Higher heavy metal contamination indoors than outdoors during COVID-19 in Mexico City.

People spend most of their time indoors, especially during the coronavirus disease. Prolonged exposure to heavy metal-contaminated dust can be harmful to human health. The objectives of this study were to identify the contamination level in outdoor and indoor dust, compare contamination in both environments, and assess the human health risk. Two-hundred thirty-nine samples of dust were taken by Mexico City citizens in 38 homes on the weekends of May 2020. Heavy metal concentrations were measured through XRF. The contamination level was set using the contamination factor with a local and global background value, mixed linear models were used to identify indoor and outdoor differences, and USEPA human health risk methodology was used. Pb, Zn, and Cu had the highest contamination levels, followed by Sr and Mn, using both the local and global background values. The Pb, Zn, and Cu contamination was greater indoors, while higher Mn, Sr, and Fe were detected outdoors. According to the outdoor/indoor ratios, the main sources of Ca, Pb, Zn, and Cu must be indoors, while the main sources of Fe, Mn, Sr, Y, and Ti are outdoors. A human health risk was not detected, as the hazard index was lower than one. However, ailments can be developed due to exposure to Pb, Mn, and Fe in children (hazard index > 0.1). A higher risk due to Pb exposition was found indoors. Indoor environments in Mexico City were more contaminated by heavy metals and represented a higher risk to human health than outdoors during the pandemic isolation.

Convolutional Neural Networks to Assist the Assessment of Lattice Parameters from X-ray Powder Diffraction.

This article presents the development of convolutional neural networks (CNNs) for the estimation of lattice parameters in organic compounds across various crystal systems. A comprehensive collection of 92,085 organic compounds was utilized to train the CNNs, encompassing crystals with unit cells containing up to 512 atoms and a maximum unit cell volume of 8000 Å3. Simulated diffraction patterns were generated for each compound, comprising four diffraction patterns with different crystal sizes. These diffraction patterns were generated within a 2θ window of 3-60°, employing a step size of 0.02051°. Two distinct CNN architectures were developed with differing input data. The first CNN, referred to as XRD-CNN, was trained solely on diffraction patterns. In the test set, XRD-CNN demonstrated a mean absolute percentage error (MAPE) of 11.04% for unit cell vectors, 7.40% for angles, and 26.83% for unit cell volume. The second CNN, XRDElem-CNN, incorporated a binary representation of atoms within the unit cell as an additional input. XRDElem-CNN achieved improved performance, yielding MAPE values of 4.73% for unit vectors, 6.49% for angles, and 6.05% for the unit cell volume. To validate the performance of XRDElem-CNN, real diffraction patterns obtained from a conventional laboratory diffractometer (Cu Kα wavelength) were employed. Various representations of atoms within the unit cell were proposed, which were computationally efficient for evaluation with the CNNs. The assessed lattice parameters by XRDElem-CNN were validated using the Lp-search method, showing agreement with the reported values.

Evidence of a Thermal Diffusivity Gap in Sintered Li-Co-Sb-O Solid Solutions.

In this work, the thermal properties of ternary Li3x Co7-4x Sb2+x O12 solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li+ and Sb5+, accompanied by the reduction of Co2+, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.

Validation and application of the Insulin Treatment Appraisal Scale in Cuban patients with type 2 diabetes mellitus.

INTRODUCTION: The purpose of this study was to validate the Insulin Treatment Appraisal Scale (ITAS) in the Cuban population with type 2 diabetes mellitus. MATERIAL AND METHODS: A cross-sectional, multicentre analytical study was performed in Cuba from February 2020 to April 2021; 199 patients were surveyed in a hospital institution and in primary healthcare. We used the Insulin Treatment Appraisal Scale, consisting of 20 items, with a minimum score of 20 points and a maximum of 100, where the higher the score, the worse the perception of insulin therapy. The validity of the instrument was determined by means of an exploratory factor analysis. The internal consistency and reliability of the scale were calculated by means of Cronbach's alpha coefficient. A K-means cluster analysis was performed to establish a cut-off point for poor perception of insulin therapy. RESULTS: The exploratory factor analysis supported the validity of the instrument, with a Cronbach's alpha of 0.747. There were statistically significant differences between patients under insulin and non-insulin treatment in terms of the answers given in all items of the scale. The total mean score obtained was 51.96 ±â€¯10.78, and it was lower in insulin users compared to those who used other drugs (49.79 ±â€¯10.07 vs 55.09 ±â€¯11.12). A score ≥65 was proposed as a cut-off point for poor perception of insulin therapy. A positive relationship was found between the body mass index values and the total score of the scale. Being female and current treatment not involving insulin were factors associated with low perception of insulin therapy. CONCLUSIONS: The instrument proved to be valid for the population in which it was applied. Insulin users turned out to be the ones with the best perception about its use. A cut-off point of ≥65 points for poor perception of insulin treatment was proposed for evaluation and comparison in future studies in other patient populations.

