The objective of this work is to reveal the meanings surrounding the discourses and narratives around drinking water services.A documentary,exploratory,and interpretive work was carried out with participants from two ...The objective of this work is to reveal the meanings surrounding the discourses and narratives around drinking water services.A documentary,exploratory,and interpretive work was carried out with participants from two colonies in central Mexico,examining community participation,public functions,and economic occupations.Central and peripheral indicators were generated,although the design of the study limited the results to the sample,suggesting an expansion of the work to include other categories of analysis such as risk perception.展开更多
In the present work, we are interested in studying the joint distributions of pairs of the monthly maxima of the pollutants used by the environmental authorities in Mexico City to classify the air quality in the metro...In the present work, we are interested in studying the joint distributions of pairs of the monthly maxima of the pollutants used by the environmental authorities in Mexico City to classify the air quality in the metropolitan area. In order to obtain the joint distributions a copula will be considered. Since we are analyzing the monthly maxima, the extreme value distributions of Weibull and Fréchet are taken into account. Using these two distributions as marginal distributions in the copula a Bayesian inference was made in order to estimate the parameters of both distributions and also the association parameters appearing in the copula model. The pollutants taken into account are ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide, and particulate matter with diameters smaller than 10 and 2.5 microns obtained from the Mexico City monitoring network. The estimation was performed by taking samples of the parameters generated through a Markov chain Monte Carlo algorithm implemented using the software OpenBugs. Once the algorithm is implemented it is applied to the pairs of pollutants where one of the coordinates of the pair is ozone and the other varies on the set of the remaining pollutants. Depending on the pollutant and the region where they were collected, different results were obtained. Hence, in some cases we have that the best model is that where we have a Fréchet distribution as the marginal distribution for the measurements of both pollutants and in others the most suitable model is the one assuming a Fréchet for ozone and a Weibull for the other pollutant. Results show that, in the present case, the estimated association parameter is a good representation to the correlation parameters between the pair of pollutants analyzed. Additionally, it is a straightforward task to obtain these correlation parameters from the corresponding association parameters.展开更多
Background: Influenza A (H1N1) is the most recent pandemic disease that has affected the human population. Objective: To evaluate knowledge and preventive measures related with this disease one year after the epidemic...Background: Influenza A (H1N1) is the most recent pandemic disease that has affected the human population. Objective: To evaluate knowledge and preventive measures related with this disease one year after the epidemic of Mexico- that took place in 2009. Material and methods: An epidemiologic survey regarding influenza A (H1N1) was conducted in June 2010 among 2541 students from the second grade of all public high schools in a borough in Mexico City. The questionnaire included items on the knowledge of the disease and practice of preventive measures. Results: Most students obtained the information from television, half of them from parents and only one fifth from teachers;72% of the participants had a favorable knowledge about the disease and the measures to avoid being infected. However, only 37% practiced such preventive measures. Conclusion: Knowledge has a positive influence on practices towards health. Parents and teachers have an important role in health education, thus efforts should be directed to involve them more intensely in health education.展开更多
A nonhomogeneous Markov chain is applied to the study of the air quality classification in Mexico City when the so-called criterion pollutants are used. We consider the indices associated with air quality using two re...A nonhomogeneous Markov chain is applied to the study of the air quality classification in Mexico City when the so-called criterion pollutants are used. We consider the indices associated with air quality using two regulations where different ways of classification are taken into account. Parameters of the model are the initial and transition probabilities of the chain. They are estimated under the Bayesian point of view through samples generated directly from the corresponding posterior distributions. Using the estimated parameters, the probability of having an air quality index in a given hour of the day is obtained.展开更多
We consider some non-homogeneous Poisson models to estimate the mean number of times that a given environmental threshold of interest is surpassed by a given pollutant. Seven different rate functions for the Poisson p...We consider some non-homogeneous Poisson models to estimate the mean number of times that a given environmental threshold of interest is surpassed by a given pollutant. Seven different rate functions for the Poisson processes describing the models are taken into account. The rate functions considered are the Weibull, exponentiated-Weibull, and their generalisation the Beta-Weibull rate function. We also use the Musa-Okumoto, the Goel-Okumoto, a generalised Goel- Okumoto and the Weibull-geometric rate functions. Whenever thought justifiable, the model allowing the presence of change-points is also going to be considered. The different models are applied to the daily maximum ozone measurements data provided by the monitoring network of the Metropolitan Area of Mexico City. The aim is to compare the adjustment of different rate functions to the data. Even though, some of the rate functions have been considered before, now we are applying them to the same data set. In previous works they were used in different data sets and therefore a comparison of the adequacy of those models were not possible. The measurements considered here were obtained after a series of environmental measures were implemented in Mexico City. Hence, the data present a different behaviour from that of earlier studies.展开更多
