteria, as well as the strategies to diminish resistance to antibiotics. A descriptive, retrospective (1994-1995) study was conducted in six tertiary level hospitals in Mexico City. A total of 86% antibiotic resistance was observed in these hospitals. The overall consumption of antibiotics per hospital ranged between 44 and 195 Defined Daily Doses/100 day-beds. We identified the components to frame an integral surveillance system aimed at improving the use of antibiotics and the quality of the bacterial resistance assessment in these hospitals.

  17. Mexico City air quality research initiative. Volume IV. Characterization and measurement

    Energy Technology Data Exchange (ETDEWEB)

    Mauzy, A. [ed.

    1994-04-01

    This volume describes the methods and the data gathered in an attempt to measure and characterize the meteorological factors and the concentration of different pollutants in the Mexico City Metropolitan Area. The main objective of this document was to provide input for the simulation models and to obtain information that could be used to test and improve the models` performance. Four field campaigns were conducted, as well as routine monitoring, in order to obtain a database of atmospheric dynamics and air pollution characteristics. Sections include Airborne measurements, Remote sensing measurements, and Traditional (in situ) measurements.

  18. The polycentric structure of local labour markets in Mexico City's Metropolitan Area

    Directory of Open Access Journals (Sweden)

    José María Casado Izquierdo

    2012-11-01

    Full Text Available Commuting data at a district level and an algorithm designed to delineate self–contained areas show that Mexico City Metropolitan Area (MCMA was organized in 2007 in twelve local labour market areas. Although six exployment subcenters were identified, the MCMA is still clearly dominated by its Central Business District (CBD, being located the remaining five subcenters close to the CBD. Assessment of this spatial structure is not a positive one: diminishing co–location, decrease in speed and increase in commuting time and distance. Nevertheless, the rising percentage of intra–district commuting is a positive sign, even if this trend is not uniform throughout the metropolitan area.

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

    Science.gov (United States)

    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) (pmarketing and environmental modifications were effective on increasing water consumption among children, strategy that might contribute to mitigate childhood obesity.

  20. Blood lead levels in pregnant women of high and low socioeconomic status in Mexico City.

    OpenAIRE

    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 ...

  1. Risk Factor Frequency for Learning Disabilities in Low Socioeconomic Level Preschool Children in Mexico City

    OpenAIRE

    Zambrano-Sánchez, Elizabeth; Martínez-Wbaldo, María del Consuelo; Poblano, Adrián

    2010-01-01

    The objective was to identify the frequency of risk factors for Learning Disabilities (LD) in low socioeconomic level children in Mexico City. We studied children by means of: Wechsler, Bender-Gestalt, and Human drawing tests. Average age of male subjects was 5.6±0.9 years, while that of the female group was 5.4±0.5 years. In male subjects, average Total intelligence quotient (T-IQ) score was 98±12.2 while, in the female group, this was 99±12.2. On the Bender-Gestalt test, male subjects had a...

  2. Mexico.

    Science.gov (United States)

    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.

  3. PCBs and PAHs in surficial sediments from aquatic environments of Mexico City and the coastal states of Sonora, Sinaloa, Oaxaca and Veracruz (Mexico)

    Science.gov (United States)

    Piazza, Rossano; Ruiz-Fernández, Ana Carolina; Frignani, Mauro; Zangrando, Roberta; Bellucci, Luca Giorgio; Moret, Ivo; Páez-Osuna, Federico

    2008-06-01

    Concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were measured in 13 surficial sediment samples collected at three lacustrine locations in the surroundings of Mexico City and four coastal areas of the States of Sinaloa, Sonora, Oaxaca and Veracruz. Total PCB concentrations span the interval 3.18 621 ng g-1. The highest values (63.7 621 ng g-1) were found in Mexico City, which is a highly anthropogenically impacted area, whereas low concentrations (3.18 12.9 ng g-1) were characteristic of seven places, some of them subject to intense hydrodynamics. In these latter cases, values increase by 18 73 times if normalised against the fine fraction (silt plus clay) content in sediment. Two samples from Mexico City exceed the ERM (Effect Range Median) guidelines and are likely to cause adverse effects. Samples contain only lower chlorinated PCBs (mainly 2-, 3- and 4-CB), thus suggesting that the most used PCB commercial mixture was Aroclor 1242. The homologue composition of the sample taken close to the nuclear power plant of Laguna Verde is identical to this commercial mixture. PAHs in the same samples have relatively low concentrations (14.9 287 ng g-1), well below ERL (Effect Range Low) guidelines. The composition of PAH mixtures accounts for the influence of both petrogenic and pyrolitic sources, with these latter prevailing at some places in Mexico City.

  4. [Antibiotic of resistence profile of Salmonella spp. serotypes isolated from retail beef in Mexico City].

    Science.gov (United States)

    Nayarit-Ballesteros, Nova; Rubio-Lozano, María Salud; Delgado-Suárez, Enrique; Méndez-Medina, Danilo; Braña-Varela, Diego; Rodas-Suárez, Oscar

    2016-06-01

    To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp).The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. We isolated a total of 19 strains of Lomita (6), Derby (4), Senftenberg (2), Javiana and Cannsttat (1) and undetermined (5) serotypes. The strains showed a high resistance rate to ampicillin (18/19), carbenicillin (16/19), tetracyclin (13/19), and trimethoprim-sulfamethoxazole (13/19). Multidrug resistance was observed in 14 isolates. Several Salmonella spp. serotypes of public health significance are circulating in ground beef sold in the major Mexican city. Some of these strains are multi-drug resistance.

  5. Antibiotic of resistence profile of Salmonella spp. serotypes isolated from retail beef in Mexico City.

    Directory of Open Access Journals (Sweden)

    Nova Nayarit-Ballesteros

    2016-05-01

    Full Text Available Objective. To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. Materials and methods. A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp. The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. Results. We isolated a total of 19 strains of Lomita (6, Derby (4, Senftenberg (2, Javiana and Cannsttat (1 and undeter- mined (5 serotypes. The strains showed a high resistance rate to ampicillin (18/19, carbenicillin (16/19, tetracyclin (13/19, and trimethoprim-sulfamethoxazole (13/19. Multidrug resistance was observed in 14 isolates. Conclusions. Several Salmonella spp. serotypes of public health significance are circulating in ground beef sold in the major Mexican city. Some of these strains are multi-drug resistance.

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

    Science.gov (United States)

    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.

  7. Traffic related deaths in Nuevo Leon, Mexico: causes and associated factors Muertes relacionadas con accidentes viales en Nuevo León, México: causas y factores asociados

    Directory of Open Access Journals (Sweden)

    Carlos Arreola-Rissa

    2008-01-01

    Full Text Available OBJECTIVE: The effects of alcohol on mortality due to motor vehicle accidents was studied. MATERIAL AND METHODS: During the first semester of 2003, a sample of 243 fatality victims of traffic-related accidents and their blood alcohol levels were analyzed in the state of Nuevo Leon, Mexico. The age-adjusted mortality rate for traffic accidents was 8.9/100000 pop. (13.2 for males and 3.21 for females, per 100000. Fatal accidents were more common in the Metropolitan Area (MA. RESULTS: Fatalities were four times greater in males and the mean age was 34.7±18.2 years. Blood alcohol was detected in almost half of the victims who were drivers of the vehicles; the other cases of fatalities may be associated with road/car condition, weather and other factors. CONCLUSIONS: Alcohol intoxication levels were primarily associated with male drivers ages 16 to 45 (p=0.029; levels increased with age. In females, alcohol played a lesser role, affecting mostly ages 31 to 45 y (p=0.055.OBJETIVO:Durante seis meses de 2003 se estudió el efecto del alcohol en 243 víctimas fatales relacionadas con accidentes viales del estado de Nuevo León, México. MATERIAL Y MÉTODOS: Se realizó autopsia en todos los casos y se determinó el nivel de alcohol en sangre. La tasa de mortalidad ajustada por edad para accidentes viales fue 8.9/100000 hab. (13.2 para hombres y 3.21 para mujeres, por 100000. Accidentes fatales fueron comunes en el Área Metropolitana. RESULTADOS: Las fatalidades fueron cuatro veces mayores en hombres y la edad promedio fue de 34.7±18.2 años. Se detectaron niveles de alcohol en sangre en casi la mitad de los conductores que fueron víctimas; los otros casos de fatalidad fueron asociados con las condiciones del camino, el auto, factores meteorológicos, entre otros. CONCLUSIONES: Los niveles de intoxicación alcohólica fueron básicamente con conductores masculinos, de 16-45 años (p=0.029, aumentando con la edad. Entre las mujeres, el alcohol jugó un

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

    Science.gov (United States)

    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.

  9. Border Environmental Education Resource Guide: Southern New Mexico, South Texas, Northern Chihuahua, Northern Coahuila, Northern Nuevo Leon, Northern Tamaulipas = Guia de Recursos de Educacion Ambiental en la Frontera: Sur de Nuevo Mexico, Sur de Texas, Norte de Chihuahua, Norte de Coahuila, Norte de Nuevo Leon, Norte de Tamaulipas.

    Science.gov (United States)

    Meissner, David, Comp.

    This guide provides educators and residents of the border with useful information about environmental education program offerings along the eastern half of the United States-Mexico border. The programs listed in the guide represent a broad range of educational efforts focused on understanding the environment and solving environmental problems in…

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

    Science.gov (United States)

    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.

  11. Guardians of health: the dimensions of elder caregiving among women in a Mexico City neighborhood.

    Science.gov (United States)

    Mendez-Luck, Carolyn A; 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 and 92 years. The relationship of caregiver to care recipient was wife, daughter, daughter-in-law, grand-daughter, sibling, and other relative. The mean length of time providing care was 5 years. Most participants were not employed outside the home, and the median monthly household income was 2000 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.

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

    Science.gov (United States)

    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.

  13. A Pathological Study of the Epidemiology of Atherosclerosis in Mexico City

    Directory of Open Access Journals (Sweden)

    Joel Rodríguez-Saldaña

    2014-01-01

    Full Text Available Objective. To examine the frequency and patterns of association of cardiovascular risk factors with atherosclerosis in five different arterial territories at post-mortem in Mexico City. Methods. We obtained five arterial territories arteries (circle of Willis, coronary, carotid, renal, and aorta of 185 men and women 0 to 90 years of age who underwent autopsy at the Medical Forensic Service of Mexico City. We determined the prevalence and extent of atherosclerotic lesions by histopathology according to the classification of the American Heart Association as early (types I–III and advanced (types IV–VI, and according to the degree of stenosis and correlated with cardiovascular risk factors. Results. Atherosclerotic lesions were identified in at least one arterial territory in 181 subjects (97.8%, with involvement of two ore more territories in 178 subjects (92.2%. Advanced lesions were observed in 36% and 67% of subjects under 15 and between 16 and 35 years, respectively. Any degree of atherosclerosis was associated with the presence of diabetes mellitus, hypertension, overweight, obesity, and smoking, and to a greater extent with the presence of two or more risk factors (P<0.001. However, emerging and advanced athersoclerosis was observed in 53% and 20% people with no risk factors. Conclusions. The study shows a high prevalence of atherosclerosis in all age groups and both sexes. There is considerable development of atherosclerotic disease in subjects without known risk factors.

  14. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Rodolfo Sosa, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Humberto Bravo, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico)], E-mail: hbravo@servidor.unam.mx; Violeta Mugica, A. [Universidad Autonoma Metropolitana, Azcapotzalco, D.F. (Mexico); Pablo Sanchez, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Emma Bueno, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia (Mexico); Krupa, Sagar [Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 (United States)

    2009-03-15

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City.

  15. Clinical characteristics and outcomes of influenza and other influenza-like illnesses in Mexico City.

    Science.gov (United States)

    Galindo-Fraga, Arturo; Ortiz-Hernández, Ana A; Ramírez-Venegas, Alejandra; Vázquez, Rafael Valdez; Moreno-Espinosa, Sarbelio; Llamosas-Gallardo, Beatriz; Pérez-Patrigeon, Santiago; Salinger, Maggie; Freimanis, Laura; Huang, Chiung-yu; Gu, Wenjuan; Guerrero, M Lourdes; Beigel, John; Ruiz-Palacios, Guillermo M

    2013-07-01

    Influenza-like illnesses (ILI) are estimated to cause millions of deaths annually. Despite this disease burden, the etiologic causes of ILI are poorly described for many geographical regions. Beginning in April 2010, we conducted an observational cohort study at five hospitals in Mexico City, enrolling subjects who met the criteria for ILI. Evaluations were conducted at enrollment and on day 28, with the collection of clinical data and a nasopharyngeal swab (or nasal aspirate in children). Swabs were tested by multiplex PCR for 15 viral pathogens and real-time PCR for influenza. During the first year, 1065 subjects were enrolled in this study, 55% of whom were hospitalized; 24% of all subjects were children. One or more pathogens were detected by PCR in 64% of subjects, most commonly rhinovirus (25% of all isolates) and influenza (24% of isolates). Six percent of subjects died, and of those, 54% had no pathogen identified. Rhinovirus was the most common pathogen among those who died, although it did not have the highest case fatality rate. Multiple respiratory viruses beyond influenza are associated with significant morbidity and mortality among adults and children in Mexico City. Detection of these agents could be useful for the adjustment of antibiotic treatment in severe cases. Copyright © 2013 International Society for Infectious Diseases. All rights reserved.

  16. Evaluation of iron overload in healthy adult residents of Mexico City.

    Science.gov (United States)

    Baptista-González, Héctor; Rosenfeld-Mann, Fanny; Trueba-Gómez, Rocío; Méndez-Sánchez, Nahum; Uribe, Misael

    2005-01-01

    We described the effects of age, gender and body mass index (BMI) on the prevalence of iron overload (IO) in blood donors from Mexico City. A cross-sectional study of clinically healthy adults was performed. We evaluated serum ferritin (SF) concentration to allow us to establish groups with normal iron stores (SF >30 microg/L) and with IO (SF >200 microg/L and >300 microg/L for women and men), in the following ages groups: 18-29 years, 30-49 years, and 50-64 years, divided by gender. The study included 1757 subjects. Prevalence of IO was 12% in men and 4.8% in women, and prevalence increased in parallel with increasing age (15.6, 25.0 and 29.9% and 3.5, 5.2 and 9.6%, for men and women, respectively). Regression analysis showed that in men there was a significant association of SF and IO with age, BMI and recent blood donation (p BMI and recent blood donation. IO is highly prevalent in blood donors residing in Mexico City, more so in men than in women. Age, gender and BMI had a positive association with iron stores. This report is the initial contribution towards the study of IO in the Mexican population.

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

    Energy Technology Data Exchange (ETDEWEB)

    Thayer, G.R.; Hardie, R.W. [Los Alamos National Lab., NM (United States); Barrera-Roldan, A. [Instituto Mexicano de Petroleo, Mexico City (Mexico)

    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 linear 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Trends in Microbiological and Antibiotic Sensitivity Patterns in Infectious Keratitis: 10-Year Experience in Mexico City.

    Science.gov (United States)

    Hernandez-Camarena, Julio C; Graue-Hernandez, Enrique O; Ortiz-Casas, Mariana; Ramirez-Miranda, Arturo; Navas, Alejandro; Pedro-Aguilar, Lucero; Lopez-Espinosa, Nadia L; Gaona-Juarez, Carolina; Bautista-Hernandez, Luis A; Bautista-de Lucio, Victor M

    2015-07-01

    To report the distribution and trends in microbiological and antibiotic sensitivity patterns of infectious keratitis in a 10-year period at a reference center in Mexico City. In this retrospective observational case series, samples were obtained from corneas with a diagnosis of infectious keratitis from January 2002 to December 2011 at the Institute of Ophthalmology "Conde de Valenciana" in Mexico City. Results of cultures, stains, and specific sensitivity/resistance antibiograms for each microorganism were analyzed. A total of 1638 consecutive corneal scrapings were analyzed. Pathogen was recovered in 616 samples (38%), with bacterial keratitis accounting for 544 of the positive cultures (88%). A nonsignificant increasing trend in gram-negative isolates (P = 0.11) was observed. The most commonly isolated pathogen was Staphylococcus epidermidis, and the most common gram-negative isolated species was Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 45% of the S. aureus isolates; meanwhile, 53.7% coagulase-negative Staphylococcus isolates were methicillin resistant (MRCNS). Pseudomonas aeruginosa resistance to ceftazidime increased from 15% in the first period to 74% for the last 5 years of the study (P = 0.01). The overall sensitivity for vancomycin of MRSA was 87.5%, whereas 99.6% of the MRCNS were sensitive. There was a nonsignificant increase in the recovered gram-positive and gram-negative microorganisms over time. We observed an increased resistance to methicillin in almost half of the MRSA and MRCNS isolates.

  1. A Pathological Study of the Epidemiology of Atherosclerosis in Mexico City

    Science.gov (United States)

    Rodríguez-Saldaña, Joel; Rodriguez-Flores, Marcela; Cantú-Brito, Carlos; Aguirre-Garcia, Jesús

    2014-01-01

    Objective. To examine the frequency and patterns of association of cardiovascular risk factors with atherosclerosis in five different arterial territories at post-mortem in Mexico City. Methods. We obtained five arterial territories arteries (circle of Willis, coronary, carotid, renal, and aorta) of 185 men and women 0 to 90 years of age who underwent autopsy at the Medical Forensic Service of Mexico City. We determined the prevalence and extent of atherosclerotic lesions by histopathology according to the classification of the American Heart Association as early (types I–III) and advanced (types IV–VI), and according to the degree of stenosis and correlated with cardiovascular risk factors. Results. Atherosclerotic lesions were identified in at least one arterial territory in 181 subjects (97.8%), with involvement of two ore more territories in 178 subjects (92.2%). Advanced lesions were observed in 36% and 67% of subjects under 15 and between 16 and 35 years, respectively. Any degree of atherosclerosis was associated with the presence of diabetes mellitus, hypertension, overweight, obesity, and smoking, and to a greater extent with the presence of two or more risk factors (P < 0.001). However, emerging and advanced athersoclerosis was observed in 53% and 20% people with no risk factors. Conclusions. The study shows a high prevalence of atherosclerosis in all age groups and both sexes. There is considerable development of atherosclerotic disease in subjects without known risk factors. PMID:24719773

  2. Acute Appendicitis After Kidney Transplantation: Experience at a Tertiary Care Hospital in Mexico City.

    Science.gov (United States)

    Ortiz-Brizuela, Edgar; Quiroz-Compeán, Alejandro; Vilatobá-Chapa, Mario; Alberú-Gómez, Josefina

    2018-04-01

    Here, we describe the presentation, treatment, and outcomes of acute appendicitis in kidney transplant recipients at a tertiary care hospital in Mexico City. We conducted a retrospective case series study at a tertiary care hospital in Mexico City from January 2000 to January 2015. During our study period, 1186 patients received a kidney transplant; among these patients, we identified 10 cases of acute appendicitis (0.008%). Four patients (40%) were diagnosed on day 5 of symptom onset. Nine patients (90%) showed abdominal pain, 2 patients (20%) presented with a typical migratory pattern, and 2 patients (20%) showed symptoms of small bowel intestinal obstruction. Thirty percent of patients (3/10) presented a rule-out Alvarado score (≤ 3 points). A computed tomography scan was performed in all but one patient; among these 9 patients, 1 (11.1%) had a false-negative result. Among all patients with acute appendicitis, 50% (5/10) presented with a periappendiceal abscess and 40% (4/10) showed localized peritonitis. An open and laparoscopic appendectomy was performed in 7 of 10 patients (70%) and 3 of 10 patients (30%), respectively. All patients received ceftriaxone plus metronidazole or ertapenem for 5 to 7 days. There were no reported treatment failures or recurrence of symptoms. The diagnosis of acute appendicitis in kidney transplant recipients requires a high index of suspicion. Kidney transplant recipients with acute appendicitis had good outcomes with a therapeutic approach similar to that used in the general population.

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

    International Nuclear Information System (INIS)

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

    1993-01-01

    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 linear function of the reduction of hydrocarbon and NO 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 x . The relationship between ozone levels and the hydrocarbon and NO 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

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

    Science.gov (United States)

    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.

  5. Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign

    Directory of Open Access Journals (Sweden)

    P. F. DeCarlo

    2008-07-01

    Full Text Available The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1 was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA and biomass burning (BB are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m−3 (STP ppm−1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006 and Kleinman et al. (2008. The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance

  6. Mexico.

    Science.gov (United States)

    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,…

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    L. T. Molina

    2010-09-01

    Full Text Available 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

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

    Science.gov (United States)

    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

  12. Aerosol effects on the photochemistry in Mexico City during MCMA-2006/MILAGRO campaign

    Directory of Open Access Journals (Sweden)

    G. Li

    2011-06-01

    Full Text Available In the present study, the impact of aerosols on the photochemistry in Mexico City is evaluated using the WRF-CHEM model for the period from 24 to 29 March during the MCMA-2006/MILAGRO campaign. An aerosol radiative module has been developed with detailed consideration of aerosol size, composition, and mixing. The module has been coupled into the WRF-CHEM model to calculate the aerosol optical properties, including optical depth, single scattering albedo, and asymmetry factor. Calculated aerosol optical properties are in good agreement with the surface observations and aircraft and satellite measurements during daytime. In general, the photolysis rates are reduced due to the absorption by carbonaceous aerosols, particularly in the early morning and late afternoon hours with a long aerosol optical path. However, with the growth of aerosol particles and the decrease of the solar zenith angle around noontime, aerosols can slightly enhance photolysis rates when ultraviolet (UV radiation scattering dominates UV absorption by aerosols at the lower-most model layer. The changes in photolysis rates due to aerosols lead to about 2–17 % surface ozone reduction during daytime in the urban area in Mexico City with generally larger reductions during early morning hours near the city center, resulting in a decrease of OH level by about 9 %, as well as a decrease in the daytime concentrations of nitrate and secondary organic aerosols by 5–6 % on average. In addition, the rapid aging of black carbon aerosols and the enhanced absorption of UV radiation by organic aerosols contribute substantially to the reduction of photolysis rates.

  13. Chemically-resolved aerosol eddy covariance flux measurements in urban Mexico City during MILAGRO 2006

    Science.gov (United States)

    Zalakeviciute, R.; Alexander, M. L.; Allwine, E.; Jimenez, J. L.; Jobson, B. T.; Molina, L. T.; Nemitz, E.; Pressley, S. N.; VanReken, T. M.; Ulbrich, I. M.; Velasco, E.; Lamb, B. K.

    2012-08-01

    As part of the MILAGRO 2006 field campaign, the exchange of atmospheric aerosols with the urban landscape was measured from a tall tower erected in a heavily populated neighborhood of Mexico City. Urban submicron aerosol fluxes were measured using an eddy covariance method with a quadrupole aerosol mass spectrometer during a two week period in March, 2006. Nitrate and ammonium aerosol concentrations were elevated at this location near the city center compared to measurements at other urban sites. Significant downward fluxes of nitrate aerosol, averaging -0.2 μg m-2 s-1, were measured during daytime. The urban surface was not a significant source of sulfate aerosols. The measurements also showed that primary organic aerosol fluxes, approximated by hydrocarbon-like organic aerosols (HOA), displayed diurnal patterns similar to CO2 fluxes and anthropogenic urban activities. Overall, 47% of submicron organic aerosol emissions were HOA, 35% were oxygenated (OOA) and 18% were associated with biomass burning (BBOA). Organic aerosol fluxes were bi-directional, but on average HOA fluxes were 0.1 μg m-2 s-1, OOA fluxes were -0.03 μg m-2 s-1, and BBOA fluxes were -0.03 μg m-2 s-1. After accounting for size differences (PM1 vs PM2.5) and using an estimate of the black carbon component, comparison of the flux measurements with the 2006 gridded emissions inventory of Mexico City, showed that the daily-averaged total PM emission rates were essentially identical for the emission inventory and the flux measurements. However, the emission inventory included dust and metal particulate contributions, which were not included in the flux measurements. As a result, it appears that the inventory underestimates overall PM emissions for this location.

  14. A Methodological Approach to the Study of Urban Memory: Narratives about Mexico City

    Directory of Open Access Journals (Sweden)

    Martha de Alba

    2012-05-01

    Full Text Available This article serves a dual purpose. On the one hand, I seek to understand social representations and the collective memory of a sample of older adults, resident in the metropolitan area of Mexico City. On the other hand, I wish to reflect on the methodology used to achieve that objective, placing special emphasis on the combination of two complementary techniques: Atlas.ti, a tool used to carry out a semantic analysis of the interviews, and Alceste, a program that makes it possible to observe a classification of the terms used by respondents based on a statistical analysis of co-occurrences. The article is structured in the following order. Firstly, I explain the theoretical presuppositions that sustain the study. Secondly, I look at the methodology used, the reasons why I decided to use the software in question, and the analysis strategies for the interviews. Finally, I present the results obtained, and close with a final discussion on the relevance of the general methodology of the study for analyzing urban memory. The results indicate different levels of analysis of extensive narratives about the past experience of a great city like Mexico City; from the individual level that allows Atlas.ti up to a collective level (gender differences, location or socioeconomic status that prioritizes Alceste. I discuss the limitations of these software tools to analyze experiences that have continuity in time and space, as well in the incorporation of space as a complex category of analysis. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1202276

  15. Uranium hydrogeochemical and stream sediment reconnaissance data release for the New Mexico portions of the Douglas, Silver City, Clifton, and Saint Johns NTMS quadrangles, New Mexico/Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, R.R. Jr.; Morris, W.A.; Aamodt, P.L.

    1978-03-01

    This report describes work done in the Douglas, Silver City, Clifton, and Saint Johns, New Mexico/Arizona, National Topographic Map Series (NTMS) quadrangles (1:250,000 scale) by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). The HSSR is designed to identify areas having higher-than-normal concentrations of uranium in ground waters, surface waters, and water-transported sediments. In 1976 three private contractors, under contract to the LASL, collected water and stream sediment samples in New Mexico from the Mexico border north to Interstate 40 (north of 35/sup 0/N latitude) and from 107/sup 0/30' W longitude west to the New Mexico/Arizona state line. This report presents only the data from these sampling programs for the locations west of 108/sup 0/W longitude--the New Mexico portions of the Douglas, Silver City, Clifton, and Saint Johns NTMS quadrangles. The numbers of water samples and sediment samples, respectively, collected in each quadrangle were: Douglas, 181 and 237; Silver City, 474 and 755; Clifton, 469 and 913; and Saint Johns, 437 and 672. The standard field and analytical procedures used in this uranium reconnaissance are given in Appendix A. Listings of the field and uranium data for the water samples from the New Mexico portions of the four NTMS quadrangles are given in Appendixes B-I through B-IV. Listings of the field and uranium data for the sediment samples are given in Appendixes C-I through C-IV. Keys to the water and sediment sample types as well as codes to site data are given in Appendix D.

  16. Uranium hydrogeochemical and stream sediment reconnaissance data release for the New Mexico portions of the Douglas, Silver City, Clifton, and Saint Johns NTMS quadrangles, New Mexico/Arizona

    International Nuclear Information System (INIS)

    Sharp, R.R. Jr.; Morris, W.A.; Aamodt, P.L.