COVID-19 contagion concern scale (PRE-COVID-19): Validation in Cuban patients with type 2 diabetes.

AIMS: It is important to have valid and reliable measures to determine the psychological impact of COVID-19 in patients with diabetes; however, few instruments have been developed and validated for this population. Therefore, the aim of this study was to validate the Scale of Worry for Contagion of COVID-19 (PRE-COVID-19) in a sample of patients with diabetes mellitus (DM). MATERIALS AND METHODS: A total of 219 patients (66.2% female, mean age 58.5 SD = 18.2) participated, selected through non-probabilistic sampling. The PRE-COVID-19 and the Generalized Anxiety Disorder Scale-2 were applied. Reliability analysis was performed for internal consistency, structural equation modeling and item response theory modeling. RESULTS: The results show that a unidimensional 5-item model presents satisfactory goodness-of-fit indices and excellent reliability values. Likewise, convergent validity between the PRE-COVID-19 and a measure of anxiety is evident. All items present adequate discrimination parameters, allowing for discerning between those patients with critical concern about COVID-19 contagion from those with severe concern. CONCLUSION: It is concluded that the PRE-COVID-19 is an instrument with adequate psychometric properties to measure concern about COVID-19 infection and the emotional impact in patients with DM.

An Insight to the Composition of Pre-Hispanic Mayan Funerary Pigments by 1H-NMR Analysis.

The funerary rites of particular members of the pre-Hispanic Mayan society included the pigmentation of the corpse with a red color. In order to understand this ritual, it is first necessary to identify the constituents of the pigment mixture and then, based on its properties, analyze the possible form and moment of application. In the present approach, 1H-NMR analysis was carried to detect organic components in the funerary pigments of Xcambó, a small Maya settlement in the Yucatan Peninsula. The comparison of the spectra belonging to the pigment found in the bone remains of seven individuals, and those from natural materials, led to the identification of beeswax and an abietane resin as constituents of the pigment, thus conferring it agglutinant and aromatic properties, respectively. The 1H-NMR analysis also allowed to rule out the presence of copal, a resin found in the pigment cover from paramount chiefs from the Mayan society. Additionally, a protocol for the extraction of the organic fraction from the bone segment without visible signs of analysis was developed, thus broadening the techniques available to investigate these valuable samples.

Effect of salinity on zinc toxicity (ZnCl2 and ZnO nanomaterials) in the mosquitofish (Gambusia sexradiata).

Zn is an essential trace metal in living beings. However, excessive concentrations can cause toxic effects even in the aquatic biota. Zn is widely used in different industrial sectors, which has increased its presence in aquatic environments. To assess the acute toxicity of Zn, bioassays were performed with the fish Gambusia sexradiata for a 96-h exposure using ZnCl2 (0 and 15 salinity) and ZnO nanomaterials (0 salinity). The mean lethal concentrations (LC50-96 h) for ZnCl2 were 25.36 (19.64-32.76) and 177.91 (129.39-244.63) mg Zn L-1 to 0 and 15 salinity, respectively. The increased concentration of ZnCl2 showed a dose-response relationship; similarly, the increase in salinity significantly reduces the toxicity of Zn. Characterisation of ZnO nanomaterials was carried out by FTIR, DRX, SEM, DLS and zeta potential. The FTIR spectra showed the characteristic band of Zn-O vibration at 364 cm-1, while DRX presents the hexagonal wurtzite structure with an average crystallite size of 40 nm. SEM micrographs reveal rod-like shapes with lengths and diameters of 40-350 nm and 90 nm, respectively. Agglomerates of 423 nm in water suspension were obtained by DLS and zeta potential of + 14.4 mV. Under these conditions, no mortality was observed due to the rapid flocculation/precipitation of ZnO nanomaterials, which involved brief interaction periods of Zn in the water column with the fish. Gambusia sexradiata is affected by increased Zn concentrations in hard water conditions, and salinity changes modified Zn toxicity, placing it as a suitable model for toxicity tests for this type of particles.