BACKGROUND Diabetes mellitus type 2(T2DM)is a state of hyperglycemia due to a defect in the secretion and/or action of insulin,and it represents the most common form of diabetes worldwide.In Mexico,10.3%of the adult p...BACKGROUND Diabetes mellitus type 2(T2DM)is a state of hyperglycemia due to a defect in the secretion and/or action of insulin,and it represents the most common form of diabetes worldwide.In Mexico,10.3%of the adult population have been diagnosed with T2DM and it is expanding to the pediatric population.AIM To evaluate and compare the prevalence of T2DM in the pediatric population at the Children’s Hospital,“Hospital Infantil de México Federico Gómez(HIMFG)”,at two time periods:2013 vs 2018.METHODS A comparison of two cross-sectional studies was done(2013 and 2018).The study population was comprised of children and adolescents 8-17 years old,from the Diabetes Clinic at the aforementioned institution.A comprehensive interrogation regarding family history and perinatal antecedents was performed.Complete blood work after 12 h of fasting was obtained to determine serum levels of glucose,glycated hemoglobin,lipid profile,C-peptide,and insulin.The data were analysed using the statistical software package SPSS v.23.0.A P value of<0.05 was considered statistically significant.RESULTS A total of 151 patients were included:47 from 2013,and 104 from 2018.There were age differences noted between the two periods with younger patients presenting T2DM in 2013.Also,T2DM predominated in the male sex in 55.36%in 2013 vs 32.7%in 2018.An increased prevalence of T2DM was noted from 2013 to 2018(20.2%vs 33.0%,respectively),which was a statistically significant 12.8%increase(P<0.0001).The illness phenotype was more aggressive in the 2018 group with the presence of a higher proportion of obesity,insulin resistance,and adverse lipid profiles.CONCLUSION The prevalence of T2DM at the HIMFG institution from 2013 to 2018 increased by 12.8%(20.2%vs 33.0%,respectively).The study results demonstrate the need for vigilance in T2DM trends,and to strengthen programs of healthy nutrition and physical activity as well as early detection and risk factors for obesity,data on insulin resistance,and metabolic syndrome,with the aim of preventing the development of T2DM.展开更多
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 conser...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. Brachionus 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 Lepadellapatella; 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 Braehionus： Trichocerca ratio.展开更多
It has been documented that increased vegetable consumption is associated with preventive effects in some public health problems such as obesity and some chronic noncommunicable diseases. The aim of this study was to ...It has been documented that increased vegetable consumption is associated with preventive effects in some public health problems such as obesity and some chronic noncommunicable diseases. The aim of this study was to determine the association of nutritional status with vegetable consumption in adolescents from Technical High Schools in Mexico City. A sample of 2368 adolescents was obtained who were applied a questionnaire of frequency food consumption and anthropometric measurements were taken, the nutritional diagnosis was obtained with Who Anthro Plus program. The data obtained were analyzed with the statistical package SPSS version 20.0 for Windows Statistics®. When the correlation of frequency consumption of vegetables with nutritional status, in the final phase, It found that teens who never ate vegetables were more likely to develop obesity (36.0% GI and 36.10% GC), compared with teens who consumed daily (8.9% GI and 2.10% GC), existing difference highly significant. The teenagers of the Technical High School in Mexico City in the intervention group presented a basal daily intake of 15.7% and after the intervention their intake increased to 21.3%. With respect to the control group it started with a daily intake of 12.6% to 14.9% increasing it. An increase was achieved in the daily consumption of vegetables in adolescents of both groups so it is concluded that the intervention was successful.展开更多
BACKGROUND Individuals with liver cirrhosis(LC)are likely to experience multiple infectious processes due to the immune dysfunction caused by the disease.Our hypothesis is that this group of patients is predisposed to...BACKGROUND Individuals with liver cirrhosis(LC)are likely to experience multiple infectious processes due to the immune dysfunction caused by the disease.Our hypothesis is that this group of patients is predisposed to fungal infections.To date,the incidence of spontaneous fungal peritonitis(SFP)has not been determined in Mexico;this endeavor is of great importance because many patients may be suffering from this condition without receiving targeted treatment,which may increase mortality.AIM To report the incidence of SFP in patients presenting with decompensated LC with ascites.METHODS This was a prospective,single-center,descriptive,observational and crosssectional study where patients presenting with decompensated LC with ascites were evaluated from November 2023 to May 2024 in Mexico City.Fungal cultures of ascites were performed and the samples kept in an incubator for 10 days to 14 days,and molecular tests(the API 20 C AUX test)were used for molecular characterization.RESULTS Of the 48 patients included,54.2%were women,77.1%had a comorbidity,47.9%had LC secondary to metabolic dysfunction,43.8%were classified as Child-Pugh C with a model for end-stage liver disease 3.0 median score of 22,and 10.4%were in secondary prophylaxis for spontaneous bacterial peritonitis(SBP).Only four patients had positive cultures where Candida parapsilosis and Candida albicans were isolated,with two of the four patients being positive for Rhodotorula minuta;an SBP incidence of 8.3%was thus calculated.Chronic kidney disease[P=0.012 and relative risk(RR)=15]and secondary prophylaxis for SBP(P=0.049 with RR=8.6)were statistically significant and associated with a high mortality risk(P=0.001 with RR=33).CONCLUSION The presence of infection of fungal origin in ascites in patients presenting with cirrhosis increases short-and medium-term mortality;therefore,it is recommended that fungal culture tests are performed in those patients who visit the emergency room or experience continuous admission with acute decompensation and no bacteria identified in ascites cultures,and even more so in patients with chronic kidney disease and a history of antibiotic use as prophylaxis for SBP.Further studies are needed for the identification of clinical and biochemical data that can help to define SFP so that its presence may be assessed without the need to wait for a positive fungal culture.Thus,treatment may be initiated early in the hope of having a positive impact on the prognosis in this group of patients.展开更多
Liver transplantation(LT)is the only curative treatment for end-stage liver disease.Although Mexico has made important strides in surgical capacity and institutional development,the country continues to report one of ...Liver transplantation(LT)is the only curative treatment for end-stage liver disease.Although Mexico has made important strides in surgical capacity and institutional development,the country continues to report one of the lowest LT rates in Latin America.Multiple challenges remain,including inequitable access to care,limited organ donation,and structural inefficiencies in allocation systems.To review the current status of LT in Mexico,describe historical trends,highlight significant barriers to progress,and discuss potential opportunities for program expansion.We conducted a narrative review incorporating data from the National Transplant Center(Centro Nacional de Trasplantes in Spanish),relevant peer-reviewed literature,and global benchmarks.The analysis focused on trends in liver transplant volume,donor types,etiology shifts,institutional disparities,and the impact of the coronavirus disease 2019(COVID-19)pandemic.LT activity in Mexico increased from 25 transplants in 1999 to 297 in 2023.However,over 68%of transplants are concentrated in Mexico City,and only eight centers perform more than ten LTs per year.Deceased donors account for most grafts,while living donor transplants remain rare and mostly limited to private institutions.The national waiting list functions primarily as a registry rather than a priority-based allocation system.The COVID-19 pandemic further disrupted transplant programs,particularly in the public sector.Innovative approaches such as donation after circulatory death,hepatitis C virus-positive donor utilization,and advanced perfusion technologies are currently unavailable or underutilized in Mexico.Mexico's LT system faces geographic,regulatory,and resource-related limitations.To improve outcomes and ensure equitable access,strategic reforms focused on donor expansion,centralized allocation,perfusion technologies,and standardization of care are urgently needed.展开更多
BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a tre...BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a trend observed even in our setting.The primary shared challenge has centered on achieving surgical success and immediate survival.The question arises about the medium-and long-term survival of patients with heart transplant in Mexico.AIM To present the results of the medium and long-term follow-up of heart transplant patients.METHODS This was a retrospective study of a single medical unit,and we selected patients who received heart transplants from July 21,1988 to September 30,2023.Selection criteria encompassed age,sex,and primary indication for heart transplantation across all groups.Patients with incomplete information or who died within 30 postoperative days were excluded.Data of primary pathology,ischemic,extracorporeal circulation,aortic cross-clamping times,length of ventilatory support,stay in postoperative therapy,hospitalization,and functional class were analyzed.RESULTS The causes of morbidity,mortality,and percentage of survival at 1,5,and 10 years were examined.Overall,257 heart transplants were performed during the study period.Of the total cases,22 with incomplete data and 47 who died within 30 postoperative days were excluded for the middle-and long-term survival analyses.Of the remaining 188 patients,heart transplantation was performed(males:146,females:42).The average age of the participants was 44.43±14.48 years.The primary indications included ischemic cardiomyopathy(42.55%)and dilated cardiomyopathy(39.36%).The mean durations of mechanical ventilator support,intensive care stay,and hospital stay were 57.55±103.50 hours,9.96±8.59 days,and 19.49±18.23 days,respectively.One-,five-,and ten-year survival rates were 90.7%,71.3%,and 60.3%,respectively.Of the patients,94%and 6%were in functional classes I and II,respectively.Infection and neurological hemorrhagic or ischemic stroke(26%)were the main causes of mortality in the first year.Subsequently,chronic rejection manifesting as graft vasculopathy increased in frequency(30%).CONCLUSION In our setting,heart transplantation yields medium-and long-term survival and quality of life outcomes comparable to those achieved by other international centers.展开更多
Force control merged with motion control represent the fundamental low level requirements for the most complex tasks to be performed by any robot.In particular,robust motion and force controllers allow robots to deal ...Force control merged with motion control represent the fundamental low level requirements for the most complex tasks to be performed by any robot.In particular,robust motion and force controllers allow robots to deal with real-world uncertainties among other disturbances.In this paper,an admittance-based force controller using the Active Disturbance Rejection Control approach is proposed,which allows to perform robot force control without a force sensor.In addition,a theoretical synthesis of the control law including an extended state observer for the estimation of the robot–surface force interaction and their formal stability analysis is presented.The validation of the proposal is depicted by numerical simulations using the dynamical model of a two degrees of freedom robot manipulator,for both a constant and a time-varying force control tasks with an unknown curved surface,while considering joint measurement noise and force sensors noise and an external disturbance force.展开更多
Dengue is an arboviral disease caused by the dengue virus,with 390 million infections reported annually worldwide.It is classified into two categories:dengue without or with warning signs and severe dengue.[1]Given th...Dengue is an arboviral disease caused by the dengue virus,with 390 million infections reported annually worldwide.It is classified into two categories:dengue without or with warning signs and severe dengue.[1]Given the moderate efficacy of the dengue vaccine,[2]there is an urgent necessity to design host-directed therapeutic strategies,such as the repurposing of FDA-approved drugs,to combat dengue virus infection.展开更多
BACKGROUND Liver disease is a major cause of mortality in Mexico.Liver transplantation(LT)remains severely limited,and there are no reports on equity of access.AIM To analyze geographical disparities in LT access in M...BACKGROUND Liver disease is a major cause of mortality in Mexico.Liver transplantation(LT)remains severely limited,and there are no reports on equity of access.AIM To analyze geographical disparities in LT access in Mexico.METHODS LT waitlist registrations and LT rates in Mexico from 2014 to 2023 were assessed.LT listings per million persons(pmp)were calculated.Observed-to-expected listings were calculated by controlling listings pmp and mortality rate per 10000.LT and waitlist mortality was calculated as 90-day rate,overall rate and rate per 100 person-years.We compared access to waitlist,transplantation and mortality between patients living in Mexican States with higher LT activity and those living in other States.RESULTS There were 2600 new waitlist registrations;1572 registrations(60.4%)living in Mexico City and State,Jalisco and Nuevo Leon.There were 1755 LT;92.5%of them performed in States with higher LT activity,and 1101(62.7%vs 37.3%;P<0.001)done in patients living in those States.Listings pmp in the Mexican States with high LT activity were 3.8,1.5 vs 1.2,0.6(P<0.001);observed-to-expected listings were 1.3,0.4 vs 0.4,0.2(P<0.001);LT pmp were 2.7,0.9 vs 0.7,0.5(P<0.001).After controlling for other variables,patients living in high LT activity States had a HR 1.14(95%CI:1.03-1.26;P=0.009)to be a case of transplantation after listing.CONCLUSION Geographic disparities substantially affect LT access in Mexico.The population living near Transplant Centers has a 3.2-fold higher access to the waiting list and a 3.8-fold higher likelihood of LT.Current referral system,and resource allocation need urgent revision to remove the barriers associated with geographic disparity.展开更多
Tezontle from the Anáhuac Basin became Mexico’s second IUGS Heritage Stone in August 2024.This volcanic scoria of basaltic to basaltic-andesitic composition,once considered a‘providential gift’or a‘divine mat...Tezontle from the Anáhuac Basin became Mexico’s second IUGS Heritage Stone in August 2024.This volcanic scoria of basaltic to basaltic-andesitic composition,once considered a‘providential gift’or a‘divine material’,has been used for over twenty centuries in countless architectural monuments,many of which are included in UNESCO’s World Heritage List.The abundant availability of tezontle in central Mexico,combined with its exceptional physical properties of lightness,hardness,and durability,made it the preferred material for building the massive structures of the monumental Pre-Hispanic City of Teotihuacan(1st-7th centuries).展开更多