    1978-03-01

    This report describes work done in the Douglas, Silver City, Clifton, and Saint Johns, New Mexico/Arizona, National Topographic Map Series (NTMS) quadrangles (1:250,000 scale) by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). The HSSR is designed to identify areas having higher-than-normal concentrations of uranium in ground waters, surface waters, and water-transported sediments. In 1976 three private contractors, under contract to the LASL, collected water and stream sediment samples in New Mexico from the Mexico border north to Interstate 40 (north of 35 0 N latitude) and from 107 0 30' W longitude west to the New Mexico/Arizona state line. This report presents only the data from these sampling programs for the locations west of 108 0 W longitude--the New Mexico portions of the Douglas, Silver City, Clifton, and Saint Johns NTMS quadrangles. The numbers of water samples and sediment samples, respectively, collected in each quadrangle were: Douglas, 181 and 237; Silver City, 474 and 755; Clifton, 469 and 913; and Saint Johns, 437 and 672. The standard field and analytical procedures used in this uranium reconnaissance are given in Appendix A. Listings of the field and uranium data for the water samples from the New Mexico portions of the four NTMS quadrangles are given in Appendixes B-I through B-IV. Listings of the field and uranium data for the sediment samples are given in Appendixes C-I through C-IV. Keys to the water and sediment sample types as well as codes to site data are given in Appendix D

  17. Atmospheric electric field effects of cosmic rays detected in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, L. X; Valdes-Galicia, J. F [Instituto de Geofisica, Universidad National Autonoma de Mexico, Mexico D.F(Mexico)

    2006-10-15

    We studied the possible effects of atmospheric electric fields, generated in thunderstorms, on the cosmic ray intensity detected at the Earth's surface by investigating the variations of the counting rates of the cosmic-ray nucleonic component, obtained from the neutron monitor installed in Mexico City, for thunderstorms during 1996 and 1997. These were years of minimum solar activity. We compare our experimental results with the general theory of cosmic ray meteorological effects by Dorman (1995). The observed intensity variation is about 0.2%. According to Dorman (1995), the effect should be between 0.27% and 0.81% on the counting rate of the neutron monitor when the atmospheric electric field intensities are around 100 to 300 Vcm-1.Our results show that either the electric field in Mexico City had less intensity than assumed by Dorman (1995), or the electric field is not uniform in time and height during the development of the thunderstorm. [Spanish] Estudiamos los posibles efectos de los campos electricos atmosfericos, generados en las tormentas electricas, sobre la intensidad de los rayos cosmicos detectados en la superficie terrestre, analizando las variaciones de las razones de conteo de la componente nucleonica de los rayos cosmicos, obtenidas por el monitor de neutrones instalado en la ciudad de Mexico, durante tormentas electricas ocurridas entre 1996 y 1997, anos del minimo solar. Comparamos nuestros resultados experimentales con la teoria general de los efectos meteorologicos en los rayos cosmicos, desarrollada por Dorman (1995). Se observo una variacion en la intensidad de alrededor de 0.2%. De acuerdo con Dorman (1995), el efecto puede estar entre 0.27 % y 0.81% en las razones de conteo del monitor de neutrones cuando las intensidades del campo electrico atmosferico se encuentran al rededor de 100 a 300 Vcm-1. Nuestros resultados muestran que los campos electricos en la ciudad de Mexico tuvieron menos intensidad que los campos electricos asumidos

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Resistance of uropathogenic bacteria to first-line antibiotics in mexico city: A multicenter susceptibility analysis.

    Science.gov (United States)

    Arredondo-García, José Luis; Soriano-Becerril, Diana; Solórzano-Santos, Fortino; Arbo-Sosa, Antonio; Coria-Jiménez, Rafael; Arzate-Barbosa, Patricia

    2007-03-01

    Abstract. Growing antibiotic resistance demands the constant reassessment of antimicrobial efficacy, particularly in countries with wide antibiotic abuse, where higher resistance prevalence is often found. Knowledge of resistance trends is particularly important when prescribing antibiotics empirically, as is usually the case for urinary tract infections (UTIs). Currently, in Mexico City, ampicillin, cotrimoxazole (trimethoprim/sulfamethoxazole), and ciprofloxacin are used as "first-line" antibiotic treatment for UTI. The aim of this study was to analyze the resistance of bacterial isolates to antibiotics, with a focus on first-line antibiotics, in Mexican pediatric patients and sexually active or pregnant female outpatients. In this multicenter susceptibility analysis, bacterial isolates from urine samples collected from pediatric patients and sexually-active or pregnant female outpatients presenting with acute, uncomplicated UTIs in Mexico City from January 2006 through June 2006, were included in the study. Samples were tested for susceptibility to 10 antibiotics by the disk-diffusion method. Four-hundred and seventeen bacterial isolates were derived from sexually active or pregnant female outpatients (324 Escherichia coli) and pediatric patients (93 Klebsiella pneumoniae). We found a high prevalence of resistance towards the drugs used as "first-line" when treating UTIs: ampicillin, cotrimoxazole, and ciprofloxacin (79%, 60%, and 24% resistance, respectively). Ninety-eight percent of K pneumoniae isolates were resistant to ampicillin, whereas 66% of the E coli isolates were resistant to cotrimoxazole. Resistance towards third-generation cephalosporins was also high (6%-8% of E coli and 10%-28% of K pneumoniae). This was possibly caused by chromosomal β-lactamases, as 30% of all isolates were also resistant to amoxicillin/clavulanate. In contrast, 98% of the E coli isolates and 84% of the K pneumoniae strains (96% of all isolates) were found to be susceptible

  1. Investigation of the correlation between odd oxygen and secondary organic aerosol in Mexico City and Houston

    Directory of Open Access Journals (Sweden)

    E. C. Wood

    2010-09-01

    Full Text Available Many recent models underpredict secondary organic aerosol (SOA particulate matter (PM concentrations in polluted regions, indicating serious deficiencies in the models' chemical mechanisms and/or missing SOA precursors. Since tropospheric photochemical ozone production is much better understood, we investigate the correlation of odd-oxygen ([Ox]≡[O3]+[NO2] and the oxygenated component of organic aerosol (OOA, which is interpreted as a surrogate for SOA. OOA and Ox measured in Mexico City in 2006 and Houston in 2000 were well correlated in air masses where both species were formed on similar timescales (less than 8 h and not well correlated when their formation timescales or location differed greatly. When correlated, the ratio of these two species ranged from 30 μg m−3/ppm (STP in Houston during time periods affected by large petrochemical plant emissions to as high as 160 μg m−3/ppm in Mexico City, where typical values were near 120 μg m−3/ppm. On several days in Mexico City, the [OOA]/[Ox] ratio decreased by a factor of ~2 between 08:00 and 13:00 local time. This decrease is only partially attributable to evaporation of the least oxidized and most volatile components of OOA; differences in the diurnal emission trends and timescales for photochemical processing of SOA precursors compared to ozone precursors also likely contribute to the observed decrease. The extent of OOA oxidation increased with photochemical aging. Calculations of the ratio of the SOA formation rate to the Ox production rate using ambient VOC measurements and traditional laboratory SOA yields are lower than the observed [OOA]/[Ox] ratios by factors of 5 to 15, consistent with several other models' underestimates of SOA. Calculations of this ratio using emission factors for organic compounds from gasoline and diesel exhaust do not reproduce the observed

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.…

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

    Science.gov (United States)

    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…

  6. Concentration levels of radon in air, indoors and outdoors in houses of Mexico City

    International Nuclear Information System (INIS)

    Pena Garcia, P.

    1992-01-01

    Concentration levels of radon in air, indoors and outdoors have been obtained in houses from Mexico City, with the purpose of relating them with the local environment. Measurements were performed both outdoors and indoors in 60 unifamiliar houses. Track detectors, LR-115, Type II, were used in several detection arrangements during four recording periods with times of exposure of three months each, with the purpose of analyzing the fluctuations due to seasonal changes. Data were obtained about the construction materials were the detection systems were located in order to establish a correlation of radon levels with the climatic parameters and the construction materials. The results of radon concentrations both indoors or outdoors were lower than the international recommendations (148 Bq/m 3 ) (Author)

  7. The Displacement of the Possible: Popular Experience and Gentrification at Historic Center of Mexico City

    Directory of Open Access Journals (Sweden)

    Vicente Moctezuma Mendoza

    2016-09-01

    Full Text Available This paper studies the displacement of popular sectors in the Historic Center of Mexico City as part of the gentrification process in this space. Particularly, it analyzes a form of displacement that the author defines as ‘the displacement in popular horizons of the possible’, and supposes a reinterpretation – from the characteristics of the gentrification processes in Latin America and the anthropologic fieldwork- of the definition of ‘exclusionary displacement’ proposed by Peter Marcuse. Displacement is analyzed through an ethnographic approach to some residential itineraries that account for popular sectors different rooting constructions during the second half of the twentieth century and the review of the permanence or disappearance of such conditions in the contemporary context.

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

    Science.gov (United States)

    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.

  9. SURVIVAL STRATEGIES OF MICROENTREPRENEURS IN SOUTHERN MEXICO CITY: INFLUENCE OF APPRECIATED LEARNING

    Directory of Open Access Journals (Sweden)

    Arcelia López-Cabello

    2015-07-01

    Full Text Available The strategies of family reproduction are various ways in which families cope with the problems of everyday life, where the preservation of life and development of essential economic practices is ensured to optimize the material and non-material conditions of the family unit and of each of its members. Through in-depth interviews it was learned how some microentrepreneurs in Mexico City, have used their knowledge appreciated to implement various business generates economic resources to survive, but also have inherited the children. Technical and family secrets on how to make some product knowledge are transmitted from generation to generation, and part of the heritage of a family, becoming livelihood strategies.

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

    Science.gov (United States)

    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.

  11. Gender performativity, medicalization and health in transsexual women in Mexico City

    Directory of Open Access Journals (Sweden)

    José Arturo Granados Cosme

    2017-12-01

    Full Text Available 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.

  12. Stress from an administrative perspective in public transport drivers in Mexico City: Minibus and metrobus

    Directory of Open Access Journals (Sweden)

    Fernando Lámbarry

    2016-04-01

    Full Text Available Stress is one of the occupational diseases that affect workers worldwide, affecting their own productivity and performance (as well as that of the organizations where they work, and even their physical and mental health. According to the International Labour Organization, Mexican workers suffer from stress the most all over the world, since theirs is one of the most stressful professions. With this in mind, the aim of this research is to study the work stress in bus rapid transit drivers and minibus in Mexico City. The method used is based on an exploratory statistical factorial analysis. It is concluded that the factors which a higher influence in the onset of stress are organizational, environmental (physical/individual, inherent to the position, extra organizational and individual. Although divergent among drivers, minibus drivers are the workers who suffer the most from stress.

  13. Air pollution problem in the Mexico City metropolitan zone: Photochemical pollution

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, H.B.; Alvarez, P.S.; Echeverria, R.S.; Jardon, R.T. [Centro de Ciencias de la Atmosfera (Mexico). Seccion de Contaminacion Ambiental

    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, ozone 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.

  14. An Approach to Litter Generation and Littering Practices in a Mexico City Neighborhood

    Directory of Open Access Journals (Sweden)

    Cecilia E. Muñoz-Cadena

    2012-08-01

    Full Text Available Urban litter is generated by human societies everywhere. Some litter is recyclable waste. In this study, the acronym RMSW is used to refer to recyclable municipal solid waste generated in streets. Public attitude towards RMSW generation, generators’ perceptions, and quantification of RMSW in streets were examined in a Mexico City neighborhood, where litter presence causes major environmental problems affecting the population year after year. Interviews with neighborhood residents and item counts were carried out from 2010 to 2011. In all, 58% of interviewees reported generating RMSW at variable frequencies while 42% said they did not generate this kind of waste. Laziness, lack of vigilance by municipal authorities, no litter bins in streets, and imitation were the main causes identified by interviewees as reasons for littering. Potential litter generators may be of any age, educational level or income. Interviewees’ perception of RMSW generation was compared with item counts in the neighborhood studied.

  15. Soil contamination by Toxocara spp. eggs in a university in Mexico City.

    Science.gov (United States)

    Trejo, Carlos Antelmo Celis; Romero Núñez, Camilo; García Contreras, Adelfa Del Carmen; Mendoza Barrera, Germán Eduardo

    2012-01-01

    The contamination levels of Toxocara spp. eggs in soil samples from a university campus in Mexico City were evaluated and analysed according to garden size, and were related with the percentage of Toxocara spp. eggs and its viability according to the soil characteristics. A total of 1458 soil samples collected in 15 gardens (six large and nine small) were analysed by sedimentation-flotation with zinc sulphate solution on at 33%. Contamination was low (12.9%), and egg viability was high (65.5%). The size of the garden had no influence on the presence and viability of Toxocara spp. eggs. Contamination was negatively correlated with the percentage of vegetation (r = -0. 61, P soil samples (r = -0.51, P < 0.04). The size of the garden did not influence the presence and viability of Toxocara spp. eggs.

  16. Comparison of NO2 and HCHO Vertical Columns Over Mexico City from Ground and Space

    Science.gov (United States)

    Ojeda Lerma, Z.; Grutter, M.; Stremme, W.; Rivera, C.; Friedrich, M. M.; Bezanilla Morlot, A.

    2017-12-01

    Here we present the analysis of spectra measured by the MAX-DOAS (Multi Axis Differential Optical Absorption Spectroscopy) instruments, wich form part of a monitoring network located in the Mexico City Metropolitan Area (MCMA). The spectra are processed using the MMF (Mexican Maxdoas Fit) retrieval code which is based on least square fitting and uses optimal estimation and Tikhonov regularization for trace gas and aerosol retrieval, respectively. The retrieved vertical columns densities of NO2 and the methodology used for the statistical calculation of the errors are presented. We compare the NO2 vertical columns densities from the MAX-DOAS measurements with the tropospheric vertical columns from the OMI (Ozone Monitoring Instrument) satellite sensor, using both the DOMINO (Dutch OMI NO2) and the Standard Products V003. The variability observed in the time series of NO2 and HCHO are anlyzed in terms of known patterns of the emission sources, photochemistry and seasonality.

  17. Two year study of elemental composition of atmospheric aerosols in Mexico City

    International Nuclear Information System (INIS)

    Aldape, F.; Flores, J.; Diaz, R.V.; Miranda, J.; Cahill, T.A.; Morales, J.R.

    1991-01-01

    As the second part of a wide project, we have carried out a study of airborne particulates in Mexico City, collected during two time periods (from 7:00 to 11:00, and from 11:00 to 15:00 Hrs.), one day of every week between March 1988 and February 1990. Elemental concentrations were determined by Proton Induced X-ray Emission (PIXE) for elements Na to Pb, while soot content was measured by means of Laser Integrating Plate Method (LIPM). As expected, the concentrations show an increase during the months October to March, due to frequent thermal inversions and dry weather. Moreover, the pollutant levels are higher during earlier hours, while the soil and anthropogenic origin of the elements can be better determined for the mid-day period, as seen from the grouping in the respective dendrograms. (author)

  18. Genetic variation of 17 STR loci in a Mexican Mestizo population from Mexico City.

    Science.gov (United States)

    Saiz, Maria; Rios-Rivas, Ricardo Jesús; Alvarez, Juan Carlos; Lorente, José Antonio; Villegas-Carmona, Dora; Ramirez-Flores, Erika; Vega-Navarrete, Lourdes

    2016-11-01

    Genetic data from 17 autosomal short tandem repeat (STR) loci found in the Powerplex® ESX 17 System (Promega, Madison, WI, USA) was evaluated in 162 unrelated Mexican Mestizo individuals from Mexico City. Allele frequencies and forensic parameters were estimated for the 17 STRs. All loci analyzed were in Hardy-Weinberg equilibrium in the studied population and showed not any signs of linkage between loci. The combined power of discrimination and the power of exclusion for the 16 aSTRs studied were 1-2.56409·10 -19 and 99.999938 %, respectively. Genetic distances reveal a close relationship within different populations of Mexican Mestizos. The obtained data might be useful for population genetics research and for individual identification and paternity testing in forensic science.

  19. Blood lead levels in pregnant women of high and low socioeconomic status in Mexico City.

    Science.gov (United States)

    Farias, P; Borja-Aburto, V H; Rios, C; Hertz-Picciotto, I; Rojas-Lopez, M; Chavez-Ayala, R

    1996-10-01

    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 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 socioeconomic status.

  20. Crisis, Xenophobia and Repatriation. The Spanish Immigrants in the City of Mexico, 1910-1936

    Directory of Open Access Journals (Sweden)

    Alicia GIL LÁZARO

    2011-05-01

    Full Text Available The article deals with the influence of economic crisis in migrant groups. It starts with a reflection about the current situation, putting forward a comparative view with a study case in the past, that is, the circumstances around the Spanish immigrants in Mexico City at the time of Mexican Revolution until the crisis of the Great Depression (1910-1936. Three aspects are explored: first of all, the close relationship between the spreading of the economic crisis and the increase of restrains in migratory public policies in host countries. Secondly, the concomitant growth of xenophobic attitudes in native populations and, finally, the return to the homeland as one of the essential strategies developed by immigrants to confront the crisis drawing upon the social and associative networks of migration movements.

  1. Classification and Geochemical Characterization of Igneous Rocks: Southern Part of Chihuahua City, Mexico

    Science.gov (United States)

    Fontes, I. D.; Espejel-Garcia, V. V.; Villalobos-Aragon, A.

    2013-05-01

    Chihuahua City is the capital of the state with the same name, located in northern Mexico. The city was established near the Chuviscar River, but in the last decades it has been extended to the nearby areas (mountains), with volcanic (rhyolitic tuffs), and sedimentary rocks (limestone). The study area includes areas in the south part of Chihuahua City, where we can still find unbuilt lands and it is possible to appreciate outcrops of igneous rocks. This project includes 5 study spots, which are located about 9 km. far from the south extreme of the city. This research is developed in order to complement the geological information in this area, as there is no is detailed record of it. In the geological map H13-10 (SGM, 1997), it is said that the urban area is covered by Quaternary conglomerates, while exploring the region we have located several igneous rocks outcrops. In three of the sampling points, dark colored intrusive igneous rocks with large crystals appear in blocks without noticeable fractures. While in the other two sampling points, highly fractured blocks of pink aphanitic igneous rocks, showing traces of pyrolusite were observed. The petrographic study shows the two different textures that classify these rocks as extrusive (aphanitic) or intrusive (phaneritic), both with quartz and feldspars being the dominant minerals. Geochemical analyses confirm the felsic composition of the rocks, varying form trachytes to rhyolites. The trace element results show high contents of Sr, Ba, V, Rb, and Zr in trachytic compositions, while there are high concentrations of Mn, W, Rb and Co for rhyolitic compositions.

  2. Organization of a third-level care hospital in Mexico City during the 2009 influenza epidemic.

    Science.gov (United States)

    Bourlon, María T; Macias, Alejandro E; de la Torre, Alethse; Gulias-Herrero, Alfonso; Leal, Patricia E; Domínguez-Cherit, Guillermo; Huertas, Martha; Ruiz-Palacios, Guillermo M

    2009-11-01

    An outbreak caused by the novel swine-origin influenza A (H1N1) virus was identified in Mexico in late March 2009. The objective of this report is to describe the organization of a tertiary care center in Mexico City during the contingency. We describe the education program, the hospital organization and triaging, and unforeseen overwhelming circumstances. Educational plans were directed to follow standard, contact, and droplet precautions and to condition behavior to avoid touching the eyes, nose, or mouth. N95 respirators were distributed only to perform respiratory procedures. By the fifth month into the epidemic, four patients with hospital-acquired influenza, 467 workers with respiratory symptoms suggestive of influenza (16% of our staff), and 96 workers with confirmed novel influenza A (3% of our staff) were identified. During the first 2 months of the epidemic, 44,225 people went through the triages and only 1503 (3.3%) reached the emergency room. By the fifth month into the epidemic, four small institutional influenza outbreaks (influenza was used mainly for epidemiological purposes. Even though we had a supply, we had difficulties in meeting the demand of masks, N-95 respirators, and hand sanitizers. Due to absenteeism, the nursing administration experienced difficulties in covering shifts. Preparation is mandatory for facing an influenza epidemic. The correct use of precautions is an economic measure to limit institutional transmission. Adequate triaging is essential to meet unusual attention demands.

  3. Dietary intake, lung function and airway inflammation in Mexico City school children exposed to air pollutants

    Directory of Open Access Journals (Sweden)

    Díaz-Sánchez David

    2009-12-01

    Full Text Available Abstract Introduction Air pollutant exposure has been associated with an increase in inflammatory markers and a decline in lung function in asthmatic children. Several studies suggest that dietary intake of fruits and vegetables might modify the adverse effect of air pollutants. Methods A total of 158 asthmatic children recruited at the Children's Hospital of Mexico and 50 non-asthmatic children were followed for 22 weeks. Pulmonary function was measured and nasal lavage collected and analyzed every 2 weeks. Dietary intake was evaluated using a 108-item food frequency questionnaire and a fruit and vegetable index (FVI and a Mediterranean diet index (MDI were constructed. The impact of these indices on lung function and interleukin-8 (IL-8 and their interaction with air pollutants were determined using mixed regression models with random intercept and random slope. Results FVI was inversely related to IL-8 levels in nasal lavage (p 1 (test for trend p 1 and FVC as was with MDI and ozone for FVC. No effect of diet was observed among healthy children. Conclusion Our results suggest that fruit and vegetable intake and close adherence to the Mediterranean diet have a beneficial effect on inflammatory response and lung function in asthmatic children living in Mexico City.

  4. Spanish Professionals in Mexico City: Narratives on Work and Labour Markets

    Directory of Open Access Journals (Sweden)

    Cristóbal Mendoza

    2008-12-01

    Full Text Available Using qualitative information, this paper studies the labour experiences of a group of skilled Spanish migrants in Mexico City. The paper identifies two types of migrants amongst the interviewed Spaniards: TNCs transferees and “migrants in the middle” (“those who are neither low-skilled migrants nor high-skilled migrants”; Conradson and Latham, 2005a. This somehow challenges assumptions about skilled workers, by showing the multiple work trajectories and experiences of highly qualified and educated workers. The article also stresses that the labour mobility of those in the middle is more horizontal and less conventional than the more typical career-path mobility of TNCs transferees. Furthermore, it is argued that labour mobility is not only related to educational background or performance in Mexico’s labour markets, but also to non-economic reasons (e.g. extensive use of social networks. Of special interest for this study are relations at the workplace as they represent a “contact zone” where “difference” is constantly encountered and negotiated (Yeoh and Willis, 2005b. For the interviewed Spaniards, workplace relations are substantially (and unexpectedly different from those in their home country. This causes tension and problems that may affect their intentions to remain in Mexico.

  5. Dietary intake, lung function and airway inflammation in Mexico City school children exposed to air pollutants.

    Science.gov (United States)

    Romieu, Isabelle; Barraza-Villarreal, Albino; Escamilla-Núñez, Consuelo; Texcalac-Sangrador, Jose L; Hernandez-Cadena, Leticia; Díaz-Sánchez, David; De Batlle, Jordi; Del Rio-Navarro, Blanca E

    2009-12-10

    Air pollutant exposure has been associated with an increase in inflammatory markers and a decline in lung function in asthmatic children. Several studies suggest that dietary intake of fruits and vegetables might modify the adverse effect of air pollutants. A total of 158 asthmatic children recruited at the Children's Hospital of Mexico and 50 non-asthmatic children were followed for 22 weeks. Pulmonary function was measured and nasal lavage collected and analyzed every 2 weeks. Dietary intake was evaluated using a 108-item food frequency questionnaire and a fruit and vegetable index (FVI) and a Mediterranean diet index (MDI) were constructed. The impact of these indices on lung function and interleukin-8 (IL-8) and their interaction with air pollutants were determined using mixed regression models with random intercept and random slope. FVI was inversely related to IL-8 levels in nasal lavage (p diet was observed among healthy children. Our results suggest that fruit and vegetable intake and close adherence to the Mediterranean diet have a beneficial effect on inflammatory response and lung function in asthmatic children living in Mexico City.

  6. Linear and regressive stochastic models for prediction of daily maximum ozone values at Mexico City atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, J. L [Instituto de Geofisica, UNAM, Mexico, D.F. (Mexico); Nava, M. M [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Gay, C [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico)

    2001-07-01

    We developed a procedure to forecast, with 2 or 3 hours, the daily maximum of surface ozone concentrations. It involves the adjustment of Autoregressive Integrated and Moving Average (ARIMA) models to daily ozone maximum concentrations at 10 monitoring atmospheric stations in Mexico City during one-year period. A one-day forecast is made and it is adjusted with the meteorological and solar radiation information acquired during the first 3 hours before the occurrence of the maximum value. The relative importance for forecasting of the history of the process and of meteorological conditions is evaluated. Finally an estimate of the daily probability of exceeding a given ozone level is made. [Spanish] Se aplica un procedimiento basado en la metodologia conocida como ARIMA, para predecir, con 2 o 3 horas de anticipacion, el valor maximo de la concentracion diaria de ozono. Esta basado en el calculo de autorregresiones y promedios moviles aplicados a los valores maximos de ozono superficial provenientes de 10 estaciones de monitoreo atmosferico en la Ciudad de Mexico y obtenidos durante un ano de muestreo. El pronostico para un dia se ajusta con la informacion meteorologica y de radiacion solar correspondiente a un periodo que antecede con al menos tres horas la ocurrencia esperada del valor maximo. Se compara la importancia relativa de la historia del proceso y de las condiciones meteorologicas previas para el pronostico. Finalmente se estima la probabilidad diaria de que un nivel normativo o preestablecido para contingencias de ozono sea rebasado.

  7. Mass movement processes triggered by land subsidence in Iztapalapa, the eastern part of Mexico City

    Directory of Open Access Journals (Sweden)

    M. González-Hernández

    2015-11-01

    Full Text Available Geological and structural conditions in the Basin of Mexico coupled with natural and anthropogenic factors, such as groundwater exploitation, provokes land subsidence and differential deformation. The study area is located in to the north of Iztapalapa, a municipality within Mexico City, in a site called "El Eden" with irregular topography. Where volcanic sequences overlie the lacustrine deposits of clays and silts and show displacements by the action of gravity. The displacement zone was delimited at the top of the slope by the formation of circular tensile fractures with stair -shaped geometries. At the base of the slope, compressive processes damaged housing, sidewalks and inclined light poles and trees. A NW-SE system of fractures was identified in which displacement velocities vary from a few millimeters to several centimeters per year. Which affects urban facilities. In this work a conceptual model of deformation is presented that integrates the geological and mechanical factors leading to landslide and land subsidence. A geophysical survey leads to evidence of how land subsidence processes increase the sliding slope.

  8. Mass movement processes triggered by land subsidence in Iztapalapa, the eastern part of Mexico City

    Science.gov (United States)

    González-Hernández, M.; Carreón-Freyre, D.; Gutierrez-Calderon, R.; Cerca, M.; Flores-Garcia, W.

    2015-11-01

    Geological and structural conditions in the Basin of Mexico coupled with natural and anthropogenic factors, such as groundwater exploitation, provokes land subsidence and differential deformation. The study area is located in to the north of Iztapalapa, a municipality within Mexico City, in a site called "El Eden" with irregular topography. Where volcanic sequences overlie the lacustrine deposits of clays and silts and show displacements by the action of gravity. The displacement zone was delimited at the top of the slope by the formation of circular tensile fractures with stair -shaped geometries. At the base of the slope, compressive processes damaged housing, sidewalks and inclined light poles and trees. A NW-SE system of fractures was identified in which displacement velocities vary from a few millimeters to several centimeters per year. Which affects urban facilities. In this work a conceptual model of deformation is presented that integrates the geological and mechanical factors leading to landslide and land subsidence. A geophysical survey leads to evidence of how land subsidence processes increase the sliding slope.

  9. Coverage and accessibility levels of health services in the metropolitan periphery of Mexico City

    Directory of Open Access Journals (Sweden)

    Flor López

    2012-02-01

    Full Text Available The aim of this study is two fold: first, to analyze the spatial distribution of health services that different public institutions offer in the metropolitan peripheral municipalities of Mexico City; and second, give some reasons that explain that distribution. The analysis tries to demonstrate a lack of territorial approach in the construction of the social policy in the particular case of the health sector. The spatial range of health service, coverage and accessibility in the eastern part of the State of Mexico was calculate through variables much as number of doctors, nurses, beds and medical center, that the different public institution particularly IMSS, ISSSTE and ISSEMYM, offer. Results tend to show an unequal distribution of health resources either human or material, as well as a territorial disorden in their distribution with a high concentration in urban areas. Thus, analysis shows that space plays a fundamental role as a structuring factor in the application of health policies and in the planning of such services.

  10. Measurements of volatile organic compounds in Southeastern Mexico City, 1998 - 2007

    Science.gov (United States)

    Wöhrnschimmel, H.; Magaña, M.; Bueno, E.; Pérez, J. M.; González, S.; Blanco, S.; Cárdenas, B.