Photocatalytic activity of graphene oxide-TiO2 thin films sensitized by natural dyes extracted from Bactris guineensis.

This study synthesized and characterized composites of graphene oxide and TiO2 (GO-TiO2). GO-TiO2 thin films were deposited using the doctor blade technique. Subsequently, the thin films were sensitized with a natural dye extracted from a Colombian source (Bactris guineensis). Thermogravimetric analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance measurements were used for physico-chemical characterization. All the samples were polycrystalline in nature, and the diffraction signals corresponded to the TiO2 anatase crystalline phase. Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) verified the synthesis of composite thin films, and the SEM analysis confirmed the TiO2 films morphological modification after the process of GO incorporation and sensitization. XPS results suggested a possibility of appearance of titanium (III) through the formation of oxygen vacancies (Ov). Furthermore, the optical results indicated that the presence of the natural sensitizer and GO improved the optical properties of TiO2 in the visible range. Finally, the photocatalytic degradation of methylene blue was studied under visible irradiation in aqueous solution, and pseudo-first-order model was used to obtain kinetic information about photocatalytic degradation. These results indicated that the presence of GO has an important synergistic effect in conjunction with the natural sensitizer, reaching a photocatalytic yield of 33%.

Interactions between abundant fungal species influence the fungal community assemblage on limestone.

The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between 11 species of fungi in oligotrophic and copiotrophic media and on limestone coupons. In a previous study, these species were the most frequently isolated in the epilithic biofilms of limestone walls exposed to a subtropical climate. In the culture media, we found a greater frequency of intra- and interspecific inhibitory effects in the oligotrophic medium than in the copiotrophic medium. On the limestone coupons, all fungi were able to establish; however, the colonization success rate varied significantly. Cladosporium cladosporioides had a less extensive colonization in isolation (control) than in dual interactions (coexistence) with other species. Phoma eupyrena exhibited the highest colonization success rate and competitive dominance among all tested species. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses revealed that Pestalotiopsis maculans and Paraconiothyrium sp. produced calcium oxalate crystals during their growth on coupon surfaces, both in isolation and in dual interactions. Our results demonstrate that interactions between abundant fungal species influence the fungal colonization on substrates, the biomineralization and the fungal community assemblage growing in limestone biofilms.

Association between overweight and consumption of ultra-processed food and sugar-sweetened beverages among vegetarians / Associação entre o excesso de peso e o consumo de alimentos ultraprocessados e bebidas açucaradas por diferentes grupos vegetarianos

ABSTRACT Objective: To assess the consumption of ultra-processed food and sugar-sweetened beverages and to identify the association of this consumption with overweight among vegetarians. Methods: A cross-sectional study with a convenience sampling method was conducted. Data were collected using an online questionnaire from 8/24/2015 to 10/8/2015. Subjects were male and female vegetarians aged >16 years. Using a food frequency questionnaire, we assessed the weekly consumption of ultra-processed food and sugar-sweetened beverages and described the frequency of daily consumption overall and according to type of vegetarianism. The association between overweight and excessive daily intake of ultra-processed food was analyzed by multiple logistic regression (OR [95CI%]). Results: Information was retrieved from 503 individuals (29.8±8.5 years old); 83.7% were women. The most frequent types of vegetarianism in our sample were ovo-lacto (45.5%) and vegan (41.7%), and the median time of vegetarianism was 5.3 years. The consumption of sugar-sweetened beverages (≥2x/day) and ultra-processed food (≥3x/day) was 21.0% and 16.0%, respectively, and regarding the different vegetarianism types, vegans showed the lowest frequency of excessive daily sugar-sweetened beverages and ultra-processed food consumption. In the multivariable analysis, consumption of ultra-processed food ≥3x/day (2.33 [1.36-4.03]), male sex (1.73 [1.01-2.96]), age ≥35 years (2.03 [1.23-3.36]) and not preparing one's food (1.67 [0.95-2.94]) were independently associated with overweight. Conclusion: Although vegetarianism is frequently associated with a healthier diet and, consequently, prevention of poor health outcomes, this study found that the excessive consumption of sugar-sweetened beverages and ultra-processed food was associated with overweight.