Background: Pancreaticoduodenectomy is the standard treatment for resectable periampullary cancer. Surgical site infections(SSI) are common complications with increased morbidity. The study aimed to describe the preva...Background: Pancreaticoduodenectomy is the standard treatment for resectable periampullary cancer. Surgical site infections(SSI) are common complications with increased morbidity. The study aimed to describe the prevalence, risk factors, microbiology, and outcomes of SSI among patients undergoing pancreaticoduodenectomy. Methods: We conducted a retrospective study in a referral cancer center between January 2015 and June 2021. We analyzed baseline patient characteristics and SSI occurrence. Culture results and susceptibility patterns were described. Multivariate logistic regression was used to determine risk factors, proportional hazards model to evaluate mortality, and Kaplan-Meier analysis to assess long-term survival. Results: A total of 219 patients were enrolled in the study;101(46%) developed SSI. Independent factors for SSI were diabetes mellitus, preoperative albumin level, biliary drainage, biliary prostheses, and clinically relevant postoperative pancreatic fistula. The main pathogens were Enterobacteria and Enterococci. Multidrug-resistance rate in SSI was high but not associated with increased mortality. Infected patients had higher odds of sepsis, longer hospital stay and intensive care unit stay, and readmission rate. Neither 30-day mortality nor long-term survival was significantly different between infected and non-infected patients. Conclusions: SSI prevalence among patients undergoing pancreaticoduodenectomy was high and largely caused by resistant microorganisms. Most risk factors were related to preoperative instrumentation of the biliary tree. SSI was associated with greater risk of unfavorable outcomes;however, survival was unaffected.展开更多
Background Hedera helix L.is an invasive weed species introduced in several regions of the world,so it is relevant to study its effects on the plant community and the changes occurring after its eradication.We establi...Background Hedera helix L.is an invasive weed species introduced in several regions of the world,so it is relevant to study its effects on the plant community and the changes occurring after its eradication.We established invaded(with/without removal of H.helix)and non-invaded(with/without removal of the understory)plots to compare some community attributes in an oak forest in Mexico City and monitored them every 2 months for 1 year,taking soil samples to compare some edaphic variables between the plots.If invasive species negatively affect natural regenera-tion,seedlings of native species would be less abundant in plots invaded by H.helix than in the non-invaded ones.As invasive species modify the soil microbiota through exudates and often allelochemicals,soil chemical variables would differ between invaded and non-invaded plots.Results The abundance of native species was lower in the invaded plots,but the richness and diversity of species were not statistically different.The composition of the two invaded plots was similar to each other and more alike to that of the non-invaded plots.The species composition of the invaded plots was associated with soil potassium and phosphorus concentrations,whereas that of the non-invaded plots was more associated with soil nitrogen concentration.Conclusions Following the removal of H.helix,several native species were registered,leading to a similar species composition as in the non-invaded plots,suggesting that some vegetation recovery can be expected following H.helix removal in 1 year.展开更多
In this work, some non-homogeneous Poisson models are considered to study the behaviour of ozone in the city of Puebla, Mexico. Several functions are used as the rate function for the non-homogeneous Poisson process. ...In this work, some non-homogeneous Poisson models are considered to study the behaviour of ozone in the city of Puebla, Mexico. Several functions are used as the rate function for the non-homogeneous Poisson process. In addition to their dependence on time, these rate functions also depend on some parameters that need to be estimated. In order to estimate them, a Bayesian approach will be taken. The expressions for the distributions of the parameters involved in the models are very complex. Therefore, Markov chain Monte Carlo algorithms are used to estimate them. The methodology is applied to the ozone data from the city of Puebla, Mexico.展开更多
The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air pollution.In Mexico,the total lock...The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air pollution.In Mexico,the total lockdown period took place during the dry-hot season when biomass burning activity is enhanced.Here,we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central Mexico.The studied period covers the lockdown phases 2 and 3,and the first month of the New Normal.We applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the Megalopolis.The results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions,impacted the PBL development during phase 3 and favored transition and mixed NO_(x)-limited and VOC-limited regional regimes.This contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency estimations.Given the Megalopolis contribution to economic and societal development at national scale,our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes.A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.展开更多
BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)has recently emerged as an alternative treatment for gastric outlet obstruction(GOO)in selected patients.AIM To report the initial experience of EUS-GE ...BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)has recently emerged as an alternative treatment for gastric outlet obstruction(GOO)in selected patients.AIM To report the initial experience of EUS-GE in patients with GOO.METHODS This study was a retrospective,observational,multicenter study in which the data from 10 patients who underwent EUS-GE due to GOO between September 2021 and May 2023 were collected.We analyzed technical success,clinical success,adverse events,and survival.Technical success was defined as adequate positioning and deployment of the stent.Clinical success was defined as the patient’s ability to tolerate oral intake without vomiting 7 d after the procedure.Postprocedural adverse events were recorded.RESULTS Eleven procedures in 10 patients with GOO were included.The mean age of the patients was 67.5 years(range:56-77 years).Malignant GOO was present in 9 patients.Technical success was achieved in 9/11 procedures(82%).Among them,clinical success was achieved in 9 patients(100%).Adverse events occurred in 1 patient(9%).The median survival was 3 months(n=7;range:1-8 months).CONCLUSION EUS-GE is a feasible therapeutic option in the treatment of GOO.展开更多
文摘The objective of this work is to reveal the meanings surrounding the discourses and narratives around drinking water services.A documentary,exploratory,and interpretive work was carried out with participants from two colonies in central Mexico,examining community participation,public functions,and economic occupations.Central and peripheral indicators were generated,although the design of the study limited the results to the sample,suggesting an expansion of the work to include other categories of analysis such as risk perception.