    2009-04-01

    Air pollution is one of the principal environmental problems in Megacities. In Mexico City, very high ozone concentrations, a result of precursors like nitrogen oxides (NOx) and volatile organic compounds (VOCs), are thought to cause severe health effects on a population of about 20 million. In addition, there are several air toxics among VOCs that threaten public health. Therefore, measuring VOCs is crucial for the definition of air quality management control strategies. In this paper we report a time series of VOC measurements, carried out in Southeastern Mexico City from 1998 to 2007. Over 26,000 grab samples were taken at different hours of the day and stations of the year, which permits a detailed analysis of changes and tendencies of VOC species, in particular the air toxics benzene, toluene and xylene (BTX). Totally, 13 species have been quantified by GC-FID. A significant decreasing tendency has been observed in VOC species, especially in BTX. The reductions were 0.1 ppbV per year for benzene and toluene. o-xylene decreased with an average rate of 0.3 ppbV per year. For the morning hours, when emissions are strongest, the reductions were even more notable (0.2, 1.3 and 0.5 ppbV per year, respectively). With this, the annual average for benzene concentrations is below the standard of 1.5 ppbV established by the European Community. The observed reductions can be attributed to an improving vehicle technology, in spite of an increasing vehicular fleet. Furthermore, in this paper we discuss total VOC data in comparison with simultaneous NOx measurements, and its implications on photochemical air pollution and validation of the emissions inventory.

  11. Comfort temperatures inside low-cost housing : case : six warm climate cities in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Azpeitia, G. [Colima Univ., Colima (Mexico). Faculty of Architecture and Design; Bojorquez, G.; Romero, R. [Autonomic Univ. of Baja California, Mexicali (Mexico). Faculty of Architecture and Design; Ruiz, P. [Autonomic Univ. of Chiapas, Tuxtla Gutierrez (Mexico). Faculty of Architecture; Ochoa, J. [Sonora Univ., Hermosillo (Mexico). School of Architecture; Perez, M. [Autonomic Univ. of Yucatan, Merida (Mexico). Faculty of Engineering; Resendiz, O. [Autonomic Univ. of Baja California Sur, La Paz (Mexico). Dept. of Fishing Engineering; Llamas, A. [Autonomic Univ. of Sinaloa, Culiacan (Mexico). Faculty of Architecture

    2009-07-01

    Mexico's National Council for Housing and National Council for Science and Technology supported a research project on the thermal comfort and energy savings in low-cost housing in Mexico. The objective was to establish thermal comfort models and provide reliable diagnostic tools for architectural designers of low-cost housing. Another objective was to promote energy savings through the adjustment of operative temperatures in air conditioning equipment. The approach of the research was an adaptive one in order to evaluate the thermal sensation of individuals in their own habitat; allow the integral study of both physiological and psychological reactions; and consider the individuals as proactive occupants, in search of their thermal comfort. The results of a field study developed according to the adaptive approach principles were presented in this paper. The survey was carried out from 2006 to 2007 in low-cost housing units in 6 Mexican cities with warm climates. In all cases, the houses were naturally ventilated. The measuring periods were determined according to the climatic characteristics of each city. The results of the field study demonstrated the importance of having standards of thermal comfort specific to each location, which must be defined through the direct response of individuals and in the environment in which they perform their daily activities. The results also showed that in hot climates, acclimated people may find comfort in temperatures around 30 degrees C during the warmest seasons. Therefore, reducing the operating temperatures of air conditioning in such conditions represents a huge opportunity for saving electricity. 16 refs., 6 tabs., 6 figs.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Female genital mutilation in Sierra Leone

    African Journals Online (AJOL)

    AJRH Managing Editor

    Health, College of Medicine and Allied Health Sciences, University of Sierra Leone; 3Plan Sierra Leone, Freetown, Sierra Leone ... Abstract. The objectives of this study were to identify decision makers for FGM and determine whether medicalization takes place in ...... cutting: research findings, gaps and directions. Culture ...

  16. Women's reports on postabortion family-planning services provided by the public-sector legal abortion program in Mexico City.

    Science.gov (United States)

    Becker, Davida; Díaz Olavarrieta, Claudia; Garcia, Sandra G; Harper, Cynthia C

    2013-05-01

    To investigate patients' views of family-planning services provided in Mexico City during abortion care at public facilities and their acceptance of postabortion contraception. In total, 402 women seeking first-trimester abortion care in Mexico City were surveyed. Logistic regression was used to test whether postabortion contraception varied according to abortion visit characteristics or patient sociodemographics. Most participants (328 [81.6%]) reported being offered contraception at their visit and 359/401 (89.5%) selected a contraceptive method for postabortion use, with 236/401 (58.9%) selecting an intrauterine device. Women who underwent surgical abortion were more likely than those who underwent medical abortion to report being offered contraception (PMexico City provide a high level of postabortion family-planning care, and uptake of postabortion contraception is high. Copyright © 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  17. Aerosol spectral absorption in the Mexico City area: results from airborne measurements during MILAGRO/INTEX B

    Directory of Open Access Journals (Sweden)

    R. W. Bergstrom

    2010-07-01

    Full Text Available This paper presents estimates of the spectral solar absorption due to atmospheric aerosols during the 2006 MILAGRO/INTEX-B (Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment field campaign. The aerosol absorption was derived from measurements of the spectral solar radiation and the spectral aerosol optical depth made on the J31 aircraft flying over the Gulf of Mexico and over Mexico City. We present the spectral single scattering albedo (SSA and aerosol absorption optical depth (AAOD for two flights over the Gulf of Mexico and three flights over Mexico City for wavelengths from 350 to approximately 1650 nm. The spectral aerosol optical properties of each case are different and illustrate the variability of the aerosol optical properties in the Mexico City area.

    The results can be described in terms of three different wavelength regions: The 350–500 nm region where the aerosol absorption often falls off sharply presumably due to organic carbonaceous particles and windblown dust; the 500–1000 nm region where the decrease with wavelength is slower presumably due to black carbon; and the near infrared spectral region (1000 nm to 1650 nm where it is difficult to obtain reliable results since the aerosol absorption is relatively small and the gas absorption dominates. However, there is an indication of a small and somewhat wavelength independent absorption in the region beyond 1000 nm.

    For one of the flights over the Gulf of Mexico near the coastline it appears that a cloud/fog formation and evaporation led to an increase of absorption possibly due to a water shell remaining on the particles after the cloud/fog had dissipated. For two of the Mexico City cases, the single scattering albedo is roughly constant between 350–500 nm consistent with other Mexico City results. In three of the cases a single absorption Angstrom exponent (AAE fits the aerosol

  18. Utilizing Tropospheric Emission Spectrometer (TES) Special Observations to Study Air Quality Over Megacities: A Case Study of Mexico City

    Science.gov (United States)

    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.

  19. Application of an extension of the MAI method to the Acapulco City, Mexico

    Science.gov (United States)

    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

  20. Fracture hydraulic conductivity in the Mexico City clayey aquitard: Field piezometer rising-head tests

    Science.gov (United States)

    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

  1. Multi-Gas analysis of ambient air using FTIR spectroscopy over Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Grutter, Michel [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D.F. (Mexico)

    2003-01-01

    A Fourier Transform Infrared (FTIR) spectrometer was used to analyze the composition of ambient air at a specific site in Mexico City metropolitan area. A continuous flow of air was passed through a multi-pass cell and the absorption spectra were collected over a period of two weeks. Quantitative analysis was performed by means of the classical-least square (CLS) method using synthetically generated spectra as references and calibration sources. Ambient levels of CO, CO{sup 2}, CH{sub 4} and N{sub 2}O are reported with a time resolution of five minutes for September 2001, showing interesting results in their diurnal patterns. Comments on the precision, detection limits and signal to noise of the instrument are included for the evaluation of this technique. Water concentrations were estimated and compared with those obtained with a relative humidity sensor. The technique of extractive FTIR for ambient trace gas monitoring was utilized in Mexico for the fist time and some potential applications are given. [Spanish] Se utilizo un espectrometro en el infrarrojo por transformadas de Fourier (FTIR) para analizar la composicion de aire ambiente en un sitio de la zona metropolitana de la Ciudad de Mexico. Para ello se introdujo un flujo constante de aire a una celda de gases de paso multiple y se colectaron los espectros durante un periodo de dos semanas. Para el analisis cuantitativo, se aplico el metodo clasico de minimos cuadrados (CLS) utilizando espectros sinteticos como referencias y fuentes de calibracion. Se observaron patrones interesantes en los niveles ambientales de CO, CO{sup 2}, CH{sub 4} y N{sub 2}O, los cuales son reportados con una resolucion temporal de cinco minutos para el mes de septiembre del 2001. En la evaluacion de esta tecnica se incluyen comentarios sobre la precision, los limites de deteccion, asi como de la relacion senal/ruido del instrumento. Se estimaron concentraciones de vapor de agua a traves de sus absorciones en el infrarrojo y se

  2. Seroepidemiology of Toxoplasma gondii in pregnant women in Aguascalientes City, Mexico: a cross-sectional study.

    Science.gov (United States)

    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; pprimary 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/

  3. On the Sound Environment of the City of Puerto Vallarta, Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    R. R. Boullosa

    2011-12-01

    Full Text Available An exploration of the sound environment in the city of Puerto Vallarta, Jalisco, Mexico, is presented. A series of interviews were held with 19 residents, of which 7 were undergraduate students, related to the perception of sound in or around places of different zones in the so-called “Viejo Vallarta” (“Old Vallarta”.The purpose was twofold, firstly, to explore the ideas people have relating to the sounds they hear in the city -and in general, the ideas they have relating to peace and tranquility and its possible relation with the sound environment-; secondly, to identify some zones or places that have a particular sound environment - positive or negative. Natural sounds emerged as an important part of the sound identity of the Vallarta region and they seem to be highlyappreciated even when the sound levels are high. Sounds related to nature emerged in all interviews: bird calls, sound of wind rustling through trees, sound of breaking sea waves, etc. The interviewees identified places or zones with a negative sonic identity due to disagreeable or high intensity sounds; traffic flow, and mostly the urban bus, is to be blamed for in the main (some mentioned radios at high volume. A series of sound levels (dBA re 20 μPa at threedifferent times of the year: February, April, and October, 2009 were measured in some locations mentioned by the interviewees. The average sound levels found on those locations considered as having a disagreeable identity were the highest.

  4. Embedding Observation into the Context of Cultural Musicology: Some Moments in Mexico City

    Directory of Open Access Journals (Sweden)

    Gisa Jähnichen

    2015-08-01

    Full Text Available Narrative analysis needs narration. In cultural musicology, a term worth being taken up in succession and contemporary modification of ethnomusicology or anthropology of music, observation is an essential skill that most elaborately reveals itself in narration. Moreover, narrations include personal features and thoughts that are often avoided in academic writings. However, they offer a wide potential for narrative analysis. This paper is to exemplarily discuss theoretical issues on cultural musicology taking a holistic approach that includes analytic description, heuristics, source interpretation by means of the so called objective hermeneutics, and phenomenology. In 2008, outlines of some small stories put exemplarily together were written down in German, and part of a story collection was published in 2009. The city being observed is Mexico City that was visited in September 2006. This paper is to review the original narrations in an extended version under the aspect of their academic effectiveness after having developed further analytical tools in the last 5 years. Besides questioning conservative academic rules of reporting outcomes, this paper also reflects on the possibilities of intense methodological developments during a relatively short time. The topics of discussion include dealing with and presenting cultural heritage (Danzas de los Voladores, history of sound preservation (Songs of the Cora Indians, music in social movements and holistic approaches to research.

  5. Seasonal and diurnal trends in black carbon properties and co-pollutants in Mexico City

    Science.gov (United States)

    Retama, A.; Baumgardner, D.; Raga, G. B.; McMeeking, G. R.; Walker, J. W.

    2015-08-01

    The Mexico City metropolitan area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short-lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e., ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown a less positive response to mitigation strategies that have been in place for almost 3 decades. For the first time, extended measurements of equivalent black carbon (eBC), derived from light absorption measurements, have been made using a Photoacoustic Extinctiometer (PAX) over a 13 month period from March 2013 through March 2014. The daily trends in workdays (Monday through Saturday) and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in the MCMA: rainy, cold and dry and warm and dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, P emissions over a 14 year period. This suggests that new methods may need to be developed that can decrease potentially toxic levels of this particulate pollutant.

  6. 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.

    Science.gov (United States)

    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.

  7. Population vulnerability due to the exposure to radon and airborne particulate matter (PM10), in Mexico City

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Ponciano-Rodriguez, G.; Gaso, M.I.; Mena, M.; Segovia, N.; Vazquez-Lopez, C.; Sajo-Bohus, L.

    2009-01-01

    Exposure to indoor radon and suspended particulate matter (SPM) is considered a high risk in lung cancer aetiology. In this paper indoor radon and SPM concentration measurements and their correlations, associated with lung cancer cases are given. Mexico City suffers high concentration of SPM as well as other photochemical pollutants such as ozone. During the last decade in Mexico City, radon and SPM have been monitored. The indoor radon measurements were done using the Nuclear Track Methodology, basically the close-end-cup device with polyallyldiglycol carbonate as detector material, followed of an established chemical etching protocol, and automatic digital image analyzer system for counting. SPM size and concentration were obtained from monitoring stations located along the city. The results show that the central-north part of Mexico City has a large concentration of SPM and the vulnerable population (older than 65 years and younger than 14 years) is located essentially in the same region. In this area, a large number of lung cancer cases were found, even if indoor radon levels were below the recommended limits.

  8. Formation of semivolatile inorganic aerosols in the Mexico City Metropolitan Area during the MILAGRO campaign

    Directory of Open Access Journals (Sweden)

    V. A. Karydis

    2011-12-01

    Full Text Available One of the most challenging tasks for chemical transport models (CTMs is the prediction of the formation and partitioning of the major semi-volatile inorganic aerosol components (nitrate, chloride, ammonium between the gas and particulate phases. In this work the PMCAMx-2008 CTM, which includes the recently developed aerosol thermodynamic model ISORROPIA-II, is applied in the Mexico City Metropolitan Area in order to simulate the formation of the major inorganic aerosol components. The main sources of SO2 (such as the Miguel Hidalgo Refinery and the Francisco Perez Rios Power Plant in the Mexico City Metropolitan Area (MCMA are located in Tula, resulting in high predicted PM1 (particulate matter with diameter less than 1 μm sulfate concentrations (over 25 μg m-3 in that area. The average predicted PM1 nitrate concentrations are up to 3 μg m−3 (with maxima up to 11 μg m−3 in and around the urban center, mostly produced from local photochemistry. The presence of calcium coming from the Tolteca area (7 μg m−3 as well as the rest of the mineral cations (1 μg m−3 potassium, 1 μg m−3 magnesium, 2 μg m−3 sodium, and 3 μg m−3 calcium from the Texcoco Lake resulted in the formation of a significant amount of aerosol nitrate in the coarse mode with concentrations up to 3 μg m−3 over these areas. PM1−10 (particulate matter with diameter between 1 and 10 μm chloride is also high and its concentration exceeds 2 μg m−3 in Texcoco Lake. PM1 ammonium concentrations peak at the center of Mexico City (2 μg m−3 and the Tula vicinity (2.5 μg m−3. The performance of the model for the major inorganic PM components (sulfate, ammonium, nitrate, chloride, sodium, calcium, and magnesium is encouraging. At the T0 measurement site, located in the

  9. African Journals Online: Sierra Leone

    African Journals Online (AJOL)

    The Sierra Leone Journal of Biomedical Research publishes papers in all fields of Medicine and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular Biology, Pharmaceutical Sciences, Biotechnology in relation to Medicine, ...

  10. IDRC in Sierra Leone

    International Development Research Centre (IDRC) Digital Library (Canada)

    team at the University College of Njala has studied urban farming. The team showed that agriculture in Freetown pro- vides a source of income for poor fami- lies, while assuring food security for the residents of the city, including thousands who fled the combat zones. Based on the results of the study, the authorities encour-.

  11. Contributors to ozone episodes in three US/Mexico border twin-cities.

    Science.gov (United States)

    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.

  12. Comparing the quality of three models of postabortion care in public hospitals in Mexico City.

    Science.gov (United States)

    Billings, Deborah L; Fuentes Velásquez, Jaime; Pérez-Cuevas, Ricardo

    2003-09-01

    Each year, an estimated 120,000 women in Mexico seek treatment in public hospitals for abortion-related complications--the country's fourth leading cause of maternal mortality. Models of postabortion care emphasizing counseling and provision of contraceptives have the potential to improve the quality of care these women receive. Between April 1997 and August 1998, women treated for abortion complications in six Mexican Institute of Social Security (IMSS) hospitals in the Mexico City metropolitan area were surveyed. Data related to patient-provider interaction, information provision and counseling were analyzed for three models of care: sharp curettage standard care, sharp curettage postabortion care and manual vacuum aspiration postabortion care. Women in the two postabortion care groups rated the quality of services they received more highly than did those receiving sharp curettage standard care. A significantly greater proportion of women treated under the postabortion care models than of those treated under the sharp curettage standard model received information about their health status before treatment, the uterine evacuation procedure, signs of postabortion complications and care at home. In addition, a greater proportion of women treated under the postabortion care models accepted a contraceptive method before leaving the facility (64-78% vs. 40%). Implementation of a postabortion care model contributes to the delivery of high-quality services to women experiencing abortion complications. The standard IMSS model of postabortion treatment should be modified to emulate those in hospitals that systematically link general counseling and family planning services to the clinical services provided to women with abortion complications.

  13. Oral health status in older adults with social security in Mexico City: Latent class analysis.

    Science.gov (United States)

    Sánchez-García, Sergio; Heredia-Ponce, Erika; Cruz-Hervert, Pablo; Juárez-Cedillo, Teresa; Cárdenas-Bahena, Angel; García-Peña, Carmen

    2014-02-01

    To explore the oral health status through a latent class analysis in elderly social security beneficiaries from Southwest Mexico City. Cross-sectional study of beneficiaries of the State Employee Social Security and Social Services Institute (ISSSTE, in Spanish) and the Mexican Institute of Social Security (IMSS, in Spanish) aged 60 years or older. Oral health conditions such as edentulism, coronal and root caries (DMFT and DFT ≥ 75 percentile), clinical attachment loss (≥ 4 mm), and healthy teeth (≤ 25 percentile) were determined. A latent class analysis (LCA) was performed to classify the oral health status of dentate patients. In total, 336 patients were included (47.9% from the ISSSTE and 52.1% from the IMSS), with an average age of 74.4 (SD = 7.1) years. The 75th percentile of the DMFT = 23 and of the DFT = 2. Of the patients, 77.9% had periodontal disease. The 25th percentile of healthy teeth = 4. A three class model is adequate, with a high classification quality (Entropy = 0.915). The patients were classified as "Edentulous" (15.2%), "Class 1 = Unfavorable" (13.7%), "Class 2 = Somewhat favorable" (10.4%), and "Class 3 = Favorable" (60.7%). Using "Class 3 = Favorable" as a reference, there was an association (OR = 3.4; 95% CI = 1.8-6.4) between being edentulous and being 75 years of age and over, compared with the 60- to 74-year age group. The oral health in elderly social security beneficiaries is not optimal. The probability of becoming edentulous increases with age. A three-class model appropriately classifies the oral health dimensions in the elderly population. Key words:Elderly, Latent class analysis (LCA), oral health, social security, Mexico.

  14. Sociodemographic differences among HIV-positive and HIV-negative recently pregnant women in Mexico City

    Science.gov (United States)

    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

  15. Oral health status in older adults with social security in Mexico City: Latent class analysis

    Science.gov (United States)

    Heredia-Ponce, Erika; Cruz-Hervert, Pablo; Juárez-Cedillo, Teresa; Cárdenas-Bahena, Ángel; García-Peña, Carmen

    2014-01-01

    Objective: To explore the oral health status through a latent class analysis in elderly social security beneficiaries from Southwest Mexico City. Material and Methods: Cross-sectional study of beneficiaries of the State Employee Social Security and Social Services Institute (ISSSTE, in Spanish) and the Mexican Institute of Social Security (IMSS, in Spanish) aged 60 years or older. Oral health conditions such as edentulism, coronal and root caries (DMFT and DFT ≥ 75 percentile), clinical attachment loss (≥ 4 mm), and healthy teeth (≤ 25 percentile) were determined. A latent class analysis (LCA) was performed to classify the oral health status of dentate patients. Results: In total, 336 patients were included (47.9% from the ISSSTE and 52.1% from the IMSS), with an average age of 74.4 (SD = 7.1) years. The 75th percentile of the DMFT = 23 and of the DFT = 2. Of the patients, 77.9% had periodontal disease. The 25th percentile of healthy teeth = 4. A three class model is adequate, with a high classification quality (Entropy = 0.915). The patients were classified as “Edentulous” (15.2%), “Class 1 = Unfavorable” (13.7%), “Class 2 = Somewhat favorable” (10.4%), and “Class 3 = Favorable” (60.7%). Using “Class 3 = Favorable” as a reference, there was an association (OR = 3.4; 95% CI = 1.8-6.4) between being edentulous and being 75 years of age and over, compared with the 60- to 74-year age group. Conclusion: The oral health in elderly social security beneficiaries is not optimal. The probability of becoming edentulous increases with age. A three-class model appropriately classifies the oral health dimensions in the elderly population. Key words:Elderly, Latent class analysis (LCA), oral health, social security, Mexico. PMID:24596632

  16. The impact of liquefied petroleum gas usage on air quality in Mexico City

    International Nuclear Information System (INIS)

    Gasca, J.; Ortiz, E.; Castillo, H.; Jaimes, J.L.; Gonzalez, U.

    2004-01-01

    Liquefied petroleum gas (LPG) is the main fuel used in the residential sector of the Metropolitan Zone in the Valley of Mexico (MZVM). LPG represents 16% of the total fuel consumption in the MZVM and its demand increased 14% from 1986 to 1999. Propane and butanes, the main compounds of LPG, constituted 29% of all non-methane hydrocarbons found in the air of Mexico City. Some researchers have reported that LPG losses are a significant cause of high ozone concentration in MZVM. Three analyses are carried out in this work to estimate LPG's share of responsibility for MZVM pollution problems. First, the correlation between LPG consumption and three ozone pollution indicators was calculated for the period of 1986-1999. The non-significant correlation of these indicators with LPG consumption on a monthly basis suggests that LPG associated emissions are not the foremost cause of ozone formation. Second, a simulation model is applied to three LPG related emission control strategies to estimate the reduction in the maximum ozone concentration. The most noticeable effect was obtained when both hydrocarbon (HC) and oxides of nitrogen (NO x ) emissions associated with LPG use were totally reduced. The other two strategies, that only reduce HC emissions, had a minimum effect on the ozone concentration. Third, organic compounds consumption in air samples captured and irradiated in outdoor smog chambers is used to determine the chemical loss rate of LPG associated species and aromatics in the MZVM. The smog chamber results showed that 70% of propane and n-butane remain at the end of a 1-day irradiation, therefore they remain in the MZVM atmosphere for several days being the reason for the high concentration of these compounds. LPG associated compounds only account for 18% of ozone formed but aromatics contribute 35% to ozone in smog chamber. (Author)

  17. The University of Guanajuato Institute of Physics (IFUG). Leon Lederman, the big boss

    Science.gov (United States)

    Félix, J.; Moreno, G.

    2000-08-01

    This paper is to honor Leon Lederman trajectory in experimental high energy physics and, in particular and most, his invaluable help to start experimental high energy physics in Mexico and in Latin America in general. That began around 1982. Now, in 1999, there are many active groups in Latin America that devote their best efforts to experimental high energy physics. In Mexico there are six groups. .

  18. Aerosol climatology over the Mexico City basin: Characterization of optical properties

    Science.gov (United States)

    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

  19. Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

    Science.gov (United States)

    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

  20. The Role of School in Educational Decisions during the Transition to High School Public Institutions in Mexico City context

    Directory of Open Access Journals (Sweden)

    Eduardo Rodríguez Rocha

    2016-09-01

    Full Text Available This article analyzes the role of schools in educational choices in the transition to public high schools in Mexico City. Secondary schools have the potential to influence educational choices, through the development of certain educational functions. This influence comes in different ways, and is relatively independent of adscriptive characteristics and previous academic performance of students.  Schools serve i as agents contributing to decision making, facilitating continuity on educational trajectories ii or as instances that do not develop explicit actions aimed to link their students to any of the options offered in the post-secondary educational system. While some schools teaching resources are destined to accompany their students during their decision process, others lack of them, abandoning them in this crucial educational event. The article is based on data provided by an ethnographic study conducted in seven high schools in southern Mexico City between January and July 2012

  1. The Biogas from bio-energy electrical power plant of Nuevo Leon; Central electrica de biogas de bioenergia de Nuevo Leon

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu F, Jose L [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Saldana M, Jaime L [Sistemas de Energia Internacional S.A. de C.V. (Mexico)

    2005-07-01

    The biogas from bio-energy electrical power plant of Nuevo Leon represents, in all the national territory, the first experience on the advantage of biogas emitted by the sanitary landfills for the generation of electrical energy. Therefore, one of the specific objectives of this paper is the one of diffusion and reproduction of the same one in other cities of Mexico and Latin America. The project is framed within the world-wide policies on the control of emissions for the reduction of the greenhouse effect gases (GEG) and its impact in the global climatic change. The gas emitted by the trash sanitary landfills, commonly known as biogas, is a gas mixture derived from the decomposition of the organic matter of the municipal trash by microorganisms in anaerobic conditions. Biogas generated in the sanitary landfills has a methane content of 55% and a 35% of carbon dioxide. The balance 10% is made up of water steam, hydrogen, nitrogen, oxygen, hydrogen sulfur and other gases in minimum amounts. [Spanish] La Central Electrica de Biogas de Bioenergia de Nuevo Leon representa, en todo el territorio nacional, la primera experiencia sobre el aprovechamiento del biogas emitido por los rellenos sanitarios para la generacion de energia electrica. Por esta razon, uno de los objetivos especificos de este trabajo es la de difusion y reproduccion del mismo en otras ciudades de Mexico y Latinoamerica. El proyecto esta enmarcado dentro de las politicas mundiales sobre el control de emisiones para la reduccion de los gases de efecto invernadero (GEI) y su impacto en el cambio climatico global. El gas emitido por la basura dispuesta en los rellenos sanitarios, comunmente conocido como biogas, es una mezcla de gases derivado de la descompensacion de la materia organica de la basura municipal por microorganismos en condiciones anaerobias. El biogas generado en los rellenos sanitarios tiene un contenido de metano del 55% y un 35% de bioxido de carbono. El 10% restante se compone de vapor

  2. Human and remote sensing data to investigate the frontiers of urbanization in the south of Mexico City.

    Science.gov (United States)

    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. Antibiotic Resistance and Biofilm Production in Staphylococcus epidermidis Strains, Isolated from a Tertiary Care Hospital in Mexico City

    OpenAIRE

    Cabrera-Contreras, Roberto; Morelos-Ramírez, Rubén; Galicia-Camacho, Ada Nelly; Meléndez-Herrada, Enrique

    2013-01-01

    Staphylococcus epidermidis strains isolated from nosocomial infections represent a serious problem worldwide. In various Mexican states several reports have shown isolates from hospitals with antibiotic resistance to methicillin. In Mexico City, there is scarce information on staphylococcal infections in hospitals. Here, our research findings are shown in a four-year period study (2006?2010) for Staphylococcus epidermidis strains. Susceptibility and/or resistance to antibiotics in SE strains ...

  4. Sources and transport of delta 14C in CO2 within the Mexico City Basin and vicinity

    OpenAIRE

    Vay, S. A; Tyler, S. C; Choi, Y.; Blake, D. R; Blake, N. J; Sachse, G. W; Diskin, G. S; Singh, H. B

    2009-01-01

    Radiocarbon samples taken over Mexico City and the surrounding region during the MILAGRO field campaign in March 2006 exhibited an unexpected distribution: (1) relatively few samples (23%) were below the North American free tropospheric background value (57 +/- 2aEuro degrees) despite the fossil fuel emissions from one of the world's most highly polluted environments; and (2) frequent enrichment well above the background value was observed. Correlate source tracer species and air transport ch...