RESUMO Objetivo: Avaliar o consumo de alimentos ultraprocessados e de bebidas açucaradas entre indivíduos vegetarianos e identificar sua associação com o excesso de peso. Métodos: Estudo transversal com método amostral por conveniência, sendo os dados coletados por meio de questionário virtual entre 24/8/2015 e 8/10/2015. A amostra foi composta por indivíduos vegetarianos de ambos os sexos com idade >16 anos. Estudou-se a frequência de consumo de alimentos ultraprocessados e bebidas açucaradas, avaliados por meio de questionário de frequência alimentar, sendo categorizados em função do consumo semanal e diário e do tipo de prática vegetariana. A associação entre excesso de peso e consumo excessivo de alimentos ultraprocessados foi realizada por meio de regressão logística múltipla (RC [IC95%]). Resultados: Participaram desta pesquisa 503 indivíduos (29,8±8,5 anos), com predominância do sexo feminino (83,7%). As principais práticas vegetarianas observadas foram a ovolactovegetariana (45,5%) e a vegana (41,7%), sendo a mediana de tempo de adesão ao vegetarianismo de 5,3 anos. Observou-se que o consumo de bebidas açucaradas (≥2x/dia) e alimentos ultraprocessados (≥3x/dia) foi, respectivamente, 21,0% e 16,0%; em relação aos outros grupos, os veganos apresentaram consumo inferior de alimentos ultraprocessados e bebidas açucaradas. No modelo múltiplo, identificou-se que consumo ≥3x/dia de alimentos ultraprocessados (2,33 [1,36-4,03]), sexo masculino (1,73 [1,01-2,96]), idade ≥35 anos (2,03 [1,23-3,36]) e não preparar as refeições em casa (1,67 [0,95-2,94]) se associaram independentemente com excesso de peso. Conclusão: Embora o vegetarianismo seja frequentemente associado à alimentação saudável e, consequentemente, à pre-venção de desfechos desfavoráveis a saúde, este estudo identificou frequência elevada do consumo diário excessivo de bebidas açucaradas e alimentos ultraprocessados e que este padrão de consumo se associou ao excesso de peso.

Bioweathering Potential of Cultivable Fungi Associated with Semi-Arid Surface Microhabitats of Mayan Buildings.

Soil and rock surfaces support microbial communities involved in mineral weathering processes. Using selective isolation, fungi were obtained from limestone surfaces of Mayan monuments in the semi-arid climate at Yucatan, Mexico. A total of 101 isolates representing 53 different taxa were studied. Common fungi such as Fusarium, Pestalotiopsis, Trichoderma, and Penicillium were associated with surfaces and were, probably derived from airborne spores. In contrast, unusual fungi such as Rosellinia, Annulohypoxylon, and Xylaria were predominantly identified from mycelium particles of biofilm biomass. Simulating oligotrophic conditions, agar amended with CaCO3 was inoculated with fungi to test for carbonate activity. A substantial proportion of fungi, in particular those isolated from mycelium (59%), were capable of solubilizing calcium by means of organic acid release, notably oxalic acid as evidenced by ion chromatography. Contrary to our hypothesis, nutrient level was not a variable influencing the CaCO3 solubilization ability among isolates. Particularly active fungi (Annulohypoxylon stygium, Penicillium oxalicum, and Rosellinia sp.) were selected as models for bioweathering experiments with limestone-containing mesocosms to identify if other mineral phases, in addition to oxalates, were linked to bioweathering processes. Fungal biofilms were seen heavily covering the stone surface, while a biomineralized front was also observed at the stone-biofilm interface, where network of hyphae and mycogenic crystals was observed. X-ray diffraction analysis (XRD) identified calcite as the main phase, along with whewellite and wedellite. In addition, lower levels of citrate were detected by Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Overall, our results suggest that a diverse fungal community is associated with limestone surfaces insemi-arid climates. A subset of this community is geochemically active, excreting organic acids under quasi-oligotrophic conditions, suggesting that the high metabolic cost of exuding organic acids beneficial under nutrient limitation. Oxalic acid release may deteriorate or stabilize limestone surfaces, depending on microclimatic dynamics.