文摘In the present work, we are interested in studying the joint distributions of pairs of the monthly maxima of the pollutants used by the environmental authorities in Mexico City to classify the air quality in the metropolitan area. In order to obtain the joint distributions a copula will be considered. Since we are analyzing the monthly maxima, the extreme value distributions of Weibull and Fréchet are taken into account. Using these two distributions as marginal distributions in the copula a Bayesian inference was made in order to estimate the parameters of both distributions and also the association parameters appearing in the copula model. The pollutants taken into account are ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide, and particulate matter with diameters smaller than 10 and 2.5 microns obtained from the Mexico City monitoring network. The estimation was performed by taking samples of the parameters generated through a Markov chain Monte Carlo algorithm implemented using the software OpenBugs. Once the algorithm is implemented it is applied to the pairs of pollutants where one of the coordinates of the pair is ozone and the other varies on the set of the remaining pollutants. Depending on the pollutant and the region where they were collected, different results were obtained. Hence, in some cases we have that the best model is that where we have a Fréchet distribution as the marginal distribution for the measurements of both pollutants and in others the most suitable model is the one assuming a Fréchet for ozone and a Weibull for the other pollutant. Results show that, in the present case, the estimated association parameter is a good representation to the correlation parameters between the pair of pollutants analyzed. Additionally, it is a straightforward task to obtain these correlation parameters from the corresponding association parameters.
文摘Background: Influenza A (H1N1) is the most recent pandemic disease that has affected the human population. Objective: To evaluate knowledge and preventive measures related with this disease one year after the epidemic of Mexico- that took place in 2009. Material and methods: An epidemiologic survey regarding influenza A (H1N1) was conducted in June 2010 among 2541 students from the second grade of all public high schools in a borough in Mexico City. The questionnaire included items on the knowledge of the disease and practice of preventive measures. Results: Most students obtained the information from television, half of them from parents and only one fifth from teachers;72% of the participants had a favorable knowledge about the disease and the measures to avoid being infected. However, only 37% practiced such preventive measures. Conclusion: Knowledge has a positive influence on practices towards health. Parents and teachers have an important role in health education, thus efforts should be directed to involve them more intensely in health education.
文摘A nonhomogeneous Markov chain is applied to the study of the air quality classification in Mexico City when the so-called criterion pollutants are used. We consider the indices associated with air quality using two regulations where different ways of classification are taken into account. Parameters of the model are the initial and transition probabilities of the chain. They are estimated under the Bayesian point of view through samples generated directly from the corresponding posterior distributions. Using the estimated parameters, the probability of having an air quality index in a given hour of the day is obtained.
基金financially supported by the project PAPIIT number IN104110-3 of the Direccion General de Apoyo al Personal Academico of the Universidad Nacional Autonoma de Mexico,Mexico,and is part of JMB’s Ph.D.partially funded by the Consejo Nacional de Ciencias y Tecnologia,Mexico,through the Ph.D.Scholarship number 210347JAA was partially funded by the Conselho Nacional de Pesquisa,Brazil,grant number 300235/2005-4.
文摘We consider some non-homogeneous Poisson models to estimate the mean number of times that a given environmental threshold of interest is surpassed by a given pollutant. Seven different rate functions for the Poisson processes describing the models are taken into account. The rate functions considered are the Weibull, exponentiated-Weibull, and their generalisation the Beta-Weibull rate function. We also use the Musa-Okumoto, the Goel-Okumoto, a generalised Goel- Okumoto and the Weibull-geometric rate functions. Whenever thought justifiable, the model allowing the presence of change-points is also going to be considered. The different models are applied to the daily maximum ozone measurements data provided by the monitoring network of the Metropolitan Area of Mexico City. The aim is to compare the adjustment of different rate functions to the data. Even though, some of the rate functions have been considered before, now we are applying them to the same data set. In previous works they were used in different data sets and therefore a comparison of the adequacy of those models were not possible. The measurements considered here were obtained after a series of environmental measures were implemented in Mexico City. Hence, the data present a different behaviour from that of earlier studies.