  5. Overview of the 2006 MILAGRO Campaign in Mexico City: Transport and Transformation of Emissions from a Megacity

    Science.gov (United States)

    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

  6. Students' views of their aspirations in a flexible-rigid architecture programme in Mexico City: a case study

    OpenAIRE

    Pantoja Ayala, Hector Hugo

    2014-01-01

    This research is concerned with the aspirations -goals, hopes and desires- of architecture students. The twenty eight students investigated studied in a student-centred, problem solving programme based upon multi-disciplinary work in Mexico City. Most participant students’ mid-level education was in teacher-centred pedagogies. Despite the importance of Bourdieu’s capital volume concept –reading, museum visits, knowledge of the arts, listening to classical music, educational qualifications, pa...

  7. Prevalence of pollinosis in patients with allergic asthma, rhinitis and conjunctivitis in the South of Mexico City 2007-2013.

    Science.gov (United States)

    Gaspar-López, Arturo; López-Rocha, Eunice; Rodríguez-Mireles, Karen; Segura-Méndez, Nora; Del Rivero-Hernández, Leonel

    2014-01-01

    The prevalence of pollinosis has doubled in the past two decades. Several studies suggest that up to 50% of adult residents of Mexico City can present manifestations of respiratory allergy, and pollens from trees, grasses and weeds are a common cause. To determine the prevalence of their families and antigenic cross-reactivity allows us to offer appropriate diagnoses and treatments. To know the prevalence of sensitization of pollens to trees, grasses and weeds in adults with respiratory allergy of the South zone of Mexico City from January 2007 to December 2013. A cross-sectional, observational and prospective study was done with patients from Mexico City, referred to the National Medical Center Siglo XXI, IMSS, from 2007 to 2013 with a diagnosis of allergic rhinitis, asthma and conjunctivitis. We analyzed the results of skin prick tests to pollens from trees, grasses and weeds in selected patients. The results were analyzed using descriptive statistics. A total of 672 patients were analyzed, 70% men, the average age was 34 ± 16 years. Regarding occupation 31% were students, 48% employees and 21% housewives. Fifty-three percent had rhinitis, 47% had asthma and 40.5% had both, asthma and rhinitis. Prevalence of sensitization to weeds was 56%, 33% to trees and 11% to grasses. Sensitization to weeds is the first cause of respiratory pollinosis in the south of Mexico City, Amaranthus was the most prevalent pollen in this area. Sensitization to trees is the second cause, with a predominance of trees form Betulaceae, Fagaceae and Oleacea families. Sensitization to grass is the third cause of respiratory pollinosis. The most common are from Pooideae (Lolium perenne), Chloroideae and Cynodon/Dactylon family.

  8. Popular health education and propaganda in times of peace and war in Mexico city, 1890s-1920s.

    Science.gov (United States)

    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.

  9. Knowledge and technology transfer to improve the municipal solid waste management system of Durango City, Mexico.

    Science.gov (United States)

    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.

  10. Seasonal trends in black carbon properties and co-pollutants in Mexico City

    Science.gov (United States)

    Retama, A.; Baumgardner, D.; Raga, G. B.; McMeeking, G. R.; Walker, J. W.

    2015-04-01

    The Mexico City Metropolitan Area (MCMA) is a region that continues to grow in population and vehicular traffic as well as being the largest source of short lived climate pollutants (SLCP) in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e. ozone (O3) and carbon monoxide (CO), but particulate matter (PM2.5 and PM10) and black carbon (BC) have shown little response to mitigation strategies that have been in place for more than two decades. For the first time, extended measurements have been made of equivalent black carbon (eBC), derived from light absorption measurements made with a Photoacoustic Extinctiometer (PAX), over a 13 month period from March 2013 through March 2014. The daily trends in workday (Monday through Saturday) and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in that region: rainy, cold-dry and warm-dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, Pemissions. The other co-pollutant concentrations are also significantly less on weekends except for O3 that shows no change in maximum values from workday to Sunday. As has been noted in previous studies, this lack of change is a result of the balancing effects of lower precursor gases, i.e. VOCs, offset by lower NOx that is an O3 inhibitor. A comparison of average, maximum values of eBC measured during the one year period of the current study with maximum values measured in short field campaigns in 2000 and 2006 show that there has been no significant change in the eBC emissions over a 14 year period. This suggests that the current pollution mitigation strategy will need to be evaluated to develop new methods than can decrease potentially toxic levels of this particulate pollutant.

  11. Mexican Seismic Alert System's SAS-I algorithm review considering strong earthquakes felt in Mexico City since 1985

    Science.gov (United States)

    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

  12. [Prevalence of dyslipidemias in Mexico city and Its relation to other cardiovascular risk factors. Results from the CARMELA study].

    Science.gov (United States)

    Escobedo-de la Peña, Jorge; de Jesús-Pérez, Ramón; Schargrodsky, Herman; Champagne, Beatriz

    2014-01-01

    To estimate the prevalence of dyslipidemias in Mexico city and its relation to other cardiovascular risk factors. A cross sectional study was conducted to measure cardiovascular risk factors in Mexico City. All subjects were interviewed and anthropometric measures performed, as well as cholesterol, high-density lipoproteins (HDL-C) and triglycerides. Low-density lipoprotein (LDL-C) values were calculated. Means- as well as dyslipidemia-weighted prevalence were measured, with 95% confidence intervals. 833 males and 889 females were studied. The prevalence of cholesterol ≥ 240 mg/dl was 16.4% (95% CI: 14.2-18.7), and 34.1% (95% CI: 31.6-36.5) had values between 200 and 240 mg/dl. Very high values of triglycerides were seen in 2.6% of studied subjects and 29.9% (95% CI: 26.9-32.8) had high values. The prevalence of hypertriglyceridemia was higher in males (43.3%) than females (23%). Mean values of assessed parameters were in general higher in those with other cardiovascular risk factors. Lipid values in the population of Mexico City are high and so is the prevalence of dyslipidemias. There is an urgent need to implement health policies directed to diminish cardiovascular risk factors, mainly dyslipidemias.

  13. What does Latin Aamerican social medicine do when it governs? The case of the Mexico City government.

    Science.gov (United States)

    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.

  14. What Does Latin American Social Medicine Do When It Governs? The Case of the Mexico City Government

    Science.gov (United States)

    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

  15. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Science.gov (United States)

    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.

  16. Sweetened beverages intake, hyperuricemia and metabolic syndrome. The Mexico City Diabetes Study.

    Directory of Open Access Journals (Sweden)

    Rubén López-Molina

    2013-11-01

    Full Text Available 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 menor que 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 menor que 0.001. Conclusion. Prevalence of hyperuricemia is high. Potential association with intake of SB, resulting in metabolic alterations should be considered.

  17. GPS and GIS study of the western slope of the Chiquihuite hill in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Martínez–Yáñez

    2009-04-01

    Full Text Available The demographic explosion of the City of Mexico has forced the anarchical growth of urban development in its mountain slopes. The geologic risk conditions that prevail in such areas are rock falls and down slope creep. The topographic slope analysis shows that these some areas pose a high risk condition for the housing developments located down slope. A geodetic net work was thus developed for the establishment of a reference frame to detect medium and long term slope movement. The location of these benchmarks included rock out crops, structural containment civil structures and street sidewalks. This network was designed to be occupied using GPS fast static methods, with times of occupation no greater to 45 minutes per station. In order to keep short baselines to the reference station and its position errors within low levels we installed a reference GPS site (U CHI on the Southern part of Cerro del Chiquihuite. The Chiquihuite GPS network was monitored for 5 years. The GPS solutions were obtained by differential techniques with ambiguity solution and precise or bits, and using UCHI stations as a reference. The Chiquihuite GPS network does not show significant variations, except for the vertical component at station CH55. This site is likely to be affected by regional subsidence.

  18. Fluoride Exposure Effects and Dental Fluorosis in Children in Mexico City.

    Science.gov (United States)

    Molina-Frechero, Nelly; Gaona, Enrique; Angulo, Marina; Sánchez Pérez, Leonor; González González, Rogelio; Nevarez Rascón, Martina; Bologna-Molina, Ronell

    2015-11-26

    BACKGROUND The objective of the present study was to determine the prevalence and severity of dental fluorosis and to evaluate exposure to fluoridated products in students in the southwest part of the Federal District (Mexico City). MATERIAL AND METHODS Students between 10 and 12 years of age who were born and raised in the study zone were evaluated. The level of dental fluorosis was determined using the modified Dean index (DI) using criteria recommended by the World Health Organization (WHO). A bivariate analysis was performed with the χ2 test, and odds ratios (OR) and 95% confidence intervals (CI) are presented. Logistic regression was performed to evaluate the association between dental fluorosis and the independent variables. RESULTS A total of 239 students were evaluated. Their mean age was 11±0.82 years, and there were 122 (51%) males. Overall, dental fluorosis was found in 59% of participants; 29.3% had very mild fluorosis, 20.9% had mild fluorosis, 6.7% had moderate fluorosis, and 2.1% had severe fluorosis. The mean fluorosis score was 0.887±0.956. In the final logistic regression model, dental fluorosis was significantly associated with frequency of brushing (OR: 0.444; 95% CI: 0.297-0.666) and with the absence of parental supervision (OR: 0.636; 95% CI: 0.525-0.771). CONCLUSIONS The association found with frequency of brushing and lack of parental supervision may be contributing to the prevalence and severity of dental fluorosis.

  19. Investigation of OxProduction Rates in the Mexico City Metropolitan Area during MILAGRO

    Science.gov (United States)

    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.

  20. Characteristics of specific reading disability in children from a neuropsychological clinic in Mexico City

    Directory of Open Access Journals (Sweden)

    Poblano Adrián

    2002-01-01

    Full Text Available Objective. This report describes the main clinical features associated with specific reading disability (RD in a group of 778 school-age children studied in a Neuropsychological Clinic in Mexico City. Material and Methods. The study was performed retrospectively, using data abstracted from clinical records of subjects seen in 1995-1996. Children were mainly from low and middle economic strata and aged between 6 to 12 years. The following data were collected: age, gender, diagnosis, school grade, food intake, maternal complications during pregnancy, perinatal and postnatal neurological risk factors, and neurological signs and handedness. Results. Subjects with RD had a mean age of 102.9 months, were predominantly male (male female ratio, 2:1. Among the study group, 49.1% of the children were diagnosed with RD of a visuo-sensory-motor type, and 75.1% were from early school years (1st to 3rd grades; 27.6% showed evidence of malnutrition. A previous history of language disorders (49.2%, and a high frequency of perinatal risk factors and neurological soft signs were also found. Conclusions. This study shows that variables such as gender, food intake, and genetic and neurological risk factors, were associated with reading disabilities in school children.

  1. Application of high resolution geophysical prospecting to assess the risk related to subsurface deformationin Mexico City

    Directory of Open Access Journals (Sweden)

    F. A. Centeno-Salas

    2015-11-01

    Full Text Available In the eastern sector of Mexico City the sub soil consists of high contrasting sequences (lacustrine and volcanic inter bedded deposits that favor the development of erratic fracturing in the surface causing damage to the urban infrastructure. The high-resolution geophysical prospecting are useful tools for the assessment of ground deformation and fracturing associated with land subsidence phenomena. The GPR method allowed to evaluate the fracture propagation and deformation of vulcano-sedimentary sequences at different depths, the main electrical parameters are directly related with the gravimetric and volumetric water content and therefore with the plasticity of the near surface prospected sequences. The active seismology prospection consisted in a combination of Seismic Refraction (SR and Multichannel Analysis of Surface Waves (MASW for the estimation of the velocity of the mechanical compressive (P and the shear (S waves. The integration of both methods allowed to estimate the geomechanical parameters characterizing the studied sequence, the Poisson Ratio and the volumetric compressibility. The obtained mechanical parameters were correlated with laboratory measured parameters such as plasticity index, density, shear strength and compressibility and, GPR and seismic profiles were correlated with the mapped fracture systems in the study area. Once calibrated, the profiles allowed to identify the lithological contact between lacustrine and volcanic sequences, their variations of thicknesses in depth and to assess the deformation area in the surface. An accurate determination of the geometry of fracturing was of the most importance for the assessment of the geological risk in the study area.

  2. Assessing Pesticide Contamination to Fresh Water in Some Agricultural Sites, Close to Oaxaca City, Mexico

    Science.gov (United States)

    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),

  3. Leptin concentrations do not predict weight gain: the Mexico City Diabetes Study.

    Science.gov (United States)

    Haffner, S M; Mykkänen, L A; Gonzalez, C C; Stern, M P

    1998-07-01

    Leptin, a hormone which is produced by adipose tissue, has been shown to inhibit food intake and increase energy expenditure. In humans, leptin levels are correlated with body fat. In addition, leptin levels decline in subjects who lose weight. Yet few data exist on whether leptin levels predict weight change, except for a recent report suggesting that low leptin levels predict weight gain in very obese middle-aged Pima Indians. We have examined the association between baseline leptin levels and subsequent weight gain over 3.25 y in 180 non-diabetic participants in the Mexico City Diabetes Study. At baseline, the correlation between leptin levels and body mass index (BMI) was 0.712 in men and 0.691 in women (both P BMI (+/- 2 kg/m2) at baseline. Baseline BMI was 25.3 kg/m2 in men and 27.2 kg/m2 in women. Baseline leptin levels (ng/ml) did not predict weight gain in either men (weight gainers: 4.3; weight stable: 5.8; and weight losers: 5.2) or women (weight gainers: 17.4; weight stable: 17.7; and weight losers: 17.4). We conclude that baseline leptin levels did not predict weight change in moderately obese individuals.

  4. Connectivity, prison environment and mental health among first-time male inmates in Mexico City.

    Science.gov (United States)

    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. [Sensitization to house dust and storage mites in allergic adults from the South of Mexico city].

    Science.gov (United States)

    Ramírez-Heredia, Jennifer; Oífarrill-Romanillos, Patricia María; Guidos-Fogelbach, Guillermo; Miyagui-Nakamura, Roberto Ken; Segura-Méndez, Nora Hilda

    2013-01-01

    Mites are the most common cause of respiratory allergy. Sensitization to house dust mites is estimated at 30%. Families Euroglyphus and Dermatophagoides, are the most important. Recently, storage mites, from the families Acaridae and Glyciphagidae, have become more important as a cause of allergic respiratory diseases. The aim of this study was to identify sensitization to house dust and storage mites by skin tests in adult patients with allergic respiratory diseases. This is a descriptive study in patients with asthma and/or allergic rhinitis, with the approval of the local research committee 2009-3601-46. Patients underwent skin prick tests, with seven standardized extracts of mites (IPI ASACR). The results were analyzed with descriptive statistics. A total of 150 patients, 109 women and 41 men, with an average age 31 years (±11) were studied. The more common allergic diseases in this group of patients were: asthma and rhinitis 72 and 26%, respectively, and asthma plus rhinitis 3.2%. Positive skin tests for Dermatophagoides pteronyssinus and Dermatophagoides farinae were 82.1% 71.5%, respectively, and for storage mites: A. siro 51.7%, Tyrophagus 47.4%, Glycyphagus 47.7%, B. tropicalis 39.7% and Lepidoglyphus 39.1%. Storage mites produced greater sensitization than house dust mites, 32% vs 10%. The results show that adult patients with respiratory allergy, in southern Mexico City, have a higher rate of sensitization to storage mites than the one reported in the literature.

  6. Irrigation water quality in southern Mexico City based on bacterial and heavy metal analyses

    International Nuclear Information System (INIS)

    Solis, C.; Sandoval, J.; Perez-Vega, H.; Mazari-Hiriart, M.

    2006-01-01

    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

  7. Irrigation water quality in southern Mexico City based on bacterial and heavy metal analyses

    Energy Technology Data Exchange (ETDEWEB)

    Solis, C. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo Postal 20-364, 01000 Mexico, DF (Mexico)]. E-mail: corina@fisica.unam.mx; Sandoval, J. [Instituto de Ecologia, Universidad Nacional Autonoma de Mexico, Apdo Postal 70-275, 04510 Mexico, DF (Mexico); Perez-Vega, H. [Ciencias Agropecuarias, Universidad Juarez Autonoma de Tabasco, Ave. Universidad S/N. Zona de la Cultura, 86040 Villa Hermosa, Tabasco (Mexico); Mazari-Hiriart, M. [Instituto de Ecologia, Universidad Nacional Autonoma de Mexico, Apdo Postal 70-275, 04510 Mexico, DF (Mexico)

    2006-08-15

    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.

  8. Atmospheric PM2.5 Mercury in the Metropolitan Area of Mexico City.

    Science.gov (United States)

    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.

  9. Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City.

    Science.gov (United States)

    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.

  10. Predicting Women's Utilization of Primary Care Mental Health Services in Mexico City.

    Science.gov (United States)

    Mendoza, Karla; Ulloa, Arianna; Saavedra, Nayelhi; Galván, Jorge; Berenzon, Shoshana

    2017-04-01

    To analyze factors associated with and predicting Mexican women seeking primary care mental health services (PCMHS) and provide suggestions to increase PCMHS utilization. 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. 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). Primary care providers play a fundamental role in women's decisions to seek PCMHS. Proper referrals to PCMHS should be encouraged.

  11. Self-perception of oral health in older adults from Mexico City

    Science.gov (United States)

    Cárdenas-Bahena, Ángel; Velázquez-Olmedo, Laura Bárbara; Falcón-Flores, José Armando; García-Zámano, Itzel Estela; Montes-Salmerón, Rosa Elena; Reza-Bravo, Gustavo Gil; Sánchez-García, Sergio

    2018-01-01

    Quality of life related to oral health is assessed through the individual’s self-perceived oral health (SPOH). The objective is to determine SPOH in relation to socio-demographic and health characteristics in older adults beneficiaries from the Instituto Mexicano del Seguro Social (IMSS) in Mexico City. Cross-sectional study. We used data collection with questionnaire and assessment scales related to socio-demographic, health and dependency variables, as well as the visit to the dentist, the use of removable dental prostheses and SPOH. The self-perception means (Geriatric/General Oral Health Assessment Index-GOHAI) were calculated, and we used Student’s t, ANOVA and Bonferroni post hoc tests. 60.5% were women; the average age of population was 68.23 ± 7.0. GOHAI total mean was 48.07 (48.05-48.08). Compared to their counterparts, people with the next features showed marked improvement in SPOH: of 60-69 years of age, separated or divorced, ≥ 7 years of study, paid work, living alone, no smoking, drinking alcohol, with a good health perception, low weight, no cognitive impairment, no depression, no anxiety, no comorbidity, consumption < 5 drugs, with limitations in basic activities, without limitations in instrumental activities, who did not visit the dentist and who did not use removable prosthesis. The concept of quality of life essentially incorporates the SPOH as a need in the evaluation of health outcomes.

  12. Air pollution, inflammation and preterm birth in Mexico City: Study design and methods

    Science.gov (United States)

    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

  13. Addiction-Related Stigma and Discrimination: A Qualitative Study in Treatment Centers in Mexico City.

    Science.gov (United States)

    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.

  14. Back to school: drop-out and return to school among youth in Mexico City

    Directory of Open Access Journals (Sweden)

    Emilio Blanco Bosco

    2014-09-01

    Full Text Available This paper addresses the return to school among youngsters in Mexico City that had dropped out of school at some point between the beginning of elementary school and the end of upper secondary level. More than a quarter of these youngsters returned to school, which supports the idea that quitting school does not equal to the end of the educational career. There is a significant association between the socioeconomic origin and the probability of an individual returning to school, although weaker (and in the opposite direction than correlation with the probability of dropping out. Complex, non-linear patterns were found between the return and the moment when the drop out occurred, which questions mainstream theories about educational decisions. It was also found that an important proportion of those who returned to school completed upper secondary education, particularly remarkable among youngsters of lower social origins. The evidence supports the idea of considering both the effects of the social structure and the individual agency, and particularly to take into account the actors’ rationality.

  15. Heavy metals in urban road sediments of the city of Mexicali, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Meza T, L. M.; Quintero N, M.; Valdez S, B., E-mail: montserrat.meza@uabc.edu.mx [Universidad Autonoma de Baja California, Facultad de Ingenieria, Unidad Mexicali, 21280 Mexicali, Baja California (Mexico)

    2014-07-01

    A chemical sediment characterization of urban streets in the city of Mexicali at Baja California, Mexico, was conducted to estimate the most important heavy metals along with PM{sub 10} and PM{sub 2.5} emission factors to evaluate the amount of particulate matter. Sampling was conducted from february to may 2008, following a random statistical design, in 60 sampling sites on a geo referenced map at UTM 11 North. Samples were identified and treated in the laboratory, after undergoing cracking, drying, sieving, and weighing to get less than 75 microns of sediment by using a dry method. Twelve representative samples were selected for chemical characterization using energy dispersive X-rays (EDX) and inductively coupled plasma (Icp). The most significant elements found were zinc (Zn) and lead (Pb) with concentrations ranging from 1 to 15 mg/kg and 11 to 25 mg/kg, respectively, corresponding to the third classification from a reference set of a study by US EPA in 1981-1997. The clay type known as illite was identified in four specific samples. (author)

  16. Tuberculosis and systemic lupus erythematosus: a case-control study in Mexico City.

    Science.gov (United States)

    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. Impact air quality by wildfire and agricultural fire in Mexico city 2015

    Science.gov (United States)

    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

  18. Barriers to Integrating Mental Health Services in Community-Based Primary Care Settings in Mexico City: A Qualitative Analysis.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  20. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, Eric; Emmons, L.; Karl, Thomas G.; Flocke, Frank M.; Hills, A. J.; Madronich, Sasha; Lee-Taylor, J.; Fried, Alan; Weibring, P.; Walega, J.; Richter, Dirk; Tie, X.; Mauldin, L.; Campos, Teresa; Weinheimer, Andrew J.; Knapp, David; Sive, B.; Kleinman, Lawrence I.; Springston, S.; Zaveri, Rahul A.; Ortega, John V.; Voss, Paul B.; Blake, D. R.; Baker, Angela K.; Warneke, Carsten; Welsh-Bon, Daniel; de Gouw, Joost A.; Zheng, J.; Zhang, Renyi; Rudolph, Jochen; Junkermann, W.; Riemer, D.

    2010-01-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on March 18 and the NCAR C130 one day later on March 19. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the March 19 plume and to help interpret the OH

  1. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, E.; Springston, S.; Karl, T.; Emmons, L.; Flocke, F.; Hills, A. J.; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D., Tie, X.; Mauldin, L.; Campos, T.; Sive, B.; Kleinman, L.; Springston, S., Zaveri, R.; deGouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

    2009-11-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on 18 March and the NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the 19 March plume and to help interpret the OH

  2. A Tale of Two Cities: San Diego (USA) and Tijuana (Mexico) El Niño Readiness

    Science.gov (United States)

    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.

  3. Evaluation of New Secondary Organic Aerosol Models for a Case Study in Mexico City

    Science.gov (United States)

    Dzepina, K.; Volkamer, R.; Madronich, S.; Tulet, P.; Ulbrich, I.; Zhang, Q.; Cappa, C. D.; Ziemann, P. J.; Jimenez, J. L.

    2008-12-01

    Recent field studies have found large discrepancies in the measured vs. modeled SOA mass loadings in both urban and regional polluted atmospheres. The reasons for these large differences are unclear. Here we revisit a case study of SOA formation in Mexico City described by Volkamer et al. (2006) and show that the increase in OA/CO during photochemistry is consistent with results from several groups during MILAGRO, during a period when the impact of regional biomass burning is minor or negligible. Then we use the case study to evaluate three new SOA models: 1) the update of aromatic SOA yields from recent chamber experiments (Ng et al., 2007); 2) the formation of SOA from glyoxal (Volkamer et al., 2007); 3) and the formation of SOA from primary semivolatile and intermediate volatility species (P-S/IVOC) (Robinson et al., 2007). We also evaluate the effect of reduced partitioning of SOA into POA (Song et al., 2007). Traditional SOA precursors (mainly aromatics) by themselves still fail to produce enough SOA to match the observations by a factor of ~7. The new low-NOx aromatic pathways with very high SOA yields make a negligible contribution in this urban environment as the RO2 + NO reaction dominates the fate of the RO2 radicals. Glyoxal contributes several μg m-3 to SOA formation, with similar timing as the measurements. P-S/IVOC concentrations are estimated as in equilibrium with measured POA, and these species introduce a large amount of carbon that was not in models before. With the formulation in Robinson et al. (2007) these species have a high SOA yield, and this mechanism can close the gap in SOA mass between measurements and models in our case study. However, this model has many parameters that are not well constrained and much experimental work is needed for its realistic assessment. The volatility of model SOA is too high when compared to the measurements, while the O/C of all model SOA is somewhat lower than the observations. The effects of dilution and

  4. Ozone concentrations at a selected high-elevation forest site downwind Mexico City

    Science.gov (United States)

    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

  5. BORDER EFFECTS ON DSM-5 ALCOHOL USE DISORDERS ON BOTH SIDES OF THE U.S.-MEXICO BORDER

    Science.gov (United States)

    Cherpitel, Cheryl J.; Ye, Yu; Bond, Jason; Zemore, Sarah E.; Borges, Guilherme; Greenfield, Thomas K.

    2015-01-01

    Background Little epidemiological evidence exists on alcohol use and related problems along the U.S.-Mexico border, although the borderlands have been the focus of recent media attention related to the escalating drug/violence “epidemic”. In the present study the relationship of proximity of living at the border and alcohol use disorders (AUDs) is analyzed from the U.S.-Mexico Study on Alcohol and Related Conditions (UMSARC). Methods Household surveys were conducted on 2,336 Mexican Americans in Texas (771 in a non-border city and 1,565 from three border cities located in the three poorest counties in the U.S.) and 2,460 Mexicans from the states of Nuevo Leon and Tamaulipas in Mexico (811 in a non-border city and 1,649 from three cities which are sister cities to the Texas border sites). Results Among current drinkers, prevalence of AUD was marginally greater (pMexico (pMexico. Conclusion The data suggest that border proximity may affect AUD in both the U.S. and Mexico, but in the opposite direction, and may be related to the relative perceived or actual stress of living in the respective communities. PMID:25649987

  6. Barriers and missed opportunities to HIV testing among injection drug users in two Mexico--US border cities.

    Science.gov (United States)

    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.

  7. Bio-climatic strategy for energy saving in corporative buildings. City Juarez, Chihuahua, Mexico; Estrategia bioclimatica para ahorro energetico en edificios corporativos. Ciudad Juarez, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Staines Orozco, E. R.

    2008-07-01

    Ciudad Juarez Chihuahua in Mexico is located in of de biggest Desert of Arid America called Chihuahuan Desert, and is there in where this border city with United State of North America and one of the border cities of greater commercial importance (a million six hundred thousands pop. approx.) has been develop to great influence of wasteful constructive systems of nonrenewable resources as they are the gas and electricity. These building take back surpassed models. In this article presents a design of a model of corporative building of five floors that counts including all a strategy from the process of architectonic design to the applications of echo passive and active Technologies (hybrid) like one of a ventilation tower, strategy that applied guarantees the significant saving to use energy. (Author)

  8. View From a Megacity: Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City.

    Science.gov (United States)

    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.

  9. Volatile aromatic compounds in Mexico City atmosphere: levels and source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Mugica, V. [Universidad Autonoma Metropolitana - Unidad Azcapotzalco, Mexico, D.F. (Mexico); Ruiz, M.E. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Watson, J.; Chow, J. [Desert Research Institute, Reno, Nevada (United States)

    2003-01-01

    Samples of ambient air were simultaneously collected at three different sites of Mexico City in March of 1997 in order to quantify the most abundant volatile aromatic compounds and estimate the source contributions by application of the chemical mass balance model (CMB). Volatile aromatic compounds were around 20% of the total of non-methane hydrocarbons present in morning air samples. The most abundant volatile aromatic species in urban air were toluene and xylenes followed by 1, 2, 4 trimethylbenzene, benzene, ethylbenzene, metaethyltoluene, 1, 3, 5 trimethylbenzene, styrene, n propylbenzene, and isopropylbenzene. Sampling campaigns were carried out at crossroads, a bus station, a parking place, and areas where solvents and petroleum distillates are used, with the objective of determining people's exposure to volatile aromatic compounds. The CMB was applied for estimating the contribution of different sources to the presence of each one of the most abundant aromatic compounds. Motor vehicle exhaust was the main source of all aromatic compounds, especially gasoline exhaust, although diesel exhausts and asphalt operations also accounted for toluene, xylenes, ethylbenzene, propylbenzenes, and styrene. Graphic arts and paint applications had an important impact on the presence of toluene. [Spanish] Se colectaron simultaneamente muestras de aire ambiente en tres sitios de la Ciudad de Mexico durante el mes de marzo de 1997 con el fin de conocer las concentraciones y el origen de compuestos aromaticos utilizando el modelo de balance de masa de especies quimicas (CMB). Los compuestos aromaticos volatiles representaron alrededor del 20% del total de hidrocarburos no metalicos presentes en las muestras matutinas colectadas. Las especies aromaticas volatiles mas abundantes en el ambiente fueron el tolueno y los xilenos, seguidos por 1, 2, 4 trimetilbenceno, benceno, etilbenceno, metaetiltolueno, nporpilbenceno, isopropilbenceno, 1, 3, 5 trimetilbenceno y estireno. Se

  10. Trinational Library Forum Proceedings = Memorias [del] Foro Trinacional de Bibliotecas (5th, Mexico City, Mexico, February 23-25, 1995).