Las redes de los afectos: aprendizajes en la Red de Rehabilitación Basada en Comunidad de las Américas / Networks from the affections: Experienced Learning in the CBR Americas Network

Antecedentes. Las redes son escenarios de concertación y articulación, de afectos, de amores y desamores entre los actores que hacen parte de ellas. Los actores están mediados por intereses acordes con sus contextos y vivencias. Objetivo. Presentar los aprendizajes vividos durante el proceso de liderazgo de la Red de Rehabilitación Basada en Comunidad (RBC) de las Américas a partir de los postulados de José Bernardo Toro. Desarrollo del tema. Se identifican tres momentos de la experiencia vivida: primer momento, armando la red; segundo momento, viviendo la red y tercer momento, recuperando aprendizajes. El artículo incluye un panorama general de la estructuración de las redes de RBC en el mundo y una descripción de las redes que se consolidan alrededor de la discapacidad en las Américas, ello con el propósito de reflexionar sobre el trabajo en red y en equipo. Conclusiones. Los aprendizajes vividos durante los tres últimos años se relacionan con aprender a no agredir al congénere, a comunicarse, a interactuar, a decidir en grupo y a valorar el saber social. Finalmente, damos algunas recomendaciones sobre el camino a seguir.

Background. Networks are scenarios for coordination and joint, affections, love and hate among actors who are part of them. The actors are mediated by interests according to their contexts and experiences. Objective. To show the learning experienced during the process of leading the network of Community Based Rehabilitation (CBR) in the Americas based on the principles of José Bernardo Toro. Development of the subject. Three stages in our experience were identified. First, setting up the network; second, living the network, and third, recovering the learning derived from it. The article includes an overview of the structure of RBC networks in the world and a description of the networks that are consolidated around disability in the Americas. This with purpose of reflectinf on both network work and teamwork. Conclusions. The learning experienced, in the last three years, is related to learning not to attack the congener, communicating, interacting, and deciding as a group and to value social knowledge. Finally, some recommendations on the way forward are provided.

Antifungal coatings based on Ca(OH)2 mixed with ZnO/TiO2 nanomaterials for protection of limestone monuments.

The presence and deteriorating action of microbial biofilms on historic stone buildings have received considerable attention in the past few years. Among microorganisms, fungi are one of the most damaging groups. In the present work, antimicrobial surfaces were prepared using suspensions of Ca(OH)2 particles, mixed with ZnO or TiO2 nanoparticles. The antimicrobial surfaces were evaluated for their antifungal activity both in the dark and under simulated natural photoperiod cycles, using Penicillium oxalicum and Aspergillus niger as model organisms, and two limestone lithotypes commonly used in construction and as materials for the restoration of historic buildings. Both Ca(OH)2-ZnO and Ca(OH)2-TiO2 materials displayed antifungal activity: ZnO-based systems had the best antifungal properties, being effective both in the dark and under illumination. In contrast, TiO2-based coatings showed antifungal activity only under photoperiod conditions. Controls with coatings consisting of only Ca(OH)2 were readily colonized by both fungi. The antifungal activity was monitored by direct observation with microscope, X-ray diffraction (XRD), and scanning electron microscopy (SEM), and was found to be different for the two lithotypes, suggesting that the mineral grain distribution and porosity played a role in the activity. XRD was used to investigate the formation of biominerals as indicator of the fungal attack of the limestone materials, while SEM illustrated the influence of porosity of both the limestone material and the coatings on the fungal penetration into the limestone. The coated nanosystems based on Ca(OH)2-50%ZnO and pure zincite nanoparticulate films have promising performance on low porosity limestone, showing good antifungal properties against P. oxalicum and A. niger under simulated photoperiod conditions.

