Dear Editor,Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family,which causes dengue—a disease affecting over 400 million people annually worldwide.DENV is transmitted ...Dear Editor,Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family,which causes dengue—a disease affecting over 400 million people annually worldwide.DENV is transmitted through the bite of mosquitoes from the Aedes genus,primarily Aedes aegypti,and has a wide distribution in tropical and subtropical areas(de Souza et al.,2022).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
On the morning of October 15,people from different countries will queue up at the entrance of Centro Banamex,the international convention and exhibition center in Mexico.There are local dealers present,Brazilian build...On the morning of October 15,people from different countries will queue up at the entrance of Centro Banamex,the international convention and exhibition center in Mexico.There are local dealers present,Brazilian builders identifiable by their yellow-green,fluorescent vests,Canadian buyers carrying computer bags,and a group of Chinese individuals with aluminum alloy suitcases labeled“Foshan Ceramics”,“Yongkang Hardware”,and“Anji Bamboo Floor”.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
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
This year marks the 52nd anniversary of the establishment of diplomatic relations between China and Mexico and the 11th anniversary of the China-Mexico Comprehensive Strategic Partnership.The relationship between thes...This year marks the 52nd anniversary of the establishment of diplomatic relations between China and Mexico and the 11th anniversary of the China-Mexico Comprehensive Strategic Partnership.The relationship between these two countries has maintained a steady momentum of development,with political mutual trust increasingly being consolidated and practical cooperation in economy,trade,humanities and other areas constantly expanding.China has been Mexico’s second largest trading partner for many consecutive years,while Mexico steadily ranks as China’s second largest trading partner in Latin America.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
On April 20,the LANTING Chinese Calligraphy Culture Salon Calligraphy Exhibition and Workshop,jointly organized by China Cultural Center in Mexico and the Carranza Museum,was held in Mexico City.The exhibition present...On April 20,the LANTING Chinese Calligraphy Culture Salon Calligraphy Exhibition and Workshop,jointly organized by China Cultural Center in Mexico and the Carranza Museum,was held in Mexico City.The exhibition presents works copied and created by calligraphers such as Fang Fang,Qiu Xiaoqi,Jiang Yan,Shi Yongxin,Wang Hexuan,Dong Jie,Yan Da and Yan Kan,as well as the calligraphy works of Mexican calligraphy enthusiast Miriam and other friends.展开更多
The accuracy of interpolation models applied to groundwater depends, among other factors, on the interpolation method chosen. Therefore, it is necessary to compare different approaches. For this, different methods of ...The accuracy of interpolation models applied to groundwater depends, among other factors, on the interpolation method chosen. Therefore, it is necessary to compare different approaches. For this, different methods of interpolation of nitrate concentrations were contrasted in sixty-seven wells in an aquifer in Aguascalientes, Mexico. Four general interpolation methods were used in ArcGIS 10.5 to make the maps: IDW, Kriging, Natural Neighbor and Spline. In the modeling, only method type was varied. The input parameters (location, temporality, and nitrate concentration) were the same in the four interpolations;despite this, different maximum and minimum values were obtained for each interpolation method: for IDW, 0.2 to 22.0 mg/l, for Kriging, 3.5 to 16.5 mg/l, for Natural Neighbor, 0.3 to 21.7 mg/l and for Spline −30.8 to 37.2 mg/l. Finally, an assessment of the maps obtained was conducted by comparing them with the Official Mexican Standard (OMS), where 24 of the 67 wells were found outside the 10 mg/l that the OMS establishes as maximum permissible limit for human consumption. Taking as a starting point the measured values of nitrates (0.25 to 22.12 mg/l), as well as the spatial distribution of the interpolated values, it was determined that the Krigging method best fitted the data measured in the wells within the studied aquifer.展开更多
Neglected and underutilized species of plants(NUS)have been identified by the Food and Agriculture Organization as valuable resources for fighting poverty,hunger and malnutrition as they can help make agricultural pro...Neglected and underutilized species of plants(NUS)have been identified by the Food and Agriculture Organization as valuable resources for fighting poverty,hunger and malnutrition as they can help make agricultural production systems more sustainable and resilient.Adaptation of NUS to changing environments over several millennia has rendered most of these plants resistant to pests and climate change.In this paper,we explore the potential values of some of the Mayan fruit trees justifying conservation efforts in their native habitats.Our research was primarily based on a scoping review using Google Scholar.We considered articles published in English,Spanish and Portuguese.Our review rendered two sets of articles including those focusing on the nutritional and medicinal properties of NUS and their products,and those focusing on their