    Science.gov (United States)

    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)…

  11. Ambient Particulate Matter during MILAGRO in Mexico City: Main Findings, Impacts (on AQ and Climate), and Future Research Needs

    Science.gov (United States)

    Jimenez, Jose-Luis; Schauer, James J.; Molina, Luisa T.; MILAGRO Pm Team

    2010-05-01

    The MILAGRO campaign was a large international field experiments conduced in Mexico City and Central Mexico during March 2006. We present an overview of the main findings related to particulate matter and aerosol radiative properties. PM levels inside Mexico City were similar or higher than those in the most polluted North American cities, but ~5 times lower than levels in the most polluted Asian megacities During the study, PM10 and PM2.5 concentrations in the urban area of were about double the concentrations in the rural areas surrounding Mexico City. PM2.5 made up about half of the PM10 concentrations, with small amounts of mass in the PM2.5-PM1.0 range. Mineral matter made up approximately 25% of the PM10 and on average 15% and 28% of the PM2.5 in the urban and rural areas, respectively. Approximately 25% of the PM2.5 was secondary inorganic ions with the remaining PM2.5 mass being comprised of largely carbonaceous aerosol. Except for surface measurements at the central sampling sites in Mexico city, the elemental carbon mass absorption efficiency was relatively constant for aircraft and surface measurements throughout the study, contrary to expectations. Although different organic aerosol (OA) source apportionment methods had some differences, there was agreement that the dominant sources of carbonaceous aerosol were secondary OA (SOA), biomass burning, and mobile sources. The impact of biomass burning to the aerosol outflow from the region was much larger than to the surface concentrations inside the city. SOA formation from primary semivolatile and intermediate volatility precursors has the potential to close the gap in predicted vs. measured SOA, while formation from glyoxal also makes an important contribution, especially to organic oxygen. Biogenic SOA advected from the coastal mountain ranges contributes about 1 μg m-3 to concentrations in the MCMA. Primary OA from anthropogenic and biomass burning sources was found to be semivolatile, while secondary

  12. The Urban Tree as a Tool to Mitigate the Urban Heat Island in Mexico City: A Simple Phenomenological Model.

    Science.gov (United States)

    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.

  13. The growth of suicide ideation, plan and attempt among young adults in the Mexico City metropolitan area.

    Science.gov (United States)

    Borges, G; Benjet, C; Orozco, R; Medina-Mora, M-E

    2017-12-01

    Low and middle income countries share a heavy burden of suicide with about three in every four suicides occurring in these countries. Mexico has witnessed a growing trend in suicide deaths; if this trend is not simply a reflection of better reporting of suicide on death certificates, then this increase should logically be accompanied by an increasing trend in suicide ideation, plan and attempts, but we lack information on the trends for suicide ideation, plan and attempt for this period. We therefore aim to report changes for suicidal behaviour for the period 2001-2013 in the Mexico City Metropolitan Area. Using two cross-sectional surveys conducted in Mexico in 2001 and 2013, we report the lifetime and 12-month prevalence of suicide ideation, plan and attempt and changes in treatment for these problems among respondents aged 19-26 living in the Mexico City Metropolitan Area 12 years apart. To estimate the changes in prevalence for each outcome, we used generalised linear models to calculate prevalence ratios (PR; the prevalence rate in the exposed (year 2013) divided by the prevalence rate in the unexposed (year 2001-2002), adjusting for sociodemographic variables. While increases in the prevalence are noted everywhere, statistical comparisons only found differences for lifetime ideation (PR = 3.1; 95% CI = 1.7-5.8) and a borderline difference for suicide attempt (PR = 2.2; 95% CI = 1.0-4.9). No attempt within the last 12-months was reported in 2001, but the prevalence in 2013 reached 1.5% (18 cases). While PRs for 12-month prevalence were all above the null, none reached statistically significant differences. During this 12-year period, the distribution of mental disorders and the use of services for mental disorders among suicide ideators, planners and attempters did not change in any noticeable way. The limitations of our data are the small number of participants in the 2001 survey, the low follow-up rate for the survey in 2013 and that while representative

  14. Prevalent HLA Class II Alleles in Mexico City Appear to Confer Resistance to the Development of Amebic Liver Abscess.

    Science.gov (United States)

    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.

  15. Neumonitis por hipersensibilidad en la ciudad de México Hypersensitivity pneumonitis in Mexico City

    Directory of Open Access Journals (Sweden)

    José G. Carrillo-Rodríguez

    2000-06-01

    Full Text Available OBJETIVO: Determinar la asociación entre la zona urbana de origen del paciente en la ciudad de México y la prevalencia de neumonitis por hipersensibilidad inducida por antígeno aviario. MATERIAL Y MÉTODOS: Se trata de un estudio de casos y controles realizado en el Instituto Nacional de Enfermedades Respiratorias, en la ciudad de México, en el año de 1999. Se estudiaron 109 casos con neumonitis por hipersensibilidad y 184 controles: de éstos, 39, con fibrosis pulmonar idiopática; 63, con tuberculosis pulmonar, y 82, con asma. La ciudad de México y las zonas conurbadas se dividieron en cinco zonas geográficas: centro, noreste, sureste, noroeste y el suroeste. Se calcularon las prevalencias de las diferentes enfermedades por zona urbana de los pacientes que participaron en el estudio; como medida de asociación, se estimó la razón de momios, con un intervalo de confianza al 95%. Asimismo, se realizó regresión logística múltiple ajustando por edad, sexo y estrato socioeconómico. RESULTADOS: Ochenta casos de neumonitis por hipersensibilidad se concentraron en el sur del noreste de las zonas conurbadas y la parte norte del sureste de la ciudad de México, 48 y 32, respectivamente (RM= 3.86, IC 95% 2.17-6.96. Treinta y seis controles de asma se localizaron en el suroeste de la ciudad de México, zona donde se ubica el Intituto Nacional de Enfermedades Respiratorias (pOBJECTIVE: To investigate the association between the urban area of origin of patients and the prevalence of hypersensitivity pneumonitis (HP, induced by avian antigens. MATERIAL AND METHODS: A case-control study was conducted in 1999 at the National Institute of Respiratory Diseases (NIRD. Cases were 109 consecutive HP patients and controls were 184 patients: 39 with idiopathic pulmonary fibrosis (IPF, 63 with pulmonary tuberculosis (PTB, and 82 with asthma. Mexico City and surrounding counties (SC were divided into 5 geographical areas: 1 Downtown; 2 North-East (NE; 3

  16. Ground-based and aircraft measurements of volatile organic compounds in United States and Mexico City urban atmospheres

    Science.gov (United States)

    Baker, Angela K.

    This study presents measurements made from ground-based samples collected in 28 cities in the United States and in Mexico City, as well as data from aircraft measurements made of outflow from these urban areas. Urban samples are used to identify and quantify the major volatile organic compounds (VOCs) present in the cities studied, while aircraft samples are used for comparison and to examine both local and transported pollutants. Between 1999 and 2005 whole air canister samples were collected in 28 United States cities during the summertime (August/September) and in 8 cities during November, February and May. Samples were analyzed for methane, carbon monoxide (CO), NMHCs and halocarbons. Mixing ratios of NMHCs exhibited high inter- and intra-city variability, so ratios of individual NMHCs to CO, a combustion tracer, were examined to facilitate comparison between cities. Most NMHCs were found to have correlation coefficients (r2 ) greater than 0.6, highlighting the influence of vehicular emissions on NMHC mixing ratios. Notable exceptions were the C2-C 4 alkanes, which generally had poor correlations with CO. Mixing ratios of halocarbons regulated by the Montreal Protocol highlighted the success of regulatory efforts in the United States, while measurements of unregulated species identified strong urban sources. In Mexico City samples were collected at two fixed sites (T0 and T1) and throughout the central urban area. The T0 site was at an urban/industrial location while T1 was a suburban location. All samples were analyzed for methane, CO, NMHCs, halocarbons and alkyl nitrates. The most abundant NMHC at all sites was propane, the major component of liquefied petroleum gas (LPG). For nearly all species, mixing ratios were the greatest at the T0 site, where mean values of many NMHCs were in excess of 10 ppbv and where halocarbons were up to an order of magnitude greater than background values. Simple calculations of OH loss frequencies at each site show ethene and

  17. Basic statistics of PM2.5 and PM10 in the atmosphere of Mexico City.

    Science.gov (United States)

    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

  18. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Directory of Open Access Journals (Sweden)

    E. C. Apel

    2010-03-01

    Full Text Available The volatile organic compound (VOC distribution in the Mexico City Metropolitan Area (MCMA and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs but with a substantial contribution from oxygenated volatile organic compounds (OVOCs, predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry model and MOZART (Model for Ozone and Related chemical Tracers were able to approximate the observed MCMA daytime patterns and absolute values of the VOC OH reactivity. The MOZART model is also in agreement with observations showing that NMHCs dominate the reactivity distribution except in the afternoon hours. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height.

    A northeast transport event was studied in which air originating in the MCMA was intercepted aloft with the Department of Energy (DOE G1 on 18 March and downwind with the National Center for Atmospheric Research (NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind; ozone was shown to be photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial extent and temporal evolution of the plume

  19. Preventing HIV Transmission Among Partners of HIV-Positive Male Sex Workers in Mexico City: A Modeling Study.

    Science.gov (United States)

    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.

  20. Analysis of Wedge-like Response in Mexico City during the September 19th, 2017 Puebla-Morelos Earthquake

    Science.gov (United States)

    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.

  1. Escherichia coli clonal group A among uropathogenic infections in Mexico City.

    Science.gov (United States)

    Manjarrez-Hernandez, Angel; Molina-López, José; Gavilanes-Parra, Sandra; Hernandez-Castro, Rigoberto

    2016-12-01

    Escherichia coli clonal group A (CGA) causes urinary tract and other extra-intestinal infections in humans. CGA is an important cause of trimethoprim/sulfamethoxazole (SXT) resistance in extra-intestinal pathogens. We examined the extent to which resistance in this area is related to CGA dissemination of E. coli from urinary tract infections (UTIs) in Mexico City. The virulence backgrounds of the isolates were also characterized. In this study, the frequency of resistance to SXT used for UTI treatment was high (56-65 %), and CGA isolates accounted for 9 of the 78 SXT-resistant isolates (11.5 %). Although all CGA isolates were found to be multidrug resistant (MDR), none of them were extended-spectrum β-lactamase-producing organisms. The prevalence of CGA among the 45 MDR isolates that we identified was 20 %, indicating that this clonal group moderately contributes to the antibiotic resistance of uropathogenic E. coli isolates in this region. Most of the nine CGA isolates carried transferable, large-size plasmids of approximately 80 to 100 kb, which were able to transfer antimicrobial resistance to E. coli J53 in mating assays. CGA isolates mainly belonged to phylogenetic groups F and D. We found no association between antimicrobial resistance and virulence-associated genes: the median virulence scores of CGA isolates were slightly higher (4.6) than those of non-CGA isolates, whether they were susceptible (3.7) or resistant (3.5) to SXT. Our results indicate that CGA is not a major contributor to the high level of resistance to SXT in this region but, instead, seems to be an important constituent of MDR isolates from UTIs.

  2. Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

    Directory of Open Access Journals (Sweden)

    E. Velasco

    2008-06-01

    Full Text Available The evolution of ozone (O3 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 O3 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 the formation of an upper residual layer during nighttime carrying over a fraction of the O3 from the previous day that contributes to the background concentration in surrounding regions. At the same time the release of heat stored in the urban surface forms a shallow unstable layer close to the ground, where the nocturnal emissions are trapped. After sunrise an O3 balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with nitric oxide, delaying the ground-level O3 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.

  3. Impacts of HONO sources on the photochemistry in Mexico City during the MCMA-2006/MILAGO Campaign

    Directory of Open Access Journals (Sweden)

    G. Li

    2010-07-01

    Full Text Available The contribution of HONO sources to the photochemistry in Mexico City is investigated during the MCMA-2006/MILAGO Campaign using the WRF-CHEM model. Besides the homogeneous reaction of NO with OH, four additional HONO sources are considered in the WRF-CHEM model: secondary HONO formation from NO2 heterogeneous reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 heterogeneous reaction on aerosol and ground surfaces. The WRF-CHEM model with the five HONO sources performs reasonably well in tracking the observed diurnal variation of HONO concentrations. The HONO sources included are found to significantly improve the HOx (OH+HO2 simulations during daytime and the partition of NO/NO2 in the morning. The HONO sources also accelerate the accumulation of O3 concentrations in the morning by about 2 h and subsequently result in a noticeable enhancement of O3 concentrations over the course of the day with a midday average of about 6 ppb. Furthermore, these HONO sources play a very important role in the formation of secondary aerosols in the morning. They substantially enhance the secondary organic aerosol concentrations by a factor of 2 on average in the morning, although they contribute less during the rest of the day. The simulated particle-phase nitrate and ammonium are also substantially enhanced in the morning when the four HONO sources are included, in good agreement with the measurements. The impact of the HONO sources on the sulfate aerosols is negligible because of the inefficient conversion of H2SO4 from SO2 reacting with OH.

  4. Obesity, eating behaviour and mental health among university students in Mexico City.

    Science.gov (United States)

    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.

  5. Microbiological implications of periurban agriculture and water reuse in Mexico City.

    Directory of Open Access Journals (Sweden)

    Marisa Mazari-Hiriart

    Full Text Available 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

  6. Mobile mini-DOAS measurement of the outflow of NO2 and HCHO from Mexico City

    Directory of Open Access Journals (Sweden)

    L. Molina

    2009-08-01

    Full Text Available We here present the results from mobile measurements using two ground-based zenith viewing Differential Optical Absorption Spectroscopy (DOAS instruments. The measurement was performed in a cross-section of the plume from the Mexico City Metropolitan Area (MCMA on 10 March 2006 as part of the MILAGRO field campaign. The two instruments operated in the UV and the visible wavelength region respectively and have been used to derive the differential vertical columns of HCHO and NO2 above the measurement route. This is the first time the mobile mini-DOAS instrument has been able to measure HCHO, one of the chemically most important and interesting gases in the polluted urban atmosphere. Using a mass-averaged wind speed and wind direction from the WRF model the instantaneous flux of HCHO and NO2 has been calculated from the measurements and the results are compared to the CAMx chemical model. The calculated flux through the measured cross-section was 1.9 (1.5–2.2 kg/s of HCHO and 4.4 (4.0–5.0 kg/s of NO2 using the UV instrument and 3.66 (3.63–3.73 kg/s of NO2 using the visible light instrument. The modeled values from CAMx for the outflow of both NO2 and HCHO, 1.1 and 3.6 kg/s, respectively, show a reasonable agreement with the measurement derived fluxes.

  7. Study of the regional air quality south of Mexico City (Morelos state).

    Science.gov (United States)

    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.

  8. Warm autoimmune hemolytic anemia: experience from a single referral center in Mexico City.

    Science.gov (United States)

    Alonso, Hernandez-Company; Manuel, Anguiano-Alvarez Victor; Amir, Carmona Gonzalez Carlos; Sergio, Rodriguez-Rodriguez; Allan, Pomerantz; Xavier, Lopez-Karpovitch; Juventina, Tuna-Aguilar Elena

    2017-03-01

    Autoimmune hemolytic anemia (AIHA) is characterized by an autoimmune-mediated destruction of red blood cells. Warm AIHA (wAIHA) represents 60% of AIHA cases and is associated with the positive detection of IgG and C3d in the direct antiglobulin test (DAT). This study aimed to assess the clinical and laboratorial differences between primary and secondary wAIHA patients from a referral center in Mexico City. All patients diagnosed with wAIHA in our institution from January 1992 to December 2015 were included and received corticosteroids as the first-line treatment. We analyzed the response to the first-line treatment, relapse-free survival, and time to splenectomy. Eighty-nine patients were included. Secondary wAIHA represented 55.1% of the cases. At diagnosis, secondary wAIHA patients showed a DAT mixed pattern more frequently than primary wAIHA patients (36.7 vs. 17.5%, P <0.001). In the survival analysis, patients with secondary wAIHA had a lower time to response (18 vs. 37 days, P =0.05), median disease-free survival (28.51 vs. 50.95 weeks, P =0.018), and time to splenectomy (43.5 vs. 61 wks, P =0.029) than those with primary wAIHA. Due to economic constraints, rituximab was considered as the third-line treatment in only two patients. Secondary wAIHA may benefit from a longer low-dose steroid maintenance period mainly due to its shorter time to relapse and time to splenectomy than primary wAIHA.

  9. Characterization of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

    International Nuclear Information System (INIS)

    Moffet, Ryan C.; Desyaterik, Yury; Hopkins, Rebecca J.; Tivanski, Alexei V.; Gilles, Marry K.; Wang, Yan A.; Shutthanandan, V.; Molina, Luisa T.; Abraham, Rodrigo G.; Johnson, Kirsten S.; Mugica, Violeta; Molina, Mario J.; Laskin, Alexander; Prather, Kimberly A.

    2008-01-01

    During the March, 2006 MILAGRO campaign, measurements in the Northern Mexico City Metropolitan Area revealed the frequent appearance of particles with a characteristically high content of internally mixed Zn, Pb, Cl, and P. A comprehensive study of the chemical and physical properties of these particles was performed using a complementary combination of aerosol measurement techniques. Individual particles were analyzed using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) and Computer Controlled Scanning Electron Microscopy/Energy Dispersive X-Ray spectroscopy (CCSEM/EDX). Proton Induced X-Ray Emission (PIXE) analysis of bulk aerosol samples provided time-resolved mass concentrations of individual elements. The PIXE measurements indicated that Zn is more strongly correlated with Cl than with any other element and that Zn concentrations are higher than other non-ferrous transition metals. The Zn- and Pb-containing particles have both spherical and non-spherical morphologies. Many metal rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2 6H2O as indicated by scanning transmission x-ray microscopy/near edge X-ray absorption spectroscopy (STXM/NEXAFS). The Zn and Pb rich particles were primarily in the submicron size range and internally mixed with elemental carbon. The unique chemical associations most closely match signatures acquired for garbage incineration. This unique combination of complementary analytical techniques has allowed for a comprehensive evaluation of Zn- and Pb- containing particles in a complex urban environment, highlighting unique characteristics that give powerful insight into their origin

  10. Frequency and risk factors associated with dry eye in patients attending a tertiary care ophthalmology center in Mexico City

    Directory of Open Access Journals (Sweden)

    Martinez JD

    2016-07-01

    Full Text Available Jaime D Martinez,1 Anat Galor,2,3 Nallely Ramos-Betancourt,1 Andrés Lisker-Cervantes,1 Francisco Beltrán,1 Jorge Ozorno-Zárate,1 Valeria Sánchez-Huerta,1 Marco-Antonio Torres-Vera,1 Everardo Hernández-Quintela1 1Cornea and External Diseases Service, Asociación Para Evitar la Ceguera en Mexico (Association to prevent blindness in Mexico, Universidad Nacional Autónoma de México, Mexico City, Mexico; 2Department of Ophthalmology, Miami Veterans Affairs Medical Center, 3Cornea and External Diseases Division, Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA Purpose: The purpose of this study was to ascertain the frequency and risk factors of dry eye (DE among patients attending a tertiary care ophthalmology center in Mexico.Methods: Approximately 338 consecutive new patients attending a tertiary care ophthalmology center in Mexico City underwent an ocular surface examination, which included tear film break-up time, fluorescein corneal staining, Schirmer’s test, and evaluation of meibum quality. Symptoms of DE were evaluated by the Ocular Surface Disease Index and Dry Eye Questionnaire-5. Information on demographics, exposures, past medical and ocular history, and medications was also collected.Results: The frequency of severe DE symptoms was found to be 43% based on the Ocular Surface Disease Index and 30% based on Dry Eye Questionnaire-5. Risk factors significantly associated with increased DE symptoms included dry mouth and gastrointestinal ulcer medications. With regard to signs, aqueous tear deficiency was a less-frequent finding (22% in our population than evaporative deficiency (94%. Risk factors associated with aqueous tear deficiency were dry mouth and diuretic use. No risk factors were associated with evaporative deficiency. Risk factors associated with meibomian gland dysfunction included old age, male sex, arthritis, and use of an antihypertensive. The only risk factor associated with corneal staining was dry

  11. Mexico.

    Science.gov (United States)

    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

  12. Lattice Wind Description and Characterization of Mexico City Local Wind Events in the 2001–2006 Period

    Directory of Open Access Journals (Sweden)

    Alejandro Salcido

    2015-07-01

    Full Text Available Urban transformation and expansion in Mexico City continuously affect its urban morphology, and therefore the modes of wind circulation inside it and their occurrence probabilities. Knowledge on these topics is an important issue for urban planning and for other urban studies, such as air quality assessment. In this paper, using a lattice wind model at a meso-β scale, we develop a simple description and characterization of Mexico City local wind events that occurred during the period 2001–2006, including an estimation of the occurrence probabilities. This region was modeled as a 2D lattice domain of identical cells, and wind conditions in each cell were described by four wind attributes: the horizontal velocity components, divergence, and vorticity. Models of one and four cells were applied to wind data furnished by the meteorological network of the city. Results include the following: Early morning: low intensity winds (75% from N, NW, W and SW (75%, convergent (93%, with a slight predominance of cyclonic vorticity (54%. Morning and early afternoon: winds from N, NE and E (72% with speeds from 0.5 to 3.5 m/s, slight prevailing of convergent winds (51%, and slight predominance of cyclonic vorticity (57%. Late afternoon and night: winds blowing from N, NW, and S (63% with speeds from 1.5 to 3.5 m/s (66%, convergent (90%, and cyclonic (72%.

  13. Social and Environmental Influences Shaping Risk Factors and Protective Behaviors in two Mexico-US Border Cities

    Science.gov (United States)

    Ramos, Rebeca; Ferreira-Pinto, João B.; Brouwer, Kimberly C.; Ramos, Maria Elena; Lozada, Remedios M.; Firestone-Cruz, Michelle; Strathdee, Steffanie A.

    2009-01-01

    The economic, social, cultural and political milieus that influence HIV risk behaviors along the U.S.- Mexico border are understudied. In an effort to appropriately inform interventions targeting structural influences, we compared injecting drug using populations living in two cities—Ciudad Juárez, Chihuahua and Tijuana, Baja California— situated on the Mexico-U.S. border. These populations presented with similar demographic profiles, but differed significantly in terms of social and environmental influences that can influence both risk and protective factors (e.g., family drug use, migration, drug use patterns). We observed distinct behavioral and structural influences in these two border cities that will require tailored intervention strategies to reduce HIV transmission. PMID:19464228

  14. Prevalence and correlates of client-perpetrated abuse among female sex workers in two Mexico-U.S. border cities.

    Science.gov (United States)

    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.

  15. Reading Comprehension Instruction Practices in Sierra Leone

    NARCIS (Netherlands)

    Hersbach, S.; Denessen, E.J.P.G.; Droop, W.

    2014-01-01

    Aim: In this study an attempt was made to give insight in the way reading comprehension is taught in Sierra Leone. Attention was paid to the didactical strategies and the materials used during reading comprehension instruction. Methodology: Primary school teachers in Sierra Leone (N=43) were

  16. Obesity increases metabolic syndrome risk factors in school-aged children from an urban school in Mexico city.

    Science.gov (United States)

    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. High blood pressure and cardiovascular risk factors in an adult population of Mexico City. Characteristics of the studied population.

    Science.gov (United States)

    Yamamoto-Kimura, L; Zamora-González, J; Huerta-Alvarado, S; Fajardo-Gutiérrez, A; Cardoso-Saldaña, G; Posadas-Romero, C

    1996-01-01

    The present report is a description of the characteristics of a studied population and of the methodology used in a study performed to investigate high blood pressure prevalence and cardiovascular risk factors among the adult population of Mexico City. A cross-sectional study was conducted from January 1991 to March 1992. Random samplings of multiple stages was used and 825 adult subjects were studied in Mexico City. The following measurements were registered: blood pressure, body mass index (BMI), waist-hip ratio (WHR), total cholesterol (TC), triglycerides (TG), high density lipoproteins (HDL-C) and low density lipoproteins (LDL-C), lipoprotein (a) (Lp(a)), glucose and insulin. Personal and family history of cardiovascular illness were investigated, as well as exposure to some risk factors such as smoking, alcohol consumption and sedentarism. The response rate was 86.6%. The prevalence of high blood pressure was 21.1%, and of non-insulin dependent diabetes mellitus was 8.7%. Frequency of dyslipidemia in the studied sample was 24.4% for high TG, 23.6% for low HDL-C, 23.6% for high LDL-C, 14.9% for Lp(a) excess (Lp(a) > or = 30 mg/dl; overweight and obesity were more prevalent among women. The diversity of living conditions among the population of Mexico City was included in the sampling strategy design, not only to register the high blood pressure (HBP) frequency in each stratum but to identify other cardiovascular risk factors which could be decisive in the development of HBP. Regarding the features of the studied population, BMI did not reveal differences among men, but their TG levels were higher and HDL levels lower than those of other populations. In women, the results obtained for BMI, WHR, lipids and lipoproteins were also higher compared with the mean reported for other populations.

  18. Measurements of peroxyacyl nitrates (PANS) in Mexico City: implications for megacity air quality impacts on regional scales

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Cunningham, M. M.; Doskey, P. V.

    Peroxyacyl nitrates (PANs) were measured using gas chromatography with electron capture detection (GC/ECD) in north central Mexico City during February-March of 1997. Peroxyacetyl nitrate (PAN) was observed to exceed 30 ppb during five days of the study, with peroxypropionyl nitrate (PPN) and peroxybutryl nitrate (PBN) reaching 6 and 1 ppb maximum, respectively. Levels of total PANs typically exceeded 10 ppb during the period of measurement and showed a very strong diurnal variation with PANs maximum during the early afternoon and falling to less than 0.1 ppb during the evening hours. These levels of PANs are the highest reported values in North America (and the world) for an urban center, since levels of approximately 30 ppb were reported during the late 1970s in the Los Angeles area (South Coast Air Basin, Tuazon et al., 1978). Hydrocarbon measurements indicate that the levels of olefins, specifically butenes are significant in Mexico City. A time series taken of source indicator hydrocarbons taken before and during a Mexican National Holiday with reduced automobile traffic clearly show that mobile sources of butenes are as important as liquefied petroleum gas. Observations of 10-40 ppb C methyl- t-butyl ether (MTBE) are consistent with MTBE/gasoline fuel usage as a source of isobutene and formaldehyde. Both these reactive species can lead to increased oxidant and PAN formation. The strong diurnal profiles of PANs are consistent with regional clearing of the Mexico City air basin on a daily basis. Estimates are given using a simple box model calculation for a number of key primary and secondary pollutant emissions from this megacity on an annual basis. These calculations indicate that megacities can be important sources of both primary and secondary pollutants, and that PANs produced in megacity environments are likely to contribute strongly to regional scale ozone and aerosol productions during long range transport.