The effect of water on particle size, porosity and the rate of drug release from implanted titania reservoirs.

The implantation of controlled drug release devices represents a new strategy in the treatment of neurodegenerative disorders. Sol-gel titania implants filled with valproic acid, have been used for this purpose to treat induced epilepsy in rats. The kinetics of the drug release depend on: (a) porosity, (b) chemical interactions between valproic acid and surface hydroxyl groups of titania, (c) particle size, and (d) particle size agglomerates. The concentration of water used in the hydrolysis reaction is an important variable in the degree of porosity, hydroxylation, and structural defects of the nanostructured titanium oxide reservoir. The titanium n-butoxide/water ratio was systematically varied during the sol-gel synthesis, while maintaining the amount of valproic acid constant. Characterization studies were performed using DTA-TGA, FTIR, Raman, TEM, SEM, BET, and in vitro release kinetic measurements. The particle agglomerate size and porosity were found to depend on the amount of water used in the sol-gel reaction.

Treatment of Parkinson's disease: nanostructured sol-gel silica-dopamine reservoirs for controlled drug release in the central nervous system.

INTRODUCTION: We have evaluated the use of silica-dopamine reservoirs synthesized by the sol-gel approach with the aim of using them in the treatment of Parkinson's disease, specifically as a device for the controlled release of dopamine in the striatum. Theoretical calculations illustrate that dopamine is expected to assume a planar structure and exhibit weak interactions with the silica surface. METHODS: Several samples were prepared by varying the wt% of dopamine added during the hydrolysis of tetraethyl orthosilicate. The silica-dopamine reservoirs were characterized by N(2) adsorption, scanning and transmission electron microscopy, and Fourier transform infrared spectroscopy. The in vitro release profiles were determined using ultraviolet visible absorbance spectroscopy. The textural analyses showed a maximum value for the surface area of 620 m(2)/g nanostructured silica materials. The stability of dopamine in the silica network was confirmed by infrared and (13)C-nuclear magnetic resonance spectroscopy. The reservoirs were evaluated by means of apomorphine-induced rotation behavior in hemiparkisonian rats. RESULTS: The in vitro dopamine delivery profiles indicate two regimes of release, a fast and sustained dopamine delivery was observed up to 24 hours, and after this time the rate of delivery became constant. Histologic analysis of formalin-fixed brains performed 24-32 weeks after reservoir implantation revealed that silica-dopamine implants had a reddish-brown color, suggesting the presence of oxidized dopamine, likely caused by the fixation procedure, while implants without dopamine were always translucent. CONCLUSION: The major finding of the study was that intrastriatal silica-dopamine implants reversed the rotational asymmetry induced by apomorphine, a dopamine agonist, in hemiparkinsonian rats. No dyskinesias or other motor abnormalities were observed in animals implanted with silica or silica-dopamine.

[Policies, monitoring and minors access to cigarettes in Mexico City]. / Políticas, vigilancia y acceso de los menores de edad a los cigarros en la Ciudad de México.

In Mexico and other countries, the accessibility that minors have to products derived from tobacco -mainly cigarettes- is a primary contributing factor to smoking, and is currently one of the main public health challenges worldwide. In the fight against tobacco use, effective legislation for decreasing production, distribution and the sale of tobacco products is indispensable to the creation of conditions necessary for achieving a tobacco-free society. The sale of cigarettes to minors is an act that has unique characteristics according to the particular location, particularly in Mexico City, and the time in which it is evaluated. The lack of monitoring compliance with official regulations contributes to the fact that minors directly obtain cigarettes from most of the stores.

Políticas, vigilancia y acceso de los menores de edad a los cigarros en la Ciudad de México / Policies, monitoring and minors access to cigarettes in Mexico City

En México y otros países, la accesibilidad que tienen los menores de edad a productos derivados del tabaco -sobre todo cigarros- es un factor primordial que contribuye al desarrollo del tabaquismo, que hoy día constituye uno de los principales desafíos de la salud pública en todo el mundo. En la lucha contra esta adicción, la existencia de una legislación eficaz para disminuir la producción, distribución y venta de productos derivados del tabaco es indispensable para crear las condiciones necesarias y lograr una sociedad libre de tabaco. La venta de cigarros a menores es un acto que posee características específicas en cada lugar y tiempo en que se evalúa. En particular, en el Distrito Federal la falta de vigilancia en el cumplimiento de las disposiciones oficiales contribuye a que los menores de edad consigan los cigarros en la mayoría de los comercios y los adquieran de forma directa.