uses in traditional medicine.Both sets of papers strongly support arguments for conservation of NUS.Additionally,our scoping review expands and includes a case study on the conservation of NUS,highlighting the critical role of civil society on how it can spearhead rescue efforts of botanical resources through the creation of what is possibly the first arboretum of its kind in the Americas.Among the project's key selling points was not only the rescue of an important component of Yucatan's cultural heritage but its nutritional value as well as its potential medicinal properties.Our paper is not prescriptive on how to preserve or even commercially exploit NUS.It is intended as a thought-provoking piece on the potential of a One Health approach as a multi-sectoral platform to support conservation efforts,while stimulating greater interest in the subject and encouraging more action from the academic and pharmaceutical sectors as well as civil society.展开更多
The largest accidental marine oil spill (4.9 million barrels) in the Gulf of Mexico (GoM) seabed (1600 m) caused by the sinking of the Deepwater Horizon oil rig in 2010, put to the test once again the resilient capaci...The largest accidental marine oil spill (4.9 million barrels) in the Gulf of Mexico (GoM) seabed (1600 m) caused by the sinking of the Deepwater Horizon oil rig in 2010, put to the test once again the resilient capacity of the pelagic and benthic realms of this Large Marine Ecosystem. Many are the ecological services provided by its waters (fisheries, tourism, aquaculture and fossil fuel reserves) to neighboring countries (US, Mexico and Cuba). However, the unprecedented volumes of hydrocarbons, gas and chemical dispersants (Corexit) introduced in the system, represent ecological stressors whose deleterious effects are still the subject of civil claims and scientific controversy. Presumably, the short scale effects were confined to the Gulf’s northeastern shallow waters, and the combined actions of weathering, biodegradation, and oil recovery left the system almost under pre-spill conditions. Unfortunately, surface and subsurface oil plumes were detected in the spill aftermath, and their dispersion trajectories threatened Mexico EEZ. Surface oil slicks were detected in the pristine waters of northern Yucatán, while subsurface oil plumes from the Macondo’s well blowout were dangerously advancing southwest towards key fishing grounds in the northwestern GoM. This disaster prompted the Mexican government to implement an ambitious ocean monitoring program adopting a bottom-up approach focused on building a base line for more than 42 physicochemical and biological variables for water, sediment and biota from the continental shelf-slope region of the NW GoM. Technological constraints have precluded systematic observations in the vast Mexican EEZ that could discriminate natural variability and oil seep emissions from antropic disturbances. Therefore, preliminary risk analyses relied on seasonal and historical records. Two years of field observations revealed subtle environmental changes in the studied area attributed to antropic disturbances. Waters maintained oligotrophic conditions and zooplankton and benthic infaunal biomass were also poor. Biomarkers in sediments and biota did not exceed EPA’s benchmarks, and sediment’s fingerprinting (δ13C) indicated marine carbon sources. Geomarkers revealed an active transport from the Mississippi towards the NW GoM of phyllosilicates bearing a weathered oil coating. Consequently, shelf and slope sediment toxicity begins to show an increasing trend in the region. The complexity of hydrocarbons bioaccumulation and biodegradation processes in deep waters of the GoM seems to indicate that meso-and large-scale observations may prove to be essential in understanding the capacity of the GoM to recover its ecological stability.展开更多
This paper compares monthly and seasonal rain rates derived from the Version 5 （V5） and Version 6 （V6） TRMM Precipitation Radar （TPR, TSDIS reference 2A25）, TRMM Microwave Imager （TMI, 2A12）, TRMM Combined Ins...This paper compares monthly and seasonal rain rates derived from the Version 5 （V5） and Version 6 （V6） TRMM Precipitation Radar （TPR, TSDIS reference 2A25）, TRMM Microwave Imager （TMI, 2A12）, TRMM Combined Instrument （TCI, 2B31）, TRMM calibrated IR rain estimates （3B42） and TRMM merged gauge and satellite analysis （3B43） algorithms over New Mexico （NM） with rain gauge analyses provided by the New Mexico water districts （WD）. The average rain rates over the NM region for 1998- 2002 are 0.91 mm d^-1 for WD and 0.75, 1.38, 1.49, 1.27, and 1.07 mm d^-1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d^-1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with WD rain rates and the daily TRMM mission index （TPR and TMI） suggests that the low bias of V5 3B43 for the wet months （summer to early fall） may be due to the non-inclusion of some rain events in the operational gauge analyses that. are used in the production of V5 3B43. Correlation analyses show that the WD rain rates vary in phase, with higher correlation between neighboring WDs. High temporal correlations （〉0.8） exist between WD and the combined algorithms （3B42, 3B43 and TCA for both V5 and V6） while satellite instrument algorithms （PR, TMI and TCI） are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the WD rain rates while no significant difference exists between WD and the other products. The agreements between the TRMM satellite and WD gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI （-7.4%） and TPR （-31%） rain rates （compared to V5） results in better agreement between WD estimates and TMI in winter and TPR during summer.展开更多