文摘BACKGROUND Diabetes mellitus type 2(T2DM)is a state of hyperglycemia due to a defect in the secretion and/or action of insulin,and it represents the most common form of diabetes worldwide.In Mexico,10.3%of the adult population have been diagnosed with T2DM and it is expanding to the pediatric population.AIM To evaluate and compare the prevalence of T2DM in the pediatric population at the Children’s Hospital,“Hospital Infantil de México Federico Gómez(HIMFG)”,at two time periods:2013 vs 2018.METHODS A comparison of two cross-sectional studies was done(2013 and 2018).The study population was comprised of children and adolescents 8-17 years old,from the Diabetes Clinic at the aforementioned institution.A comprehensive interrogation regarding family history and perinatal antecedents was performed.Complete blood work after 12 h of fasting was obtained to determine serum levels of glucose,glycated hemoglobin,lipid profile,C-peptide,and insulin.The data were analysed using the statistical software package SPSS v.23.0.A P value of<0.05 was considered statistically significant.RESULTS A total of 151 patients were included:47 from 2013,and 104 from 2018.There were age differences noted between the two periods with younger patients presenting T2DM in 2013.Also,T2DM predominated in the male sex in 55.36%in 2013 vs 32.7%in 2018.An increased prevalence of T2DM was noted from 2013 to 2018(20.2%vs 33.0%,respectively),which was a statistically significant 12.8%increase(P<0.0001).The illness phenotype was more aggressive in the 2018 group with the presence of a higher proportion of obesity,insulin resistance,and adverse lipid profiles.CONCLUSION The prevalence of T2DM at the HIMFG institution from 2013 to 2018 increased by 12.8%(20.2%vs 33.0%,respectively).The study results demonstrate the need for vigilance in T2DM trends,and to strengthen programs of healthy nutrition and physical activity as well as early detection and risk factors for obesity,data on insulin resistance,and metabolic syndrome,with the aim of preventing the development of T2DM.
文摘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. Brachionus 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 Lepadellapatella; 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 Braehionus： Trichocerca ratio.
文摘It has been documented that increased vegetable consumption is associated with preventive effects in some public health problems such as obesity and some chronic noncommunicable diseases. The aim of this study was to determine the association of nutritional status with vegetable consumption in adolescents from Technical High Schools in Mexico City. A sample of 2368 adolescents was obtained who were applied a questionnaire of frequency food consumption and anthropometric measurements were taken, the nutritional diagnosis was obtained with Who Anthro Plus program. The data obtained were analyzed with the statistical package SPSS version 20.0 for Windows Statistics®. When the correlation of frequency consumption of vegetables with nutritional status, in the final phase, It found that teens who never ate vegetables were more likely to develop obesity (36.0% GI and 36.10% GC), compared with teens who consumed daily (8.9% GI and 2.10% GC), existing difference highly significant. The teenagers of the Technical High School in Mexico City in the intervention group presented a basal daily intake of 15.7% and after the intervention their intake increased to 21.3%. With respect to the control group it started with a daily intake of 12.6% to 14.9% increasing it. An increase was achieved in the daily consumption of vegetables in adolescents of both groups so it is concluded that the intervention was successful.
文摘BACKGROUND Individuals with liver cirrhosis(LC)are likely to experience multiple infectious processes due to the immune dysfunction caused by the disease.Our hypothesis is that this group of patients is predisposed to fungal infections.To date,the incidence of spontaneous fungal peritonitis(SFP)has not been determined in Mexico;this endeavor is of great importance because many patients may be suffering from this condition without receiving targeted treatment,which may increase mortality.AIM To report the incidence of SFP in patients presenting with decompensated LC with ascites.METHODS This was a prospective,single-center,descriptive,observational and crosssectional study where patients presenting with decompensated LC with ascites were evaluated from November 2023 to May 2024 in Mexico City.Fungal cultures of ascites were performed and the samples kept in an incubator for 10 days to 14 days,and molecular tests(the API 20 C AUX test)were used for molecular characterization.RESULTS Of the 48 patients included,54.2%were women,77.1%had a comorbidity,47.9%had LC secondary to metabolic dysfunction,43.8%were classified as Child-Pugh C with a model for end-stage liver disease 3.0 median score of 22,and 10.4%were in secondary prophylaxis for spontaneous bacterial peritonitis(SBP).Only four patients had positive cultures where Candida parapsilosis and Candida albicans were isolated,with two of the four patients being positive for Rhodotorula minuta;an SBP incidence of 8.3%was thus calculated.Chronic kidney disease[P=0.012 and relative risk(RR)=15]and secondary prophylaxis for SBP(P=0.049 with RR=8.6)were statistically significant and associated with a high mortality risk(P=0.001 with RR=33).CONCLUSION The presence of infection of fungal origin in ascites in patients presenting with cirrhosis increases short-and medium-term mortality;therefore,it is recommended that fungal culture tests are performed in those patients who visit the emergency room or experience continuous admission with acute decompensation and no bacteria identified in ascites cultures,and even more so in patients with chronic kidney disease and a history of antibiotic use as prophylaxis for SBP.Further studies are needed for the identification of clinical and biochemical data that can help to define SFP so that its presence may be assessed without the need to wait for a positive fungal culture.Thus,treatment may be initiated early in the hope of having a positive impact on the prognosis in this group of patients.