Prevalencia y factores asociados a la venta de cigarros a menores de edad en el Distrito Federal / Prevalence and risk factors related to sale of cigarettes to minors in stores in Mexico City

OBJETIVO: Conocer la prevalencia y los factores asociados a la venta de cigarros a menores en el Distrito Federal. MATERIAL Y MÉTODOS: Estudio transversal realizado mediante una encuesta a expendedores de comercios que venden cigarros. Se generó un marco muestral mediante el SCINCE 2000 del INEGI, se seleccionaron probabilísticamente dos Areas Geoestadísticas Básicas (AGEB) por delegación y se realizó un censo de dichos comercios. RESULTADOS: Se visitaron 577 comercios de los cuales 73 por ciento vendió cigarros a menores, 58 por ciento vendía cigarros sueltos; 2.6 por ciento preguntó la edad y 1.2 por ciento solicitó una identificación. De los expendedores, 51 por ciento fueron hombres, 37 por ciento cursó la secundaria, 57 por ciento había fumado, 42 por ciento tenía hijos menores y 99 por ciento sabía que está prohibido vender cigarros a menores. El análisis multivariado permitió establecer un modelo explicativo, y se encontró que cuando el expendedor es hombre o se venden cigarros sueltos se incrementa entre 2 y 5 veces la posibilidad de venta, respectivamente. CONCLUSIONES: La venta de cigarros a menores en el Distrito Federal es independiente de las características del expendedor y del comercio.

[Prevalence and risk factors related to sale of cigarettes to minors in stores in Mexico City]. / Prevalencia y factores asociados a la venta de cigarros a menores de edad en el Distrito Federal.

OBJECTIVE: To identify the prevalence of the sale of cigarette to minors in stores in Mexico City. MATERIAL AND METHODS: A cross-sectional study was done applying a questionnaire to salespersons in stores that sell cigarettes. The SCINCE 2000 from INEGI was used to select and sample two Basic Geostatistical Areas (AGEB) per Delegation and a census of stores was carried out. RESULTS: A total of 577 stores were visited, 73% sold cigarettes to minors, 58% sell loose cigarettes, only 2.6% asked the buyer's age, and 1.2% requested identification. Among the salespersons, 51% were men, 37% had secondary school studies, 57% were smokers, 42% had children underage, and 99% knew that the sale of cigarettes to minors is prohibited. The multivariate analysis established an explicative model and it was discovered that when the salesperson was male or if the cigarettes were sold individually the probability of sale was 2 and 5 times higher respectively. CONCLUSIONS: The sale of cigarettes to minors in Mexico City is not associated with the personal characteristics of the salespersons or with the stores.

Principales enfoques y estrategias metodológicas empleados en la investigación del consumo de drogas: la experiencia en México / Main methodological approaches and strategies used in drug research: experience in Mexico

En la actualidad una de las características más importantes de la investigación sobre el consumo de drogas es la gran cantidad de alternativas metodológicas puestas en práctica por las cuales se ha podido estudiar este fenómeno y evidenciar las mejores respuestas. En este trabajo se revisan las principales estrategias de investigación empleadas para el estudio del problema de la demanda de drogas en muchos países y particularmente en México, destacando sus ventajas, limitaciones y posibles combinaciones. Se parte de las narraciones aportadas por la investigación antropológica; la implementación de los conteos de casos en instituciones que posteriormente se convierten en sistemas de registros de las personas que usan drogas y que llegan a los centros sanitarios o de justicia; la metodología de investigación por encuesta; los sistemas de información especializados en forma de reporte de información sobre drogas o de vigilancia epidemiológica del consumo; los estudios mediante técnicas cualitativas de investigación desarrolladas con el empleo combinado o no de técnicas de muestreo; y la integración de muchas de estas metodologías bajo el modelo de Observatorio sobre Drogas