  19. Simulation of Mexico City plumes during the MIRAGE-Mex field campaign using the WRF-Chem model

    Directory of Open Access Journals (Sweden)

    X. Tie

    2009-07-01

    Full Text Available The quantification of tropospheric O3 production in the downwind of the Mexico City plume is a major objective of the MIRAGE-Mex field campaign. We used a regional chemistry-transport model (WRF-Chem to predict the distribution of O3 and its precursors in Mexico City and the surrounding region during March 2006, and compared the model with in-situ aircraft measurements of O3, CO, VOCs, NOx, and NOy concentrations. The comparison shows that the model is capable of capturing the timing and location of the measured city plumes, and the calculated variability along the flights is generally consistent with the measured results, showing a rapid increase in O3 and its precursors when city plumes are detected. However, there are some notable differences between the calculated and measured values, suggesting that, during transport from the surface of the city to the outflow plume, ozone mixing ratios are underestimated by about 0–25% during different flights. The calculated O3-NOx, O3-CO, and O3-NOz correlations generally agree with the measured values, and the analyses of these correlations suggest that photochemical O3 production continues in the plume downwind of the city (aged plume, adding to the O3 already produced in the city and exported with the plume. The model is also used to quantify the contributions to OH reactivity from various compounds in the aged plume. This analysis suggests that oxygenated organics (OVOCs have the highest OH reactivity and play important roles for the O3 production in the aging plume. Furthermore, O3 production per NOx molecule consumed (O3 production efficiency is more efficient in the aged plume than in the young plume near the city. The major contributor to the high O3 production efficiency in the aged plume is the

  20. Meeting Report: Institute for Social Security and Services for State Workers (ISSSTE on Acute Lymphoblastic Leukaemia, Mexico City, Mexico, 3rd to 4th October 2016

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    Alvarado Ibarra Martha

    2017-06-01

    Full Text Available From October 3 to 4, 2016, the fourth meeting of haematologists who belonged to the institute for social security and services for state workers (ISSSTE was held, the meeting was held in Mexico City, Mexico. Attending this working meeting, medical fellows of the specialty of Haematology and Paediatric Haematology, as well as attached doctors of both specialties that work in different hospitals in Mexico City and the rest of the country, the purpose of the attendees to this consensus was discuss, update, and homogenize the protocols of diagnostic and therapeutic approach in patients with acute lymphoblastic leukaemia of all ages. All participants appreciated the opportunity to participate in one of the most important cooperation projects of the ISSSTE and to be able to offer updated treatment protocols to this population or, failing that, to send them a Medical Center that can provide hospital care as soon as possible. Physicians took advantage of this meeting for the scientific exchange, the discussion on projects in course and were planned the development of other consensuses being the closest the one of lymphomas. As in the previous consensuses that were published in a National magazine. The coordinator of this project raised to the attendees the possibility of a publication in magazines of greater prestige international since in countries like Mexico the cooperative work is not frequent and the group of haematologists belonging to ISSSTE are working towards this goal. This consensus was considered as a very well-organized platform to support the research of young fellows in the specialty to stimulate the team work in protocols of the different haematological pathologies and to inform the world the results achieved in a population of patients attended by the ISSSTE. In agreement with the main objective of this consensus on acute lymphoblastic leukaemia once finished and discussed throughout the haematological group, the coordinator for the

  1. Elemental contents determination in two different zones of Mexico City on the 1987-88 and 1994-95 winters

    International Nuclear Information System (INIS)

    Diaz G, R.V.

    1996-01-01

    During the 1987-1988 and 1994-1995 winters, there were taken samples of aerosols in Mexico City, in two different places, using an integral type of sampler which determines the total amount of suspended particulates; these samples were analyzed by the multi-element analysis technique called PIXE (Proton Induced X-ray Emission). One of the sites corresponds to the Alvaro Obregon area and the other to the Azcapotzalco area (a place near to the18 de Marzo Refinery). There were determined 16 elements, heavy metals, whose concentrations show differences for both sites and periods, standing out for this study the behavior of S, V and Pb. (Author)

  2. Exploring migratory dynamics on HIV transmission: the case of Mexicans in New York City and Puebla, Mexico.

    Science.gov (United States)

    Ruiz, Yumary; Guilamo-Ramos, Vincent; McCarthy, Katharine; Muñoz-Laboy, Miguel A; de Lourdes Rosas López, Maria

    2014-06-01

    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.

  3. Of Lady-killers and ‘Men Dressed As Women’: Soap Opera, Scapegoats and the Mexico City Police Department

    OpenAIRE

    Lewis, Vek

    2008-01-01

    Over two days in October 2005, police in Mexico City conducted a series of raids on male-to-female transgender (travesti) prostitutes working in the streets. The motive of the investigation was not related to sex work at all, but rather, the hunt for a serial killer responsible for the deaths of elderly women between 2003 and 2005. With few leads apart from reports by a couple of eyewitnesses that they had seen ‘a man dressed as a woman’ enter the houses of the victims, the Chief Public Prose...

  4. Popular Health Education and Propaganda in Times of Peace and War in Mexico City, 1890s–1920s

    Science.gov (United States)

    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

  5. Exploring Migratory Dynamics on HIV Transmission: The Case of Mexicans in New York City and Puebla, Mexico

    Science.gov (United States)

    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

  6. Caries dental en escolares del Distrito Federal Dental caries in school children in Mexico City

    Directory of Open Access Journals (Sweden)

    MARÍA ESTHER IRIGOYEN-CAMACHO

    1997-03-01

    Full Text Available Objetivo. Presentar las estimaciones de la prevalencia y la severidad de caries dental, así como las necesidades de tratamiento de la población escolar del Distrito Federal examinada en la encuesta de caries dental que se llevó a cabo en 1988 con la finalidad de obtener datos basales sobre caries en los escolares al inicio del Programa Nacional de Fluoruración de la Sal en México. Material y métodos. La población de estudio fue seleccionada empleando un marco muestral basado en el listado de las escuelas primarias y los jardines de niños registrados por la Secretaría de Educación Pública en 1988. En el examen de la cavidad bucal de los escolares se utilizaron los criterios diagnósticos señalados por la Organización Mundial de la Salud. Resultados. Un total de 4 475 escolares de 5 a 12 años de edad participaron en el estudio. La prevalencia de caries dental en la población alcanzó 90.5%. El índice de necesidades de tratamiento fue elevado (79.6%. El promedio de los índices de caries en los escolares de 12 años de edad fue CPOD= 4.42 (desviación estándar –DE– 3.2 y CPOS= 6.53 (DE 4.8. Conclusiones. Los resultados de la encuesta subrayan la pertinencia de un programa preventivo de amplia cobertura, como el de fluoruración de la sal. Además, muestran que se requiere elaborar estrategias para mejorar el acceso de la población escolar a los servicios odontológicos del sistema de salud en México.Objective. To estimate the prevalence and severity of dental caries and the dental treatment necessities of school children in Mexico City. The studied population was surveyed for dental caries in 1988 to obtain data necessary for the National Program of Salt Fluoridation in Mexico. Material and methods. The population was selected with a sample frame based on a list of Kindergardens and primary schools registered at the Ministry of Public Education in 1988. The oral cavity examination was based on diagnostic criteria marked by the

  7. Cultures of space and collective and participative artistic processes. recent cases in mexico city, bogota and medellin

    Directory of Open Access Journals (Sweden)

    Fernando Escobar Neira

    2012-06-01

    Full Text Available this article covers different aspects related to the spacialization of some cases of collective and participative artistic practices in specific places of three latin american cities: mexico city, bogota and medellin. therefore, the article questions the presence of different social ideologies and representations concerning the artistic field in its local and global dimensions, which establish meanings for the artistic, the political and social matters and, at the same time, fight among themselves when associating with certain contemporary artistic practices and its agents and institutions. in order to do so, it is proposed a focus that, to a certain extent, is separated from art theory and history, placing itself in a constant to and fro movement between the assumptions of artistic practices and social sciences.

  8. Determination of particle size and content of metals in the atmosphere of ZMCM (Metropolitan Zone of Mexico City)

    International Nuclear Information System (INIS)

    Aldape U, F.; Flores M, J.; Diaz, R.V.; Garcia G, R.

    1994-01-01

    Inside the breathable fraction of the atmosphere of Mexico City, the presence of metals in suspended particles, is determined and quantified. The detection was carry out simultaneously in three places of the city, using collectors of the type stacking filter unit (SFU) which allow the separation of particles according to its size. The SFU detectors allow the separation in two size: 'Gross' mass from 2.5 to 1.5 μm and 'fine' mass for particles smallest than 2.5 μm. The analysis of the samples was fulfilled by means of PIXE method. Samples were irradiated with a proton beam, and based in the X-ray spectra the elements were identified and quantified, which allow to establish the temporal behavior of the concentrations per element for gross mass and fine mass in each one of the places of sampling. (Author)

  9. Evaluation of recently-proposed secondary organic aerosol models for a case study in Mexico City

    Directory of Open Access Journals (Sweden)

    K. Dzepina

    2009-08-01

    Full Text Available Recent field studies have found large discrepancies in the measured vs. modeled SOA mass loadings in both urban and regional polluted atmospheres. The reasons for these large differences are unclear. Here we revisit a case study of SOA formation in Mexico City described by Volkamer et al. (2006, during a photochemically active period when the impact of regional biomass burning is minor or negligible, and show that the observed increase in OA/ΔCO is consistent with results from several groups during MILAGRO 2006. Then we use the case study to evaluate three new SOA models: 1 the update of aromatic SOA yields from recent chamber experiments (Ng et al., 2007; 2 the formation of SOA from glyoxal (Volkamer et al., 2007a; and 3 the formation of SOA from primary semivolatile and intermediate volatility species (P-S/IVOC (Robinson et al., 2007. We also evaluate the effect of reduced partitioning of SOA into POA (Song et al., 2007. Traditional SOA precursors (mainly aromatics by themselves still fail to produce enough SOA to match the observations by a factor of ~7. The new low-NOx aromatic pathways with very high SOA yields make a very small contribution in this high-NOx urban environment as the RO2·+NO reaction dominates the fate of the RO2· radicals. Glyoxal contributes several μg m−3 to SOA formation, with similar timing as the measurements. P-S/IVOC are estimated from equilibrium with emitted POA, and introduce a large amount of gas-phase oxidizable carbon that was not in models before. With the formulation in Robinson et al. (2007 these species have a high SOA yield, and this mechanism can close the gap in SOA mass between measurements and models in our case study. However the volatility of SOA produced in the model is too high and the O/C ratio is somewhat lower than observations. Glyoxal SOA helps to bring the O/C ratio of predicted and observed SOA into better

  10. Family context and individual situation of teens before, during and after pregnancy in Mexico City.

    Science.gov (United States)

    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

  11. A case study of ozone production, nitrogen oxides, and the radical budget in Mexico City

    Directory of Open Access Journals (Sweden)

    E. C. Wood

    2009-04-01

    Full Text Available Observations at a mountain-top site within the Mexico City basin are used to characterize ozone production and destruction, nitrogen oxide speciation and chemistry, and the radical budget, with an emphasis on a stagnant air mass observed on one afternoon. The observations compare well with the results of recent photochemical models. 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(PM1 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(PM1 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.

  12. Modeled and observed ozone sensitivity to mobile-source emissions in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Zavala

    2009-01-01

    Full Text Available The emission characteristics of mobile sources in the Mexico City Metropolitan Area (MCMA have changed significantly over the past few decades in response to emission control policies, advancements in vehicle technologies and improvements in fuel quality, among others. Along with these changes, concurrent non-linear changes in photochemical levels and criteria pollutants have been observed, providing a unique opportunity to understand the effects of perturbations of mobile emission levels on the photochemistry in the region using observational and modeling approaches. The observed historical trends of ozone (O3, carbon monoxide (CO and nitrogen oxides (NOx suggest that ozone production in the MCMA has changed from a low to a high VOC-sensitive regime over a period of 20 years. Comparison of the historical emission trends of CO, NOx and hydrocarbons derived from mobile-source emission studies in the MCMA from 1991 to 2006 with the trends of the concentrations of CO, NOx, and the CO/NOx ratio during peak traffic hours also indicates that fuel-based fleet average emission factors have significantly decreased for CO and VOCs during this period whereas NOx emission factors do not show any strong trend, effectively reducing the ambient VOC/NOx ratio.

    This study presents the results of model analyses on the sensitivity of the observed ozone levels to the estimated historical changes in its precursors. The model sensitivity analyses used a well-validated base case simulation of a high pollution episode in the MCMA with the mathematical Decoupled Direct Method (DDM and the standard Brute Force Method (BFM in the 3-D CAMx chemical transport model. The model reproduces adequately the observed historical trends and current photochemical levels. Comparison of the BFM and the DDM sensitivity techniques indicates that the model yields ozone values that increase linearly with

  13. Emission factors of black carbon and co-pollutants from diesel vehicles in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Zavala

    2017-12-01

    Full Text Available Diesel-powered vehicles are intensively used in urban areas for transporting goods and people but can substantially contribute to high emissions of black carbon (BC, organic carbon (OC, and other gaseous pollutants. Strategies aimed at controlling mobile emissions sources thus have the potential to improve air quality and help mitigate the impacts of air pollutants on climate, ecosystems, and human health. However, in developing countries there are limited data on the BC and OC emission characteristics of diesel-powered vehicles, and thus there are large uncertainties in the estimation of the emission contributions from these sources. We measured BC, OC, and other inorganic components of fine particulate matter (PM, as well as carbon monoxide (CO, nitrogen oxides (NOx, sulfur dioxide (SO2, ethane, acetylene, benzene, toluene, and C2-benzenes under real-world driving conditions for 20 diesel-powered vehicles encompassing multiple emission level technologies in Mexico City with the chasing technique using the Aerodyne mobile laboratory. Average BC emission factors ranged from 0.41–2.48 g kg−1 of fuel depending on vehicle type. The vehicles were also simultaneously measured using the cross-road remote sensing technique to obtain the emission factors of nitrogen oxide (NO, CO, total hydrocarbons, and fine PM, thus allowing for the intercomparison of the results from the two techniques. There is overall good agreement between the two techniques and both can identify high and low emitters, but substantial differences were found in some of the vehicles, probably due to the ability of the chasing technique to capture a larger diversity of driving conditions in comparison to the remote sensing technique. A comparison of the results with the US EPA MOVES2014b model showed that the model underestimates CO, OC, and selected VOC species, whereas there is better agreement for NOx and BC. Larger OC / BC ratios were found in comparison to ratios

  14. Modeling the impacts of biomass burning on air quality in and around Mexico City

    Science.gov (United States)

    Lei, W.; Li, G.; Molina, L. T.

    2013-03-01

    The local and regional impacts of open fires and trash burning on ground-level ozone (O3) and fine carbonaceous aerosols in the Mexico City Metropolitan Area (MCMA) and surrounding region during two high fire periods in March 2006 have been evaluated using WRF-CHEM model. The model captured reasonably well the measurement-derived magnitude and temporal variation of the biomass burning organic aerosol (BBOA), and the simulated impacts of open fires on organic aerosol (OA) were consistent with many observation-based estimates. We did not detect significant effects of open fires and trash burning on surface O3 concentrations in the MCMA and surrounding region. In contrast, they had important influences on OA and elemental carbon (EC), increasing primary OA (POA) by ~60%, secondary OA (SOA) by ~22%, total OA (TOA = POA + SOA) by ~33%, and EC by ~22%, on both the local (urban) and regional scales. Although the emissions of trash burning are substantially lower than those from open fires, trash burning made slightly smaller but comparable contributions to OA as open fires did, and exerted an even higher influence on EC. Of the ~22% enhancement in SOA concentrations (equivalent to a ~15% increase in TOA) simulated, about two third was attributed to the open fires and one-third to the trash burning. On the annual basis and taking the biofuel use emissions into consideration, we estimated that open fires, trash burning and biofuel use together contributed about 60% to the loading of POA, 30% to SOA, and 25% to EC in both the MCMA and its surrounding region, of which the open fires and trash burning contributed about 35% to POA, 18% to SOA, and 15% to EC. The estimates of biomass burning impacts in this study may contain considerable uncertainties due to the uncertainties in their emission estimates in magnitude, temporal and spatial distribution, extrapolations and the nature of spot comparison. More observation and modeling studies are needed to accurately assess the

  15. Modeling the impacts of biomass burning on air quality in and around Mexico City

    Directory of Open Access Journals (Sweden)

    W. Lei

    2013-03-01

    Full Text Available The local and regional impacts of open fires and trash burning on ground-level ozone (O3 and fine carbonaceous aerosols in the Mexico City Metropolitan Area (MCMA and surrounding region during two high fire periods in March 2006 have been evaluated using WRF-CHEM model. The model captured reasonably well the measurement-derived magnitude and temporal variation of the biomass burning organic aerosol (BBOA, and the simulated impacts of open fires on organic aerosol (OA were consistent with many observation-based estimates. We did not detect significant effects of open fires and trash burning on surface O3 concentrations in the MCMA and surrounding region. In contrast, they had important influences on OA and elemental carbon (EC, increasing primary OA (POA by ~60%, secondary OA (SOA by ~22%, total OA (TOA = POA + SOA by ~33%, and EC by ~22%, on both the local (urban and regional scales. Although the emissions of trash burning are substantially lower than those from open fires, trash burning made slightly smaller but comparable contributions to OA as open fires did, and exerted an even higher influence on EC. Of the ~22% enhancement in SOA concentrations (equivalent to a ~15% increase in TOA simulated, about two third was attributed to the open fires and one-third to the trash burning. On the annual basis and taking the biofuel use emissions into consideration, we estimated that open fires, trash burning and biofuel use together contributed about 60% to the loading of POA, 30% to SOA, and 25% to EC in both the MCMA and its surrounding region, of which the open fires and trash burning contributed about 35% to POA, 18% to SOA, and 15% to EC. The estimates of biomass burning impacts in this study may contain considerable uncertainties due to the uncertainties in their emission estimates in magnitude, temporal and spatial distribution, extrapolations and the nature of spot comparison. More observation and modeling studies are needed to accurately assess

  16. Atmospheric dry deposition fluxes of trace elements measured in Queretaro City, Mexico

    Science.gov (United States)

    Garcia, R.; Hernandez, R.; Solis, S.; Perez, R.; Hernandez, G.; Morton, O.; Hernandez, E.; Torres, M. C.; Baez, A.

    2012-04-01

    Sampling was made in the southern section of downtown Mexico City. Samples were collected with an Mini-Vol PM10 . Eight different sources were identified for PM10 aerosols: secondary sulfate, wood combustion, fireworks, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The ions SO42-, NO3-, Cl-, Na+, K+, Ca2+, Mg2+ and NH4+,were analyzed by ion chromatography and the trace metals using an atomic absorption spectrometer. The result indicated that SO42- was the most abundant ion and with respect to trace metal. All the trace elements except Mn and V show statistically significant differences between monitoring sites. The Pearson's correlation applied to all data, showed a high correlation among SO42-, NO3- and NH4+, indicating a common anthropogenic origin. In addition the correlation found between Ca2+ and Al indicated a crustal origin. On the other hand, in considering the total sampling period for particles as well as for all the metals, it is appreciable the significant differences between sites and meteorological seasons. The cluster analysis of air back-trajectories employed in the paper is a technique widely used to identify transport patterns and potential sources of both anthropogenic pollution and natural constituents of the atmosphere, including atmospheric aerosols. It is also used to determine how aerosol optical properties observed over the station differ depending on source region and transport pathways In order to gain a better insight into the origin of trace metal and major inorganic ions, a Principal Component Analysis was applied to the results for 6 elements and 8 ions, from the years 2009 and 2010. Further, the statistical analysis demonstrated the adequate selection of the monitoring areas, confirming that main emission source of these atmospheric pollutants is anthropogenic origin. Evidence suggests that the organic and inorganic species are not always internally mixed, especially in the small modes. The

  17. Emission factors of black carbon and co-pollutants from diesel vehicles in Mexico City

    Science.gov (United States)

    Zavala, Miguel; Molina, Luisa T.; Yacovitch, Tara I.; Fortner, Edward C.; Roscioli, Joseph R.; Floerchinger, Cody; Herndon, Scott C.; Kolb, Charles E.; Knighton, Walter B.; Paramo, Victor Hugo; Zirath, Sergio; Mejía, José Antonio; Jazcilevich, Aron

    2017-12-01

    Diesel-powered vehicles are intensively used in urban areas for transporting goods and people but can substantially contribute to high emissions of black carbon (BC), organic carbon (OC), and other gaseous pollutants. Strategies aimed at controlling mobile emissions sources thus have the potential to improve air quality and help mitigate the impacts of air pollutants on climate, ecosystems, and human health. However, in developing countries there are limited data on the BC and OC emission characteristics of diesel-powered vehicles, and thus there are large uncertainties in the estimation of the emission contributions from these sources. We measured BC, OC, and other inorganic components of fine particulate matter (PM), as well as carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), ethane, acetylene, benzene, toluene, and C2-benzenes under real-world driving conditions for 20 diesel-powered vehicles encompassing multiple emission level technologies in Mexico City with the chasing technique using the Aerodyne mobile laboratory. Average BC emission factors ranged from 0.41-2.48 g kg-1 of fuel depending on vehicle type. The vehicles were also simultaneously measured using the cross-road remote sensing technique to obtain the emission factors of nitrogen oxide (NO), CO, total hydrocarbons, and fine PM, thus allowing for the intercomparison of the results from the two techniques. There is overall good agreement between the two techniques and both can identify high and low emitters, but substantial differences were found in some of the vehicles, probably due to the ability of the chasing technique to capture a larger diversity of driving conditions in comparison to the remote sensing technique. A comparison of the results with the US EPA MOVES2014b model showed that the model underestimates CO, OC, and selected VOC species, whereas there is better agreement for NOx and BC. Larger OC / BC ratios were found in comparison to ratios measured in California using

  18. Anthropological Approaches to the Study of Housing Areas: Lessons from Oaxaca City, Mexico.

    Science.gov (United States)

    Murphy, Arthur D.

    The anthropological study of the city's role in the evolution of human systems requires the use of both macro and micro levels of analysis. From the macro perspective, the city is viewed as part of a wider complex society, while from the micro point of view, the city provides the context for understanding specific human institutions or processes…

  19. Seasonal variation of atmospheric lead levels in three sites in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Rosas, Irma; Belmont, Raul; Jauregui, Ernesto [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico)

    1995-10-01

    Atmospheric lead concentrations associated to particles smaller than 10 {mu}m were measured in Mexico City, to establish changes of levels of this pollutant in three sites (industrial, commercial and residential) for 1990-1991. Moreover, an attempt was made to establish a possible link between this airborne pollutant and blood lead levels reported in children and women living near the sampling sites. A marked gradient in atmospheric lead from North to South is observed with higher and more variable mean lead values in the northern site where industry is located. Lead concentrations and their corresponding variability gradually decrease (from about 1.2 to 0.5 {mu}g m-3) toward the southern suburbs. Moreover, these values are significantly higher during the dry season than in the wet season when a marked washout effect if observed. However, the quarterly averages recorded during the sampling time do not exceed the international standard (1.5 {mu}g m-3). Lead concentrations and corresponding PM{sub 1}0 values showed a significant correlation. This results shows that lead is associated to the fine fraction of airborne particles, with high proportion of them deposited in the respiratory tract. A substantial abatement in levels of atmospheric lead is observed in 1991 with respect to the previous year. This may be explained by the introduction of improved quality gasoline in the capital city. In spite of this measure more than 30% of the evaluated population in 1991 presented blood-lead levels> 10 {mu}g dL-1. [Spanish] Durante 1991 se evaluaron en tres sitios (industrial, comercial y residencial), las concentraciones de plomo atmosferico asociado a particulas menores de 10 {mu}m, con el objeto de establecer los cambios en los niveles de este contaminante. Ademas, se trato de establecer la posible relacion de este contaminante con los niveles de plomo en sangre citados para ninos y mujeres que viven en los alrededores de los sitios de muestreo. Se observo un marcado

  20. Observed trends in ground-level O3 in Monterrey, Mexico, during 1993-2014: comparison with Mexico City and Guadalajara

    Science.gov (United States)

    Hernández Paniagua, Iván Y.; Clemitshaw, Kevin C.; Mendoza, Alberto

    2017-07-01

    Here, we present an assessment of long-term trends in O3 and odd oxygen (O3 + NO2) at the industrial Monterrey metropolitan area (MMA) in NE Mexico. Diurnal amplitudes in Ox (AVd) are used as a proxy for net O3 production, which is influenced by the NO2 photolysis rate. No significant differences in the AVd are observed between weekends and weekdays, although the largest AVd values are observed at sites downwind of industrial areas. The highest O3 mixing ratios are observed in spring, with minimum values in winter. The largest annual variations in O3 are typically observed downwind of the MMA, with the lowest variations generally recorded in highly populated areas and close to industrial areas. A wind sector analysis of mixing ratios of O3 precursors revealed that the dominant sources of emissions are located in the industrial regions within the MMA and surrounding area. Significant increasing trends in O3 in spring, summer, and autumn are observed depending on site location, with trends in annual averages ranging between 0.19 and 0.33 ppb yr-1. Overall, from 1993 to 2014, within the MMA, O3 has increased at an average rate of 0.22 ppb yr-1 (p Mexico City metropolitan area (MCMA) for the same period. No clear trend is observed from 1996 to 2014 within the Guadalajara metropolitan area (GMA).

  1. Unpacking Mobility, Sex Trafficking, and HIV Vulnerability in Two Mexico-U.S. Border Cities

    OpenAIRE

    Goldenberg, Shira Miriam

    2011-01-01

    Background: Sex trafficking is a human rights abuse that carries particularly negative health and social consequences, including HIV and sexually transmitted infections (STIs). While HIV/STI infection and sex trafficking have been linked in Asia, the context of these associations and their applicability in Mexico is poorly understood.Aims: Aims of this dissertation were to (1) Critically review evidence linking mobility, trafficking, and HIV vulnerability in Mexico and Central America; (2) Ex...

  2. Geo-social and health disparities among persons with disabilities living in Monterrey, Nuevo Leon and Dallas, Texas.

    Science.gov (United States)

    Nikolova, Silviya P; Small, Eusebius; Campillo, Claudia

    2015-07-01

    In low and high income countries alike, disability exacerbates social, economic, and health disparities, in spite of their differences. This study seeks to identify factors that predict the circumstances people with disabilities face, including poverty. A cross-sectional study design was employed using census track level data for the cities of Monterrey, Nuevo Leon, and Dallas, Texas, from Mexico 2010 and USA 2000 census data collections. Two methods, spatial autocorrelation and geographically weighted regression were used to identify spatial patterns of disability and to explore the relation between disability and context-specific socio-demographic factors. Results indicated that people with disabilities living below the poverty line experience high segregation levels in the semi-central zones of Dallas. In Monterrey, people with disabilities clustered in central areas of the city. A Geographically Weighted Regression (GWR) from both data analyses reported high goodness of fit (R ≥ 0.8 for Dallas data and R ≥ 0.7 for Monterrey data, respectively) and predictability of disability prevalence when social disadvantage factors such as unemployment, housing insecurity, household living conditions, and lack of education were present. The divergent and sometimes conflicting trends in practices and policies addressing disability in low and high income environments renders a reexamination of the framework of disability. An understanding of local characteristics joins a grounded socio-cultural understanding of the various contexts that shape location-based social networks and political decisions in providing such an analysis. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Potential prescription patterns and errors in elderly adult patients attending public primary health care centers in Mexico City

    Directory of Open Access Journals (Sweden)

    José Antonio Corona-Rojo

    2009-08-01

    Full Text Available José Antonio Corona-Rojo1, Marina Altagracia-Martínez1, Jaime Kravzov-Jinich1, Laura Vázquez-Cervantes1, Edilberto Pérez-Montoya2, Consuelo Rubio-Poo31Division of Biological Sciences and Health, Metropolitan Autonomous University, Campus Xochimilco (UAM-X, Xochimilco, México; 2National Polytechnical Institute (IPN, México DF; 3Faculty of Higher Studies – Zaragoza (FES-Zaragoza, National Autonomous University of México (UNAM, México City, MéxicoIntroduction: Six out of every 10 elderly persons live in developing countries.Objective: To analyze and assess the drug prescription patterns and errors in elderly outpatients attending public health care centers in Mexico City, Mexico.Materials and methods: A descriptive and retrospective study was conducted in 2007. Fourteen hundred prescriptions were analyzed. Prescriptions of ambulatory adults aged >70 years who were residents of Mexico City for at least two years were included. Prescription errors were divided into two groups: (1 administrative and legal, and (2 pharmacotherapeutic. In group 2, we analyzed drug dose strength, administration route, frequency of drug administration, treatment length, potential drug–drug interactions, and contraindications. Variables were classified as correct or incorrect based on clinical literature. Variables for each drug were dichotomized as correct (0 or incorrect (1. A Prescription Index (PI was calculated by considering each drug on the prescription. SPSS statistical software was used to process the collected data (95% confidence interval; p < 0.05.Results: The drug prescription pattern in elderly outpatients shows that 12 drugs account for 70.72% (2880 of prescribed drugs. The most prescribed drugs presented potential pharmacotherapeutic errors (as defined in the present study. Acetylsalicylic acid–captopril was the most common potential interaction (not clinically assessed. Potential prescription error was high (53% of total prescriptions. Most

  4. [Flu symptoms and preventive measures practiced by the inhabitants of Mexico City during the AH1N1 influenza epidemic].