文摘Liver transplantation(LT)is the only curative treatment for end-stage liver disease.Although Mexico has made important strides in surgical capacity and institutional development,the country continues to report one of the lowest LT rates in Latin America.Multiple challenges remain,including inequitable access to care,limited organ donation,and structural inefficiencies in allocation systems.To review the current status of LT in Mexico,describe historical trends,highlight significant barriers to progress,and discuss potential opportunities for program expansion.We conducted a narrative review incorporating data from the National Transplant Center(Centro Nacional de Trasplantes in Spanish),relevant peer-reviewed literature,and global benchmarks.The analysis focused on trends in liver transplant volume,donor types,etiology shifts,institutional disparities,and the impact of the coronavirus disease 2019(COVID-19)pandemic.LT activity in Mexico increased from 25 transplants in 1999 to 297 in 2023.However,over 68%of transplants are concentrated in Mexico City,and only eight centers perform more than ten LTs per year.Deceased donors account for most grafts,while living donor transplants remain rare and mostly limited to private institutions.The national waiting list functions primarily as a registry rather than a priority-based allocation system.The COVID-19 pandemic further disrupted transplant programs,particularly in the public sector.Innovative approaches such as donation after circulatory death,hepatitis C virus-positive donor utilization,and advanced perfusion technologies are currently unavailable or underutilized in Mexico.Mexico's LT system faces geographic,regulatory,and resource-related limitations.To improve outcomes and ensure equitable access,strategic reforms focused on donor expansion,centralized allocation,perfusion technologies,and standardization of care are urgently needed.
文摘BACKGROUND Heart transplantation is the last and best option for end-stage heart failure management.Early mortality rates have significantly decreased,enabling patients to survive longer with fewer complications,a trend observed even in our setting.The primary shared challenge has centered on achieving surgical success and immediate survival.The question arises about the medium-and long-term survival of patients with heart transplant in Mexico.AIM To present the results of the medium and long-term follow-up of heart transplant patients.METHODS This was a retrospective study of a single medical unit,and we selected patients who received heart transplants from July 21,1988 to September 30,2023.Selection criteria encompassed age,sex,and primary indication for heart transplantation across all groups.Patients with incomplete information or who died within 30 postoperative days were excluded.Data of primary pathology,ischemic,extracorporeal circulation,aortic cross-clamping times,length of ventilatory support,stay in postoperative therapy,hospitalization,and functional class were analyzed.RESULTS The causes of morbidity,mortality,and percentage of survival at 1,5,and 10 years were examined.Overall,257 heart transplants were performed during the study period.Of the total cases,22 with incomplete data and 47 who died within 30 postoperative days were excluded for the middle-and long-term survival analyses.Of the remaining 188 patients,heart transplantation was performed(males:146,females:42).The average age of the participants was 44.43±14.48 years.The primary indications included ischemic cardiomyopathy(42.55%)and dilated cardiomyopathy(39.36%).The mean durations of mechanical ventilator support,intensive care stay,and hospital stay were 57.55±103.50 hours,9.96±8.59 days,and 19.49±18.23 days,respectively.One-,five-,and ten-year survival rates were 90.7%,71.3%,and 60.3%,respectively.Of the patients,94%and 6%were in functional classes I and II,respectively.Infection and neurological hemorrhagic or ischemic stroke(26%)were the main causes of mortality in the first year.Subsequently,chronic rejection manifesting as graft vasculopathy increased in frequency(30%).CONCLUSION In our setting,heart transplantation yields medium-and long-term survival and quality of life outcomes comparable to those achieved by other international centers.
基金Julio Antonio Caballero-Mora acknowledges the CONAHCYT Scholarship number 828530。
文摘Force control merged with motion control represent the fundamental low level requirements for the most complex tasks to be performed by any robot.In particular,robust motion and force controllers allow robots to deal with real-world uncertainties among other disturbances.In this paper,an admittance-based force controller using the Active Disturbance Rejection Control approach is proposed,which allows to perform robot force control without a force sensor.In addition,a theoretical synthesis of the control law including an extended state observer for the estimation of the robot–surface force interaction and their formal stability analysis is presented.The validation of the proposal is depicted by numerical simulations using the dynamical model of a two degrees of freedom robot manipulator,for both a constant and a time-varying force control tasks with an unknown curved surface,while considering joint measurement noise and force sensors noise and an external disturbance force.
基金funded by grants Pronaii 302979A1-S-9005 CONACyT (México) from RMDA。
文摘Dengue is an arboviral disease caused by the dengue virus,with 390 million infections reported annually worldwide.It is classified into two categories:dengue without or with warning signs and severe dengue.[1]Given the moderate efficacy of the dengue vaccine,[2]there is an urgent necessity to design host-directed therapeutic strategies,such as the repurposing of FDA-approved drugs,to combat dengue virus infection.
文摘BACKGROUND Liver disease is a major cause of mortality in Mexico.Liver transplantation(LT)remains severely limited,and there are no reports on equity of access.AIM To analyze geographical disparities in LT access in Mexico.METHODS LT waitlist registrations and LT rates in Mexico from 2014 to 2023 were assessed.LT listings per million persons(pmp)were calculated.Observed-to-expected listings were calculated by controlling listings pmp and mortality rate per 10000.LT and waitlist mortality was calculated as 90-day rate,overall rate and rate per 100 person-years.We compared access to waitlist,transplantation and mortality between patients living in Mexican States with higher LT activity and those living in other States.RESULTS There were 2600 new waitlist registrations;1572 registrations(60.4%)living in Mexico City and State,Jalisco and Nuevo Leon.There were 1755 LT;92.5%of them performed in States with higher LT activity,and 1101(62.7%vs 37.3%;P<0.001)done in patients living in those States.Listings pmp in the Mexican States with high LT activity were 3.8,1.5 vs 1.2,0.6(P<0.001);observed-to-expected listings were 1.3,0.4 vs 0.4,0.2(P<0.001);LT pmp were 2.7,0.9 vs 0.7,0.5(P<0.001).After controlling for other variables,patients living in high LT activity States had a HR 1.14(95%CI:1.03-1.26;P=0.009)to be a case of transplantation after listing.CONCLUSION Geographic disparities substantially affect LT access in Mexico.The population living near Transplant Centers has a 3.2-fold higher access to the waiting list and a 3.8-fold higher likelihood of LT.Current referral system,and resource allocation need urgent revision to remove the barriers associated with geographic disparity.