    Science.gov (United States)

    Cruz-Licea, Verónica; González-Domínguez, Fernando; Avila, Guillermina; Flisser, Ana

    2013-01-01

    To know the frequency of flu symptoms and describe preventive measures practiced by the inhabitants of Mexico City during the AH1N1 epidemic. A cross-sectional design was used and a survey containing demographic and health information was conducted in August and September 2009 in a sample of 4003 randomly selected people living in Mexico City. Referred flu symptoms were: 29% running nose, 25% cough, 25% throat infection, 17% muscle and joint pain, 10% respiratory problems, and 7% fever. Also 16% said having hypertension, 10% diabetes, and 2% morbid obesity. Among the preventive measures, 74% washed hands, 32% covered the nose and mouth with the forearm when coughing or sneezing, 28% used sanitizer gel five times a day in average, and 47% did not greet with a kiss or handshake. Almost all the population followed preventive measures and did not show high percentages of influenza symptoms. Useful elements for prevention were identified, such as the frequency of seasonal influenza vaccination, self-medication, and living with a person diagnosed with AH1N1. It is important to continue with mass communication to strengthen adequate hygiene and health measures.

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

    Science.gov (United States)

    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.

  6. Comparison of lead levels in human permanent teeth from Strasbourg, Mexico City, and rural zones of Alsace

    Energy Technology Data Exchange (ETDEWEB)

    Frank, R.M.; Sargentini-Maier, M.L.; Turlot, J.C.; Leroy, M.J. (Univ. Louis Pasteur, Strasbourg (France))

    1990-01-01

    A comparative study of the mean lead concentrations in enamel and dentin of human premolars and permanent molars was conducted by means of a systematic sampling procedure with energy-dispersive x-ray fluorescence analysis. In a first series of analyses, no significant statistical differences in mean lead concentrations at various levels of enamel and dentin were noted between young patients of Strasbourg and those of small villages of Alsace, nor between elderly patients living in these two locations, despite the fact that motor traffic was significantly lower in the rural zones. However, in both locations, a significantly higher concentration of lead was observed in enamel and dentin in relation to age. In a second series of analyses, the mean lead concentrations of both dental hard tissues of premolars and permanent molars of young individuals from Strasbourg, rural Alsace, and Mexico City were compared. Significantly higher mean lead concentrations were found in enamel and dentin samples from Mexico City. This was most evident for inner coronal dentin (5.7 and 6.1 times greater than in teeth of Strasbourg and rural zones of Alsace, respectively) and for pulpal root dentin (6.9 and 8.9 times greater than in teeth of Strasbourg and rural zones of Alsace). It is proposed that the higher lead concentrations are related to the higher lead content of motor gasoline and to more intense traffic conditions. The dental hard tissues appear to be of value for the study of environmental lead pollution.

  7. A comparative simple method for human bioclimatic conditions applied to seasonally hot/warm cities of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tejeda Martinez, A. [Universidad Veracruzana, Xalapa, Veracruz (Mexico); Garcia Cueto, O.R. [Universidad Autonoma de Baja California, Mexicali, B.C. (Mexico)

    2002-01-01

    The climate of a region is an environmental resource with important implications for things such as thermal comfort, health and productivity of the population. In this work, the bioclimatic comfort was evaluated for seven seasonally warm/hot cities of Mexico by means of the following current indexes: Discomfort Index, Enthalpy Index and Heat Strain Index. Also, the periods during which it is necessary to use air conditioning in the studied cities were calculated from estimated global radiation and hourly data of temperature and relative humidity which made it possible to establish them with high precision. Finally, the useful of the Heat Strain Index is shown. It is a simple index needing available meteorological data to compare bioclimatic conditions of similar sites. [Spanish] El clima regional tiene implicaciones en el confort, la salud y la productividad de la poblacion. En este articulo se presentan las evaluaciones bioclimaticas comparativas de siete ciudades calidas de Mexico. Se aplicaron los indices bioclimaticos de disconfort, entalpia y esfuerzo frente al calor. Se calcularon los periodos para los cuales es necesario el uso de aire acondicionado, a partir de estimaciones de radiacion solar global y de temperatura y humedad horarias medias mensuales. Finalmente se muestra la utilidad y calidad del Indice de esfuerzo frente al calor, el cual requiere solo de datos climatologicos comunes para poder comparar condiciones bioclimaticas de sitios similares.

  8. The potential of volunteered geographic information to investigate peri-urbanization in the conservation zone of Mexico City.

    Science.gov (United States)

    Heider, Katharina; Lopez, Juan Miguel Rodriguez; Scheffran, Jürgen

    2018-03-14

    Due to the availability of Web 2.0 technologies, volunteered geographic information (VGI) is on the rise. This new type of data is available on many topics and on different scales. Thus, it has become interesting for research. This article deals with the collective potential of VGI and remote sensing to detect peri-urbanization in the conservation zone of Mexico City. On the one hand, remote sensing identifies horizontal urban expansion, and on the other hand, VGI of ecological complaints provides data about informal settlements. This enables the combination of top-down approaches (remote sensing) and bottom-up approaches (ecological complaints). Within the analysis, we identify areas of high urbanization as well as complaint densities and bring them together in a multi-scale analysis using Geographic Information Systems (GIS). Furthermore, we investigate the influence of settlement patterns and main roads on the peri-urbanization process in Mexico City using OpenStreetMap. Peri-urbanization is detected especially in the transition zone between the urban and rural (conservation) area and near main roads as well as settlements.

  9. Characterization of Fine Particulate Matter (PM) and Secondary PM Precursor Gases in the Mexico City Metropolitan Area

    Science.gov (United States)

    Molina, Luisa T.; Volkamer, Rainer; de Foy, Benjamin; Lei, Wenfang; Zavala, Miguel; Velasco, Erik; Molina; Mario J.

    2008-10-31

    This project was one of three collaborating grants funded by DOE/ASP to characterize the fine particulate matter (PM) and secondary PM precursors in the Mexico City Metropolitan Area (MCMA) during the MILAGRO Campaign. The overall effort of MCMA-2006, one of the four components, focused on i) examination of the primary emissions of fine particles and precursor gases leading to photochemical production of atmospheric oxidants and secondary aerosol particles; ii) measurement and analysis of secondary oxidants and secondary fine PM production, with particular emphasis on secondary organic aerosol (SOA), and iii) evaluation of the photochemical and meteorological processes characteristic of the Mexico City Basin. The collaborative teams pursued the goals through three main tasks: i) analyses of fine PM and secondary PM precursor gaseous species data taken during the MCMA-2002/2003 campaigns and preparation of publications; ii) planning of the MILAGRO Campaign and deployment of the instrument around the MCMA; and iii) analysis of MCMA-2006 data and publication preparation.

  10. Correlates of subjective transportation deficiency among older adults attending outpatient clinics in a tertiary care hospital in Mexico City.

    Science.gov (United States)

    Navarrete-Reyes, Ana Patricia; Medina-Rimoldi, Carlos Tonatiuh; Avila-Funes, José Alberto

    2017-11-01

    Older adults frequently report problems of transportation. Little is known about the correlates of transportation deficiency in Latin America. Therefore, the aim of the present study was to determine the correlates of subjective transportation deficiency (STD) among community-dwelling older adults attending a tertiary care hospital in Mexico City. Cross-sectional study of 228 participants aged ≥70 years being followed in any of the outpatient clinics of a tertiary care hospital in Mexico City. Data were obtained through a structured questionnaire. Univariate and multivariate logistic regression analyses were carried out in order to identify the correlates of STD. The mean age of the participants was 79.8 years (SD 6.4) and 67.1% were women. STD was present in 46% of participants. The multivariate logistic regression model showed that female sex, illiteracy, mobility disability and the use of an assistive walking device had an independent and statistically significant association with STD. Female sex, illiteracy, mobility disability and the use of an assistive walking device were independent correlates of STD in the present study. Identifying the frequency and correlates of transportation deficiency in vulnerable populations will allow for the identification and implementation of useful public policies, as well as for the optimization of prevention and treatment strategies in an attempt to preserve mobility and autonomy, especially in low- and middle-income countries where previous work on transportation deficiency is lacking. Geriatr Gerontol Int 2017; 17: 1893-1898. © 2017 Japan Geriatrics Society.

  11. Comparison of lead levels in human permanent teeth from Strasbourg, Mexico City, and rural zones of Alsace

    International Nuclear Information System (INIS)

    Frank, R.M.; Sargentini-Maier, M.L.; Turlot, J.C.; Leroy, M.J.

    1990-01-01

    A comparative study of the mean lead concentrations in enamel and dentin of human premolars and permanent molars was conducted by means of a systematic sampling procedure with energy-dispersive x-ray fluorescence analysis. In a first series of analyses, no significant statistical differences in mean lead concentrations at various levels of enamel and dentin were noted between young patients of Strasbourg and those of small villages of Alsace, nor between elderly patients living in these two locations, despite the fact that motor traffic was significantly lower in the rural zones. However, in both locations, a significantly higher concentration of lead was observed in enamel and dentin in relation to age. In a second series of analyses, the mean lead concentrations of both dental hard tissues of premolars and permanent molars of young individuals from Strasbourg, rural Alsace, and Mexico City were compared. Significantly higher mean lead concentrations were found in enamel and dentin samples from Mexico City. This was most evident for inner coronal dentin (5.7 and 6.1 times greater than in teeth of Strasbourg and rural zones of Alsace, respectively) and for pulpal root dentin (6.9 and 8.9 times greater than in teeth of Strasbourg and rural zones of Alsace). It is proposed that the higher lead concentrations are related to the higher lead content of motor gasoline and to more intense traffic conditions. The dental hard tissues appear to be of value for the study of environmental lead pollution

  12. The role of a peri-urban forest on air quality improvement in the Mexico City megalopolis

    International Nuclear Information System (INIS)

    Baumgardner, Darrel; Varela, Sebastian; Escobedo, Francisco J.; Chacalo, Alicia; Ochoa, Carlos

    2012-01-01

    Air quality improvement by a forested, peri-urban national park was quantified by combining the Urban Forest Effects (UFORE) and the Weather Research and Forecasting coupled with Chemistry (WRF-Chem) models. We estimated the ecosystem-level annual pollution removal function of the park’s trees, shrub and grasses using pollution concentration data for carbon monoxide (CO), ozone (O 3 ), and particulate matter less than 10 microns in diameter (PM 10 ), modeled meteorological and pollution variables, and measured forest structure data. Ecosystem-level O 3 and CO removal and formation were also analyzed for a representative month. Total annual air quality improvement of the park’s vegetation was approximately 0.02% for CO, 1% for O 3, and 2% for PM 10 , of the annual concentrations for these three pollutants. Results can be used to understand the air quality regulation ecosystem services of peri-urban forests and regional dynamics of air pollution emissions from major urban areas. - Highlights: ► Air quality regulation functions and ecosystem structure of a peri-urban forest in Mexico were quantified. ► Air pollution removal-formation dynamics were estimated using the UFORE and WRF-Chem models. ► Peri-urban forests positively contributed to air qualtiy improvement in Mexico City. ► Results can be used to quantify the ecosystem services of peri-urban forests. - Coupled models estimated air quality improvement and pollution removal-formation by peri-urban forest ecosystems in the Mexico City airshed.

  13. Evaluation of equipment performance, patient dose, imaging quality, and diagnostic coincidence in five Mexico City mammography services.

    Science.gov (United States)

    Brandan, María-Ester; Ruiz-Trejo, César; Verdejo-Silva, Maricela; Guevara, Martha; Lozano-Zalce, Horacio; Madero-Preciado, Luis; Martín, Julia; Noel-Etienne, Louise-Marie; Ramírez-Arias, José-Luis; Soto, Jesús; Villaseñor, Yolanda

    2004-01-01

    Regulations concerning the use of x-rays in medical diagnoses were published in Mexico in 1997. In this work, we evaluate technical aspects of mammography services in the Mexico City area and radiation dose and coincidence between the radiological interpretation by the institution radiologist and by a panel of experts. Following methodology proposed by the American College of Radiology and the European Community among others, we have evaluated the performance of six mammography systems in Mexico City public and private services. The studied services carry out approximately one half of the mammography studies in the capital's metropolitan area. The systems comply with 53-82% of a total of 31 applied quality control tests and measurements, which include the mammography unit, x-ray generation, collimation, automatic exposure control, compression devices, grid and image receptor, film processing, darkroom, viewboxes, dose, film rejection, and image quality. The elements that most frequently fail are film processing, darkroom, and light boxes; average ACR phantom score is 11.2 (9.5, 12.0); mean average glandular dose measured with the phantom is 1.00 (0.71-1.15) mGy, and measured in patients is 1.75 (0.3, 4.9) mGy; coincidence between radiologic reports (BI-RADS) by the institution radiologist and a panel of experts is obtained in 35% of studied cases. Statistical analysis of results indicated that the level of equipment performance is correlated with image quality, image quality estimated by the panel of radiologists is correlated with phantom score, and coincidence in clinical mammography reports is not correlated with equipment performance and appears to depend on the radiologist's experience.

  14. Vehicle fleet emissions of black carbon, polycyclic aromatic hydrocarbons, and other pollutants measured by a mobile laboratory in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Jiang

    2005-01-01

    Full Text Available Black carbon (BC and polycyclic aromatic hydrocarbons (PAHs are of concern due to their effects on climate and health. The main goal of this research is to provide the first estimate of emissions of BC and particle-phase PAHs (PPAHs from motor vehicles in Mexico City. The emissions of other pollutants including carbon monoxide (CO, oxides of nitrogen (NOx, volatile organic compounds (VOCs, and particulate matter of diameter 2.5 μm and less (PM2.5 are also estimated. As a part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003, a mobile laboratory was driven throughout the city. The laboratory was equipped with a comprehensive suite of gas and particle analyzers, including an aethalometer that measured BC and a photoionization aerosol sensor that measured PPAHs. While driving through traffic, the mobile lab continuously sampled exhaust plumes from the vehicles around it. We have developed a method of automatically identifying exhaust plumes, which are then used as the basis for calculation of fleet-average emissions. In the approximately 75 h of on-road sampling during the field campaign, we have identified ~30 000 exhaust measurement points that represent a variety of vehicle types and driving conditions. The large sample provides a basis for estimating fleet-average emission factors and thus the emission inventory. Motor vehicles in the Mexico City area are estimated to emit 1700±200 metric tons BC, 57±6 tons PPAHs, 1 190 000±40 000 tons CO, 120 000±3000 tons NOx, 240 000±50 000 tons VOCs, and 4400±400 tons PM2.5 per year, not including cold start emissions. The estimates for CO, NOx, and PPAHs may be low by up to 10% due to the slower response time of analyzers used to measure these species. Compared to the government's official motor vehicle emission inventory for the year 2002, the estimates for CO, NOx, VOCs, and PM2.5 are 38% lower, 23% lower, 27% higher, and 25% higher, respectively. The

  15. Breast cancer quality of life evaluation in Mexican Women at La Raza Hospital, Mexico City: A preliminary approach

    Directory of Open Access Journals (Sweden)

    Jacobo Alejandro Gómez-Rico

    2008-11-01

    Full Text Available Jacobo Alejandro Gómez-Rico1, Marina Altagracia-Martínez1, Jaime Kravzov-Jinich1, Rosario Cárdenas-Elizalde1, Juan Carlos Hinojosa-Cruz2, Consuelo Rubio-Poo31Departments of Biological Systems and Healthcare, Biological and Health Sciences Division (DCBS, Universidad Autónoma Metropolitana–Xochimilco (UAM-X, Xochimilco, Mexico; 2La Raza Hospital of the Mexican Social Security Institute (IMSS, Mexico City, Mexico; 3Universidad Nacional Autónoma de México (UNAM, Faculty of Professional Studies, Zaragoza (FES-Zaragoza, MexicoAbstract: Breast cancer (BC is the second leading cause of death among Mexican women over 40 years of age. This study aimed to identify and examine the effects of cancer stage and surgical treatment on the quality of life (QOL of Mexican women with early stage breast cancer (ESBC treated with either modified radical mastectomy (MRM or breast conservative surgery (BCS, plus adjuvant chemotherapy. The QLQ-C30 and QLQ BR-23 questionnaires were used to assess QOL. Sociodemographic characteristics and clinical factors of 102 women with early BC were also evaluated; analysis of variance (ANOVA was performed and a statistical significance of p < 0.05 was assumed. Most women were of reproductive age. Meaningful differences in QOL as a result of surgical treatment, in women receiving BCS compared with those receiving MRM, were limited to body image. We conclude that MRM and BCS are essentially equivalent choices in terms of QOL, with the exception of the impact on body image. In general, women who received BCS had a better perceived QOL.Keywords: quality of life, breast cancer, Mexican women

  16. [Cardiac manifestations in the acute phase of Kawasaki disease in a third level children's hospital in Mexico City].

    Science.gov (United States)

    Garrido-García, Luis Martín; Peña-Juárez, Rocío Alejandra; Yamazaki-Nakashimada, Marco Antonio

    2018-04-09

    To describe the cardiac manifestations in the acute phase of patients with Kawasaki disease treated in a third level Children's hospital in Mexico City, Mexico. A cross-sectional study was conducted in patients with a diagnosis of Kawasaki disease treated in this hospital from August 1995 to December 2016. Information included patient demographics, clinical features, treatment used, electrocardiographic findings, extra-coronary echocardiographic findings, and the development of coronary artery aneurysms in the acute phase of the disease. The study included 508 cases of Kawasaki disease, with a mean age at diagnosis of 37.64±35.56 months (range from 2 to 200 months). Almost two-thirds (65.4%) of the patients were male, with a male/female ratio of 1.88:1. Complete Kawasaki disease was diagnosed in 79.2% of cases. Almost all cases (92.4%) received intravenous immunoglobulin. Twenty-eight patients (5.5%) developed arrhythmias, ST changes developed in 29 patients (5.6%), and 5 patients presented with ischaemic changes. In the initial echocardiographic evaluation, 51 patients (9.9%) were diagnosed with myocarditis, 72 patients (14.0%) with pericarditis and 77 cases (15.0%) developed pericardial effusion. Coronary artery anomalies were detected in 169 cases (32.9%). 32 cases were diagnosed as giant coronary aneurysms. Four patients died from cardiac complications in the acute phase of the disease. There has been an increase in the diagnosis of Kawasaki disease in Mexico. They presented with more cardiac complications than reported in literature. An increased knowledge of Kawasaki disease is required in Mexico in order to establish the cardiac outcomes of this group of patients. Copyright © 2018 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

  17. Concepciones de salud en mujeres que trabajan en el sector formal e informal de la ciudad de León, Nicaragua (Health concepts in women working in the formal and informal sector of the city of Leon, Nicaragua

    Directory of Open Access Journals (Sweden)

    Arlen Soto Vanegas

    2012-07-01

    Full Text Available Este artículo tiene como propósito dar a conocer cómo las mujeres de la ciudad de León-Nicaragua conciben, conceptualizan y describen la salud desde su propio contexto. Se realizó un estudio cualitativo con siete grupos de mujeres trabajadoras en la economía formal e informal. Por medio de un análisis de contenido y del discurso se identificaron cinco concepciones de salud: 1.Tradicional o campesina, 2.Maternal, 3.Social, 4.Equilibrio y 5.Biomédica. El conocimiento de estas concepciones podría ser utilizado para ajustar culturalmente los programas de prevención y promoción de salud en atención primaria en el país.ABSTRACTThis paper pretends to demonstrate how women in Leon, Nicaragua conceive, conceptualize and describe health from their own context. A qualitative study was conducted with seven groups of women workers in the formal and informal economy. Through a content and discourse analysis five health concepts were identified: 1. Traditional or peasant, 2.Maternal, 3.Social, 4.Equilibrium and 5.Biomedic. Knowledge of these health concepts could be used to adjust culturally prevention programs and health promotion in primary health care in the country.

  18. Application of neural networks to obtain the site response in Mexico City

    Directory of Open Access Journals (Sweden)

    Vargas J. Carlos A.

    2003-08-01

    Full Text Available

    We have implemented a neural network of three hidden layers with 40 neurons each layer to be used as soil/rock transfer functions for two stations in Mexico City. The net was trained with supervised learning through input and output vectors of accelerations (twelve records, from five seismic events from Guerrero and Puebla, 5.8 M 7.3, and tested with three records not taken in account in the training. The results in the frequency domain are good, finding a seismic amplification between 0.2 to 5 Hz for the Lake zone. In the time domain we obtain results that are not coincident. Due to the data and the complex of the phenomena, it is necessary to apply this tool using more records for the training net, so the phenomena can be learned better through reliable database.

    Hemos implementado una red neuronal de tres capas escondidas con 40 neuronas por capa para ser usada como funciones de trasferencia suelo/roca en dos estaciones acelerométricas en Ciudad de México. La red fue entrenada con entrenamiento supervisado por medio de vectores de aceleración de entrada y salida (doce registros de cinco eventos sísmicos localizados en la costa de Guerrero y uno al sur de Puebla, 5, 8 M 7, 3, y probada con tres registros no tornados en cuenta en el entrenamiento de la red. Los resultados obtenidos en el dominio de la frecuencia son bastante buenos, encontrándose una amplificación sísmica entre 0,2 a 5 Hz para la zona de Lago (estación RMCS. En el dominio del tiempo obtuvimos resultados que no son coincidentes.

    Characterization of Fine Particulate Matter (PM) and Secondary PM Precursor Gases in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Charles E. Kolb

    2008-03-31

    This project was one of three collaborating grants designed to understand the atmospheric chemistry and aerosol particle microphysics impacting air quality in the Mexico City Metropolitan Area (MCMA) and its urban plume. The overall effort, titled MCMA- 2006, focused on: 1) the primary emissions of fine particles and precursor gases leading to photochemical production of atmospheric oxidants and secondary aerosol particles and 2) the measurement and analysis of secondary oxidants and secondary fine particular matter (PM) production, with particular emphasis on secondary organic aerosol (SOA). MCAM-2006 pursued it goals through three main activities: 1) performance and publication of detailed analyses of extensive MCMA trace gas and fine PM measurements made by the collaborating groups and others during earlier MCMA field campaigns in 2002 and 2003; 2) deployment and utilization of extensive real-time trace gas and fine PM instrumentation at urban and downwind MCMA sites in support of the MAX-Mex/MILAGRO field measurements in March, 2006; and, 3) analyses of the 2006 MCMA data sets leading to further publications that are based on new data as well as insights from analysis and publication of the 2002/2003 field data. Thirteen archival publications were coauthored with other MCMA-2003 participants. Documented findings included a significantly improved speciated emissions inventory from on-road vehicles, a greatly enhanced understanding of the sources and atmospheric loadings of volatile organic compounds, a unique analysis of the high fraction of ambient formaldehyde from primary emission sources, a much more extensive knowledge of the composition, size distributions and atmospheric mass loadings of both primary and secondary fine PM, including the fact that the rate of MCMA SOA production greatly exceeded that predicted by current atmospheric models, and evaluations of significant errors that can arise from standard air quality monitors for ozone and nitrogen

  19. Aerosol radiative effects on the meteorology and distribution of pollutants in the Mexico City Metropolitan Area during MCMA-2006/MILAGRO Campaign

    Science.gov (United States)

    Li, Guohui; Bei, Naifang; Molina, Luisa

    2013-04-01

    Aerosols scatter or absorb incoming solar radiation, perturb the temperature structure of the atmosphere, and impact meteorological fields and further the distribution of gas phase species and aerosols. In the present study, the aerosol radiative effects on the meteorology and photochemistry in the Mexico City Metropolitan Area (MCMA) are investigated using the WRF-CHEM model during the period from March 24th to 29th associated with the MILAGRO-2006 campaign. Aerosols decrease incoming solar radiation by up to 20% and reduce the surface temperature by up to 0.5 °C due to scattering and absorbing the incoming solar radiation in Mexico City. The absorption of black carbon aerosols can also enhance slightly the temperature in the planetary boundary layer (PBL). Generally, the change of the PBL height in the city is less than 200 m during daytime due to the aerosol-induced perturbation of temperature profile. Wind fields are also adjusted with the variation of temperatures, but all the aerosol-induced meteorological changes cannot significantly influence the distribution of pollutants in the city. In addition, when convective events occur in the city, the aerosol radiative effects reduce the convective available potential energy (CAPE) and the convective precipitation is generally decreased. Further studies still need to be performed to evaluate the aerosol indirect effect on precipitation in Mexico City.

  1. Analysis of Visible/SWIR surface reflectance ratios for aerosol retrievals from satellite in Mexico City urban area

    Directory of Open Access Journals (Sweden)

    A. D. de Almeida Castanho

    2007-10-01

    Full Text Available The surface reflectance ratio between the visible (VIS and shortwave infrared (SWIR radiation is an important quantity for the retrieval of the aerosol optical depth (τa from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS τa retrieval uses the surface reflectance in the SWIR band (2.1 µm, where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 µm and red (0.66 µm bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA using MODIS radiances at 0.66 µm and 2.1 µm. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol depth and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of τa in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06 for scattering angles <140° and goes up to 0.77±0.06 for higher ones. The average ratio for non-urban sites was significantly lower (approximately 0.55. In fact, this ratio strongly depends on differences in urbanization levels (i.e. relative urban to vegetation proportions and types of surface materials. The aerosol optical depth retrieved from MODIS radiances at a spatial resolution of 1.5 km×1.5 km and averaged within 10×10 km boxes were compared with collocated 1-h τa averaged from sun-photometer measurements. The use of the new RED

  2. Effect of hydrocarbons and nitrogen oxides on ozone formation in smog chambers exposed to solar irradiance of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval F, J; Marroquin de la R, O; Jaimes L, J. L; Zuniga L, V. A; Gonzalez O, E; Guzman Lopez-Figueroa, F [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2001-01-01

    Outdoor smog chambers experiments were performed on air to determine the answer of maximum ozone levels, to changes in the initial hydrocarbons, HC, and nitrogen oxide NO{sub x}. These captive-air experiments under natural irradiation were carried out. Typically, eight chambers were filled with Mexico city air in the morning. In some of those chambers, the initial HC and/or Nox concentrations were varied by {+-}25% to {+-}50% by adding various combinations of a mixture of HC, clean air, or NO{sub x} (perturbed chambers). The O{sub 3} and NO{sub x} concentration in each chamber was monitored throughout the day to determine O{sub 3} (max). The initial HC and NO{sub x} concentration effects were determined by comparing the maximum ozone concentrations measured in the perturbed and unperturbed chambers. Ozone isopleths were constructed from the empirical model obtained of measurements of the eight chambers and plotted in a graph whose axe were the initial HC and NO{sub x} values. For the average initial conditions that were measured in Mexico City, it was found that the most efficient strategy to reduce the maximum concentration of O{sub 3} is the one that reduces NO{sub x}. [Spanish] Se realizaron experimentos de camaras de esmog con el aire de la ciudad de Mexico para determinar las respuestas de los niveles maximos de ozono a los cambios en las concentraciones iniciales de hidrocarburos, HC y oxido de nitrogeno, NO{sub x}. Por lo general, se llenaron 8 bolsas con aire matutino de la Ciudad de Mexico. En algunas camaras, las concentraciones iniciales fueron cambiadas de 25% a 50%, anadiendo varias concentraciones de una mezcla de HC, aire limpio y/o NO{sub x}. La concentracion de O{sub 3} y NO{sub x}, en cada camara, fueron monitoreadas a lo largo del dia para determinar el maximo de O{sub 3}. El efecto de los HC y el NO{sub x} fue determinado por comparacion del maximo de ozono formado en las camaras, que fueron perturbadas por adicion o reduccion de HC y/o Nox

  3. Partial protection of seasonal trivalent inactivated vaccine against novel pandemic influenza A/H1N1 2009: case-control study in Mexico City.