文摘Tezontle from the Anáhuac Basin became Mexico’s second IUGS Heritage Stone in August 2024.This volcanic scoria of basaltic to basaltic-andesitic composition,once considered a‘providential gift’or a‘divine material’,has been used for over twenty centuries in countless architectural monuments,many of which are included in UNESCO’s World Heritage List.The abundant availability of tezontle in central Mexico,combined with its exceptional physical properties of lightness,hardness,and durability,made it the preferred material for building the massive structures of the monumental Pre-Hispanic City of Teotihuacan(1st-7th centuries).
文摘Background: Pancreaticoduodenectomy is the standard treatment for resectable periampullary cancer. Surgical site infections(SSI) are common complications with increased morbidity. The study aimed to describe the prevalence, risk factors, microbiology, and outcomes of SSI among patients undergoing pancreaticoduodenectomy. Methods: We conducted a retrospective study in a referral cancer center between January 2015 and June 2021. We analyzed baseline patient characteristics and SSI occurrence. Culture results and susceptibility patterns were described. Multivariate logistic regression was used to determine risk factors, proportional hazards model to evaluate mortality, and Kaplan-Meier analysis to assess long-term survival. Results: A total of 219 patients were enrolled in the study;101(46%) developed SSI. Independent factors for SSI were diabetes mellitus, preoperative albumin level, biliary drainage, biliary prostheses, and clinically relevant postoperative pancreatic fistula. The main pathogens were Enterobacteria and Enterococci. Multidrug-resistance rate in SSI was high but not associated with increased mortality. Infected patients had higher odds of sepsis, longer hospital stay and intensive care unit stay, and readmission rate. Neither 30-day mortality nor long-term survival was significantly different between infected and non-infected patients. Conclusions: SSI prevalence among patients undergoing pancreaticoduodenectomy was high and largely caused by resistant microorganisms. Most risk factors were related to preoperative instrumentation of the biliary tree. SSI was associated with greater risk of unfavorable outcomes;however, survival was unaffected.
基金supported by the projects:"Ecology of secondary vegetation and fungi as indicators of the conservation status of a temperate forest in the Magdalena river basin,Mexico City"PAPIME PE201817"Effect of anthropic disturbances on functional diversity in a temperate forest within Mexico City"PAPIIT IN211118.
文摘Background Hedera helix L.is an invasive weed species introduced in several regions of the world,so it is relevant to study its effects on the plant community and the changes occurring after its eradication.We established invaded(with/without removal of H.helix)and non-invaded(with/without removal of the understory)plots to compare some community attributes in an oak forest in Mexico City and monitored them every 2 months for 1 year,taking soil samples to compare some edaphic variables between the plots.If invasive species negatively affect natural regenera-tion,seedlings of native species would be less abundant in plots invaded by H.helix than in the non-invaded ones.As invasive species modify the soil microbiota through exudates and often allelochemicals,soil chemical variables would differ between invaded and non-invaded plots.Results The abundance of native species was lower in the invaded plots,but the richness and diversity of species were not statistically different.The composition of the two invaded plots was similar to each other and more alike to that of the non-invaded plots.The species composition of the invaded plots was associated with soil potassium and phosphorus concentrations,whereas that of the non-invaded plots was more associated with soil nitrogen concentration.Conclusions Following the removal of H.helix,several native species were registered,leading to a similar species composition as in the non-invaded plots,suggesting that some vegetation recovery can be expected following H.helix removal in 1 year.
文摘In this work, some non-homogeneous Poisson models are considered to study the behaviour of ozone in the city of Puebla, Mexico. Several functions are used as the rate function for the non-homogeneous Poisson process. In addition to their dependence on time, these rate functions also depend on some parameters that need to be estimated. In order to estimate them, a Bayesian approach will be taken. The expressions for the distributions of the parameters involved in the models are very complex. Therefore, Markov chain Monte Carlo algorithms are used to estimate them. The methodology is applied to the ozone data from the city of Puebla, Mexico.
文摘The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air pollution.In Mexico,the total lockdown period took place during the dry-hot season when biomass burning activity is enhanced.Here,we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central Mexico.The studied period covers the lockdown phases 2 and 3,and the first month of the New Normal.We applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the Megalopolis.The results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions,impacted the PBL development during phase 3 and favored transition and mixed NO_(x)-limited and VOC-limited regional regimes.This contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency estimations.Given the Megalopolis contribution to economic and societal development at national scale,our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes.A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.
文摘BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)has recently emerged as an alternative treatment for gastric outlet obstruction(GOO)in selected patients.AIM To report the initial experience of EUS-GE in patients with GOO.METHODS This study was a retrospective,observational,multicenter study in which the data from 10 patients who underwent EUS-GE due to GOO between September 2021 and May 2023 were collected.We analyzed technical success,clinical success,adverse events,and survival.Technical success was defined as adequate positioning and deployment of the stent.Clinical success was defined as the patient’s ability to tolerate oral intake without vomiting 7 d after the procedure.Postprocedural adverse events were recorded.RESULTS Eleven procedures in 10 patients with GOO were included.The mean age of the patients was 67.5 years(range:56-77 years).Malignant GOO was present in 9 patients.Technical success was achieved in 9/11 procedures(82%).Among them,clinical success was achieved in 9 patients(100%).Adverse events occurred in 1 patient(9%).The median survival was 3 months(n=7;range:1-8 months).CONCLUSION EUS-GE is a feasible therapeutic option in the treatment of GOO.