    Science.gov (United States)

    Garcia-Garcia, Lourdes; Valdespino-Gómez, Jose Luis; Lazcano-Ponce, Eduardo; Jimenez-Corona, Aida; Higuera-Iglesias, Anjarath; Cruz-Hervert, Pablo; Cano-Arellano, Bulmaro; Garcia-Anaya, Antonio; Ferreira-Guerrero, Elizabeth; Baez-Saldaña, Renata; Ferreyra-Reyes, Leticia; Ponce-de-León-Rosales, Samuel; Alpuche-Aranda, Celia; Rodriguez-López, Mario Henry; Perez-Padilla, Rogelio; Hernandez-Avila, Mauricio

    2009-10-06

    To evaluate the association of 2008-9 seasonal trivalent inactivated vaccine with cases of influenza A/H1N1 during the epidemic in Mexico. Frequency matched case-control study. Specialty hospital in Mexico City, March to May 2009. 60 patients with laboratory confirmed influenza A/H1N1 and 180 controls with other diseases (not influenza-like illness or pneumonia) living in Mexico City or the State of Mexico and matched for age and socioeconomic status. Odds ratio and effectiveness of trivalent inactivated vaccine against influenza A/H1N1. Cases were more likely than controls to be admitted to hospital, undergo invasive mechanical ventilation, and die. Controls were more likely than cases to have chronic conditions that conferred a higher risk of influenza related complications. In the multivariate model, influenza A/H1N1 was independently associated with trivalent inactivated vaccine (odds ratio 0.27, 95% confidence interval 0.11 to 0.66) and underlying conditions (0.15, 0.08 to 0.30). Vaccine effectiveness was 73% (95% confidence interval 34% to 89%). None of the eight vaccinated cases died. Preliminary evidence suggests some protection from the 2008-9 trivalent inactivated vaccine against pandemic influenza A/H1N1 2009, particularly severe forms of the disease, diagnosed in a specialty hospital during the influenza epidemic in Mexico City.

  4. Identification of influenza A pandemic (H1N1) 2009 variants during the first 2009 influenza outbreak in Mexico City.

    Science.gov (United States)

    Zepeda, Hector M; Perea-Araujo, Lizbeth; Zarate-Segura, Paola B; Vázquez-Pérez, Joel A; Miliar-García, Angel; Garibay-Orijel, Claudio; Domínguez-López, Aarón; Badillo-Corona, Jesús A; López-Orduña, Eduardo; García-González, Octavio P; Villaseñor-Ruíz, Ignacio; Ahued-Ortega, Armando; Aguilar-Faisal, Leopoldo; Bravo, Jorge; Lara-Padilla, Eleazar; García-Cavazos, Ricardo J

    2010-05-01

    In March 2009, public health surveillance detected increased numbers of influenza-like illness presenting to hospitals in Mexico City. The aetiological agent was subsequently determined to be a novel influenza A (H1N1) triple reassortant, which has spread worldwide. As a consequence the World Health Organisation has declared the first Influenza pandemic of the 21st century. To describe clinically and molecularly the first outbreak of influenza A pH1N1 (2009) during 1-5 May to establish a baseline of epidemiological data for pH1N1. Also, to monitor for the emergence of antiviral resistance, and mutations affecting virulence and transmissibility. Samples were collected from 751 patients with influenza-like symptoms throughout Mexico City and were tested for influenza A pH1N1 (2009) using real-time PCR. In the samples that were positive for influenza A pH1N1 (2009) fragments from the haemagglutinin (H1) and neuraminidase (N1) genes were sequenced. A total of 203/751 (27%) patients were positive for the pandemic H1N1 (2009) virus (53% male and 47% female). The 0-12-year-old group was the most affected 85/751 (42%). Sequence analysis showed five new variants of the pandemic H1N1 (2009) virus for NA: G249E (GQ292900), M269I (GQ292892), Y274H (GQ292913), T332A (GQ292933), N344K (GQ292882), and four variants for HA: N461K (GQ293006), K505R (GQ292989), I435V (GQ292995), I527N (GQ292997). We have provided a baseline of epidemiological data from the first outbreak of influenza A pH1N1 (2009) during 1-5 May in Mexico City. The sequencing of partial fragments of the HA and NA genes did not show the presence of previously described mutations affecting known sites of antiviral resistance in seasonal influenza A such as the H275Y (oseltamivir resistance), R293 or N295 etc. Copyright 2010 Elsevier B.V. All rights reserved.

  5. Evaluation of the imputation performance of the program IMPUTE in an admixed sample from Mexico City using several model designs

    Science.gov (United States)

    2012-01-01

    Background We explored the imputation performance of the program IMPUTE in an admixed sample from Mexico City. The following issues were evaluated: (a) the impact of different reference panels (HapMap vs. 1000 Genomes) on imputation; (b) potential differences in imputation performance between single-step vs. two-step (phasing and imputation) approaches; (c) the effect of different INFO score thresholds on imputation performance and (d) imputation performance in common vs. rare markers. Methods The sample from Mexico City comprised 1,310 individuals genotyped with the Affymetrix 5.0 array. We randomly masked 5% of the markers directly genotyped on chromosome 12 (n = 1,046) and compared the imputed genotypes with the microarray genotype calls. Imputation was carried out with the program IMPUTE. The concordance rates between the imputed and observed genotypes were used as a measure of imputation accuracy and the proportion of non-missing genotypes as a measure of imputation efficacy. Results The single-step imputation approach produced slightly higher concordance rates than the two-step strategy (99.1% vs. 98.4% when using the HapMap phase II combined panel), but at the expense of a lower proportion of non-missing genotypes (85.5% vs. 90.1%). The 1,000 Genomes reference sample produced similar concordance rates to the HapMap phase II panel (98.4% for both datasets, using the two-step strategy). However, the 1000 Genomes reference sample increased substantially the proportion of non-missing genotypes (94.7% vs. 90.1%). Rare variants (Mexico City, which has primarily Native American (62%) and European (33%) contributions. Genotype concordances were higher than 98.4% using all the imputation strategies, in spite of the fact that no Native American samples are present in the HapMap and 1000 Genomes reference panels. The best balance of imputation accuracy and efficiency was obtained with the 1,000 Genomes panel. Rare variants were not captured effectively by any of

  6. Evaluation of radiological protection aspects in radiodiagnostic rooms in Mexico City

    International Nuclear Information System (INIS)

    Escobar A, L.; Vizuet G, J.; Ruiz, M.A.

    1996-01-01

    The preliminary results of an evaluation of radiological protection carried out in radiology services of different hospitals of Mexico are shown. The evaluated points were: relative aspects of the room, operation parameters of operation of the equipment, work procedures and training about radiological protection for the equipment operators. (authors). 2 refs., 1 fig

  7. “The rupture generation” : nineteenth-century Nahua intellectuals in Mexico City, 1774-1882

    NARCIS (Netherlands)

    Segovia-Liga, A.

    2017-01-01

    This current dissertation explores several ideas about the construction of the Nahua intellectual tradition in 19th century-Mexico. Initially, the argument of this dissertation focuses on examining the intellectual tradition among Indigenous Peoples in Mesoamerica after the European invasion of the

  8. Recomendaciones de Liderazgo para los Dueños de Pymes Familiares Exportadoras y no Exportadoras en Nuevo Leon

    Directory of Open Access Journals (Sweden)

    Maria Eloisa Treviño Ayala

    2011-07-01

    Full Text Available The main purpose of this document is to state the importance that small and medium-sized enterprises (SMEs exporting and non-exporting have, as well as family businesses in Mexico´s economy and specifically in the state of Nuevo Leon. It establishes certain family SMEs, exporting and non-exporting, characteristics to take into consideration by Nuevo Leon leaders that seek success under the determinant of profits. It also locates qualities, from our stand point, classic and contemporaries, recommended for managers and administrators of this type of companies.

  9. The Effect of Composition, Size, and Solubility on Acute Pulmonary Injury in Rats Following Exposure to Mexico City Ambient Particulate Matter Samples

    Science.gov (United States)

    Particulate matter (PM) associated metals contribute to the adverse cardiopulmonary effects following exposure to air pollution. Here, we investigated how variation in the composition and size of ambient PM collected from two distinct regions in Mexico City relates to toxicity d...

  10. A "Great Roads" Approach to Teaching Modern World History and Latin American Regional Survey Courses: A Veracruz to Mexico City Case Study.

    Science.gov (United States)

    Brown, James Seay, Jr.; Sullivan-Gonzalez, Douglass

    2002-01-01

    Outlines an innovative way of teaching "World History Since 1500" at Samford University (Birmingham, Alabama) called the "great roads" approach, centered upon important roads in a country's history. Presents the "Veracruz to Mexico City corridor" case study used to teach a Latin American modern history course. (CMK)

  11. Observed trends in ground-level O3 in Monterrey, Mexico, during 1993–2014: comparison with Mexico City and Guadalajara

    Directory of Open Access Journals (Sweden)

    I. Y. Hernández Paniagua

    2017-07-01

    Full Text Available Here, we present an assessment of long-term trends in O3 and odd oxygen (O3 + NO2 at the industrial Monterrey metropolitan area (MMA in NE Mexico. Diurnal amplitudes in Ox (AVd are used as a proxy for net O3 production, which is influenced by the NO2 photolysis rate. No significant differences in the AVd are observed between weekends and weekdays, although the largest AVd values are observed at sites downwind of industrial areas. The highest O3 mixing ratios are observed in spring, with minimum values in winter. The largest annual variations in O3 are typically observed downwind of the MMA, with the lowest variations generally recorded in highly populated areas and close to industrial areas. A wind sector analysis of mixing ratios of O3 precursors revealed that the dominant sources of emissions are located in the industrial regions within the MMA and surrounding area. Significant increasing trends in O3 in spring, summer, and autumn are observed depending on site location, with trends in annual averages ranging between 0.19 and 0.33 ppb yr−1. Overall, from 1993 to 2014, within the MMA, O3 has increased at an average rate of 0.22 ppb yr−1 (p < 0. 01, which is in marked contrast with the decline of 1.15 ppb yr−1 (p < 0. 001 observed in the Mexico City metropolitan area (MCMA for the same period. No clear trend is observed from 1996 to 2014 within the Guadalajara metropolitan area (GMA.

  12. The use of the electric vehicle in the metropolitan area of Mexico city; Uso de vehiculos electricos en el area metropolitana de la ciudad de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Robles, G. [Centro de Intrumentos, UNAM, Mexico, D. F. (Mexico); Sheinbaum, C. [Instituto de Ingenieria, UNAM, Mexico, D. F. (Mexico)

    1997-12-31

    A study is performed on the impact that the introduction of the electric vehicle (EV) would have in the environmental pollution of the metropolitan area of Mexico City (MAMC) for different penetration scenarios of this technology and the costs of the electric vehicle is analyzed and compared with its counterpart, the gasoline vehicle. The associated emissions of a fleet formed of EV and internal combustion engine vehicles (ICEV) were determined and the emissions reduction of the contaminants considered in the period 1995-2010 produced was analyzed. It was found that the introduction of EV could importantly reduce the carbon monoxide, methane and carbon dioxide and marginally the nitrogen oxides. It was determined that if the EV is massively produced its total cost for its entire useful life would be comparable to the cost of the ICEV. [Espanol] Se realiza un estudio sobre el impacto que tendria la introduccion de vehiculos electricos (VE) en la contaminacion ambiental del area metropolitana de la ciudad de Mexico (AMCM) para diferentes escenarios de penetracion de esta tecnologia y se analiza el costo de los vehiculos electricos en comparacion con su contraparte de gasolina. Se determinaron las emisiones asociadas a una flota compuesta de VE y vehiculos con motor de combustion interna (VMCI) y se analizo la reduccion que producia en las emisiones de los diferentes contaminantes considerados en el periodo 1995-2010. Se encontro que la introduccion de VE podria reducir de manera importante las emisiones de monoxido de carbono, metano y dioxido de carbono y marginalmente las de oxido de nitrogeno. Se determino que si los VE son producidos masivamente su costo total para toda su vida util seria comparable al correspondiente al de los VMCI.

  13. Protocol for a prospective longitudinal study of risk factors for hypertension incidence in a Mexico City population: the Tlalpan 2020 cohort.

    Science.gov (United States)

    Colín-Ramírez, Eloisa; Rivera-Mancía, Susana; Infante-Vázquez, Oscar; Cartas-Rosado, Raúl; Vargas-Barrón, Jesús; Madero, Magdalena; Vallejo, Maite

    2017-07-31

    Systemic hypertension (HTN) is a common risk factor for cardiovascular disease. In Mexico, HTN prevalence has increased over time and is currently 31%. Nonetheless, information about the country's HTN incidence and its associated risk factors is scarce. Understanding this condition is a priority for identifying the scope of primary prevention. The main objective of this study is to evaluate the effect of traditional and non-traditional risk factors on the incidence of HTN in a cohort of healthy Mexico City residents under biannual follow-up for 10 years. A prospective longitudinal study is proposed in which clinically healthy residents of Mexico City between 20 and 50 years old will be recruited; the participants will be evaluated every 2 years over a period of 10 years or until they develop HTN. Evaluations regarding sociodemographic, clinical, anthropometric, biochemical, diet, physical activity, stress, sleep quality, alcohol and tobacco consumption factors will be performed. The participants will be recruited from the 16 municipalities of Mexico City through promotional strategies aimed at the community and will be clinically evaluated at a tertiary care institution, Instituto Nacional de Cardiología Ignacio Chávez (National Institute of Cardiology Ignacio Chavez), located in Mexico City, Mexico. Sample size estimated for this study is 3436, and the Cox proportional hazards model will be used to estimate HRs for the association between explanatory variables and HTN using both raw and adjusted data. This study was approved by the Institutional Bioethics Committee of the Instituto Nacional de Cardiología Ignacio Chávez (National Institute of Cardiology Ignacio Chavez) under number 13-802. Findings from this study will be disseminated through scientific papers and research conferences. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise

  14. Developing a Hierarchical Model for the Spatial Analysis of PM10 Pollution Extremes in the Mexico City Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Alejandro Ivan Aguirre-Salado

    2017-07-01

    Full Text Available We implemented a spatial model for analysing PM 10 maxima across the Mexico City metropolitan area during the period 1995–2016. We assumed that these maxima follow a non-identical generalized extreme value (GEV distribution and modeled the trend by introducing multivariate smoothing spline functions into the probability GEV distribution. A flexible, three-stage hierarchical Bayesian approach was developed to analyse the distribution of the PM 10 maxima in space and time. We evaluated the statistical model’s performance by using a simulation study. The results showed strong evidence of a positive correlation between the PM 10 maxima and the longitude and latitude. The relationship between time and the PM 10 maxima was negative, indicating a decreasing trend over time. Finally, a high risk of PM 10 maxima presenting levels above 1000 μ g/m 3 (return period: 25 yr was observed in the northwestern region of the study area.

  15. Occult cancer in patients with deep-vein thrombosis in a general hospital at Mexico City: A pilot study

    Directory of Open Access Journals (Sweden)

    Christian O Ramirez-Serrano Torres

    2017-01-01

    Full Text Available Background: We aimed to explore the frequency of occult cancer in patients with deep-vein thrombosis (DVT at a general hospital in Mexico City. Materials and Methods: From March 2012 to February 2015, all patients with primary DVT of lower extremities attended in the emergency department of our hospital were studied. Initially, all patients were evaluated with clinical history, physical examination, basic laboratories, abdominal ultrasound, chest X-ray, and duplex venous ultrasonography. In a case-by-case approach, if necessary, computed tomography, endoscopy, colonoscopy, and tumor markers were done. Results: From 182 patients with primary DVT, 30 (16.5% presented occult cancer: Thirteen males and 17 females, with an average age of 61 years. In males, prostate cancer prevailed (6/13, 46%; meanwhile, in females, pelvic gynecologic cancers predominated (7/17, 41%. Conclusion: Our results suggest that in Mexican patients with primary DVT, occult cancer is frequent.

  16. Detection of Clostridium perfringens in yearling lamb meat (barbacoa), head, and gut tacos from public markets in Mexico City.

    Science.gov (United States)

    Natividad-Bonifacio, Iván; Vázquez-Quiñones, Carlos R; Rodas-Suárez, Oscar R; Fernández, Francisco J; Rodríguez-Solis, Esteban; Quiñones-Ramírez, Elsa Irma; Vázquez-Salinas, Carlos

    2010-06-01

    No reports on the incidence of Clostridium perfringens in popularly-consumed food from Mexico City have been published; neither are there any reports that have analyzed food consumed in popular markets and less established restaurants. Therefore, this study is aimed at providing data to evaluate the relevance of C. perfringens as an etiologic agent of food-borne diseases. Of the 650 analyzed samples, 106 (16.3%) were positive for C. perfringens; 6.4% (16/250) isolates were from barbacoa, 19% (38/200) from head, and 13% (52/200) from gut tacos. The presence of C. perfringens in these popular-consumed foods demonstrates its relevance as an etiologic agent of food-borne diseases, and confirms the great sanitary risk involved in their consumption. These results may serve as a basis for the Mexican sanitary authorities to control the microbiological quality of street-made foods.

  17. Occult cancer in patients with deep-vein thrombosis in a general hospital at Mexico City: A pilot study.

    Science.gov (United States)

    Ramírez-Serrano Torres, Christian O; Román-Guzmán, Edgardo; Ortiz-Mendoza, Carlos-Manuel

    2017-01-01

    We aimed to explore the frequency of occult cancer in patients with deep-vein thrombosis (DVT) at a general hospital in Mexico City. From March 2012 to February 2015, all patients with primary DVT of lower extremities attended in the emergency department of our hospital were studied. Initially, all patients were evaluated with clinical history, physical examination, basic laboratories, abdominal ultrasound, chest X-ray, and duplex venous ultrasonography. In a case-by-case approach, if necessary, computed tomography, endoscopy, colonoscopy, and tumor markers were done. From 182 patients with primary DVT, 30 (16.5%) presented occult cancer: Thirteen males and 17 females, with an average age of 61 years. In males, prostate cancer prevailed (6/13, 46%); meanwhile, in females, pelvic gynecologic cancers predominated (7/17, 41%). Our results suggest that in Mexican patients with primary DVT, occult cancer is frequent.

  18. Healthcare and Social Services Providers Who Serve Sexual and Gender Minorities in a U.S.-Mexico Border City.

    Science.gov (United States)

    Loza, Oralia; Alvarez, Carlos R; Peralta-Torres, David

    2018-01-15

    Sexual and gender minorities, including lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals, experience barriers to healthcare as a result of stigma, discrimination, and poor cultural competence by healthcare and social services providers (HCSSP). The purpose of the study is to increase access to care and services for the LGBTQ community in a U.S.-Mexico border city by identifying LGBTQ-friendly HCSSP. A survey, developed based on concerns voiced in a predominantly Hispanic LGBTQ community, was administered to HCSSP and used to create a referral list, "The Purple Pages of El Paso" (PPoEP). Overall, 77 HCSSP have responded and 43 are included in the most recent version of the PPoEP. This model for developing a referral list of providers can be adapted in areas where LGBTQ communities face similar barriers to care and services. To be effective in reducing barriers to care, PPoEP must be updatable and sustainable.

  19. Emissions of black carbon and co-pollutants emitted from diesel vehicles in the Mexico City Metropolitan Area

    Science.gov (United States)

    Zavala, Miguel; Molina, Luisa T.; Fortner, Edward; Knighton, Berk; Herndon, Scott; Yacovitch, Tara; Floerchinger, Cody; Roscioli, Joseph; Kolb, Charles; Mejia, Jose Antonio; Sarmiento, Jorge; Paramo, Victor Hugo; Zirath, Sergio; Jazcilevich, Aron

    2014-05-01

    Black carbon emitted from freight, public transport, and heavy duty trucks sources is linked with adverse effects on human health. In addition, the control of emissions of black carbon, an important short-lived climate forcing agent (SLCF), has recently been considered as one of the key strategies for mitigating regional near-term climate change. Despite the availability of new emissions control technologies for reducing emissions from diesel-powered mobile sources, their introduction is still not widespread in many urban areas and there is a need to characterize real-world emission rates of black carbon from this key source. The emissions of black carbon, organic carbon, and other gaseous and particle pollutants from diesel-powered mobile sources in Mexico were characterized by deploying a mobile laboratory equipped with real-time instrumentation in Mexico City as part of the SLCFs-Mexico 2013 project. From February 25-28 of 2013 the emissions from selected diesel-powered vehicles were measured in both controlled experiments and real-world on-road driving conditions. Sampled vehicles had several emissions levels technologies, including: EPA98, EPA03, EPA04, EURO3-5, and Hybrid. All vehicles were sampled using diesel fuel and several vehicles were measured using both diesel and biodiesel fuels. Additional measurements included the use of a remote sensing unit for the co-sampling of all tested vehicles, and the installation and operation of a Portable Emissions Measurements System (PEMS) for the measurement of emissions from a test vehicle. We will present inter-comparisons of the emission factors obtained among the various vehicle technologies that were sampled during the experiment as well as the inter-comparison of results from the various sampling platforms. The results can be used to

  20. Abortion, contraceptive use, and adolescent pregnancy among first-year medical students at a major public university in Mexico City.

    Science.gov (United States)

    Ortiz-Ortega, Adriana; De La Torre, Guadalupe García; Galván, Fernando; Cravioto, Patricia; Paz, Francisco; Díaz-Olavarrieta, Claudia; Ellertson, Charlotte; Cravioto, Alejandro

    2003-08-01

    If properly trained, medical students could become future opinion leaders in health policy and could help the public to understand the consequences of unwanted pregnancies and of abortions. The objective of this study was to analyze the frequency of unwanted pregnancies and induced abortions that had occurred among women who were first-year medical students at a major public university in Mexico City and to compare the experiences of those women with the experiences of the general population of Mexican females aged 15 to 24. In 1998 we administered a cross-sectional survey to all the first-year medical students at the National Autonomous University of Mexico, which is the largest university in Latin America. For this study we analyzed 549 surveys completed by female students. Out of the 549 women, 120 of them (22%) had been sexually active at some point. Among those 120 sexually active students, 100 of them (83%) had used a contraceptive method at some time, and 19 of the 120 (16%) had been pregnant. Of those 19 women who had been pregnant, 10 of them had had an illegal induced abortion (in Mexico, abortions are illegal except under a small number of extenuating circumstances). The reported abortion rate among the female medical students, 2%, was very low in comparison with the 11% rate for women of similar ages in the Mexican general population. The lower incidence of abortion among the female medical students indicates that when young Mexican women have access to medical information and are highly motivated to avoid unintended pregnancy and abortion, they can do so.

  1. Frequency and risk factors associated with dry eye in patients attending a tertiary care ophthalmology center in Mexico City.

    Science.gov (United States)

    Martinez, Jaime D; Galor, Anat; Ramos-Betancourt, Nallely; Lisker-Cervantes, Andrés; Beltrán, Francisco; Ozorno-Zárate, Jorge; Sánchez-Huerta, Valeria; Torres-Vera, Marco-Antonio; Hernández-Quintela, Everardo

    2016-01-01

    The purpose of this study was to ascertain the frequency and risk factors of dry eye (DE) among patients attending a tertiary care ophthalmology center in Mexico. Approximately 338 consecutive new patients attending a tertiary care ophthalmology center in Mexico City underwent an ocular surface examination, which included tear film break-up time, fluorescein corneal staining, Schirmer's test, and evaluation of meibum quality. Symptoms of DE were evaluated by the Ocular Surface Disease Index and Dry Eye Questionnaire-5. Information on demographics, exposures, past medical and ocular history, and medications was also collected. The frequency of severe DE symptoms was found to be 43% based on the Ocular Surface Disease Index and 30% based on Dry Eye Questionnaire-5. Risk factors significantly associated with increased DE symptoms included dry mouth and gastrointestinal ulcer medications. With regard to signs, aqueous tear deficiency was a less-frequent finding (22%) in our population than evaporative deficiency (94%). Risk factors associated with aqueous tear deficiency were dry mouth and diuretic use. No risk factors were associated with evaporative deficiency. Risk factors associated with meibomian gland dysfunction included old age, male sex, arthritis, and use of an antihypertensive. The only risk factor associated with corneal staining was dry mouth. This is the first study to demonstrate the frequency of symptomatic and clinical DE in a tertiary care ophthalmology center in Mexico. The frequency of DE ranged from 30% using a symptomatic definition to 94% using objective measures. Different risk factors were found for different aspects of DE, suggesting differing underlying pathophysiologies behind different DE subtypes.

  2. Miscarriage history and Toxoplasma gondii infection: A cross-sectional study in women in Durango City, Mexico.

    Science.gov (United States)

    Alvarado-Esquivel, C; Pacheco-Vega, S J; Hernández-Tinoco, J; Centeno-Tinoco, M M; Beristain-García, I; Sánchez-Anguiano, L F; Liesenfeld, O; Rábago-Sánchez, E; Berumen-Segovia, L O

    2014-06-01

    Through a cross-sectional study design, 326 women with a history of miscarriage were examined for anti-Toxoplasma gondii IgG and IgM antibodies in Durango City, Mexico. Prevalence association with sociodemographic, clinical, and behavioral characteristics in women with miscarriage was also investigated. Twenty-two (6.7%) of the 326 women studied had anti-T. gondii IgG antibodies and two (0.6%) were also positive for anti-T. gondii IgM antibodies. Seroprevalence of T. gondii infection was not influenced by age, birth place, occupation, educational level, or socioeconomic status. In contrast, logistic regression showed that T. gondii exposure was associated with consumption of raw or undercooked meat (OR = 6.84; 95% CI: 1.04-44.95; P = 0.04) and consumption of chicken brains (OR = 18.48; 95% CI: 1.26-269.43; P = 0.03). This is the first study on the seroepidemiology of T. gondii infection in women with a history of miscarriage in Northern Mexico. Of interest, we also observed an association of T. gondii exposure with consumption of chicken brains. Contributing factors for T. gondii exposure found in the present study should be taken into consideration for public health measures to avoid infection with T. gondii and its sequelae.

  3. Correlates of early versus later initiation into sex work in two Mexico-U.S. border cities.

    Science.gov (United States)

    Loza, Oralia; Strathdee, Steffanie A; Lozada, Remedios; Staines, Hugo; Ojeda, Victoria D; Martínez, Gustavo A; Amaro, Hortensia; Patterson, Thomas L

    2010-01-01

    To examine correlates of early initiation into sex work in two Mexico-U.S. border cities. Female sex workers (FSWs) >/=18 years without known HIV infection living in Tijuana and Ciudad Juarez who had recent unprotected sex with clients underwent baseline interviews. Correlates of initiation into sex work before age 18 were identified with logistic regression. Of 920 FSWs interviewed in Tijuana (N=474) and Ciudad Juarez (N=446), 9.8% (N=90) were early initiators (abuse as a child (42.2% vs. 18.7%, pchild abuse (adjOR=2.92). Factors associated with later initiation included less education (adjOR=0.43 per 5-year increase), migration (adjOR=0.47), and initiating sex work for better pay (adjOR=0.44) or to support children (adjOR=0.03). Different pathways for entering sex work are apparent among younger versus older females in the Mexico-U.S. border region. Among girls, interventions are needed to prevent inhalant use and child abuse and to offer coping skills; among older initiators, income-generating strategies, childcare, and services for migrants may help to delay or prevent entry into sex work. Copyright 2010 Society for Adolescent Medicine. Published by Elsevier Inc. All rights reserved.

  4. Public policy performance for social development: solar energy approach to assess technological outcome in Mexico City Metropolitan Area.

    Science.gov (United States)

    Arenas-Aquino, Angel Raúl; Matsumoto-Kuwabara,