Hepatitis B virus(HBV)genotypes have distinct genetic and geographic diversity and may be associated with specific clinical characteristics,progression,severity of disease and antiviral response.Herein,we provide an u...Hepatitis B virus(HBV)genotypes have distinct genetic and geographic diversity and may be associated with specific clinical characteristics,progression,severity of disease and antiviral response.Herein,we provide an updated overview of the endemicity of HBV genotypes H and G in Mexico.HBV genotype H is predominant among the Mexican population,but not in Central America.Its geographic distribution is related to a typical endemicity among the Mexicans which is characterized by a low hepatitis B surface antigen seroprevalence,apparently due to a rapid resolution of the infection,low viral loads and a high prevalence of occult B infection.During chronic infections,genotype H is detected in mixtures with other HBV genotypes and associated with other co-morbidities,such as obesity,alcoholism and co-infection with hepatitis C virus or human immunodeficiency virus.Hepatocellular carcinoma prevalence is low.Thus,antiviral therapy may differ significantly from the standard guidelines established worldwide.The high prevalence of HBV genotype G in the Americas,especially among the Mexican population,raises new questions regarding its geographic origin that will require further investigation.展开更多
Forest managers and policy makers increasingly demand to have access to estimates of forest fragmentation, human accessibility to forest areas and levels of anthropogenic pressure on the remaining forests to integrate...Forest managers and policy makers increasingly demand to have access to estimates of forest fragmentation, human accessibility to forest areas and levels of anthropogenic pressure on the remaining forests to integrate them into monitoring systems, management and conservation plans. Forest fragmentation is defined as the breaking up of a forest unit, where the number of patches and the amount of expose edge increase while the amount of core area decreases. Forest fragmentation studies in Mexico have been limited to local or regional levels and have concen- trated only on specific forest types. This paper presents an assessment of the fragmentation of all forest types at the national level, their effective proximity to anthropogenic influences, and the development of an indica- tor of anthropogenic pressure on the forests areas. Broadleaf forests, tropical evergreen forests and tropical dry deciduous forests show the greatest fragmentation. Almost half （47%） of the tropical forests are in close effective proximity to anthropogenic influences and only 12% of their area can be considered isolated from anthropogenic influences. The values for the temperate forests are 23% and 29% respectively. Anthro- pogenic pressure in the immediate vicinity of anthropogenic activities is much higher in the tropical forests （75 in a scale 0-100） than in the tem- perate forests （30）. When considering these results jointly, the tropical forests, and more specifically, the tropical evergreen forests and tropical dry deciduous forests are under the greatest pressure and risks of degra- dation.展开更多
This paper presents assessments of the fragmentation of the temperate and tropical forests in Mexico at the national level for two dates 1993 and 2002.The study was based on land use and vegetation cover data sets sca...This paper presents assessments of the fragmentation of the temperate and tropical forests in Mexico at the national level for two dates 1993 and 2002.The study was based on land use and vegetation cover data sets scale 1：250,000.Two broad forest types（Temperate Forests and Tropical Forests） and five more specific forest types（Broadleaf Forests,and Coniferous Forests;Tropical Dry Deciduous Forests,Tropical Sub-evergreen Forests,and Tropical Evergreen Forests） were defined to conduct the analyses.FragStats 3.3 was used to estimate nine metrics of the spatial pattern of the forests for each forest type and date considered.The results indicate that the land cover transitions that have occurred between 1993 and 2002 have resulted in more isolated forest patches with simpler shapes in both the Temperate and Tropical Forests.The remaining Tropical Forest patches have become smaller and more numerous.In contrast,the remaining Temperate Forest patches are fewer and on average larger.Of the more specific forest types defined in this study,the Broadleaf Forests have the highest indicators of fragmentation.However these forests are usually embedded or adjacent to Coniferous Forests.Of more concern for conservation purposes are the high values of fragmentation metrics found for the Tropical Evergreen Forests and Tropical Dry Deciduous Forests,because these forest types are usually surrounded by non-forest land covers or anthropogenic land uses.展开更多
Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each fa...Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.展开更多
Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Iden...Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Identify taxonomically the pioneer vegetation on each gully section; 2) Characterize vegetation distribution preferences and 3) Assess structural/functional traits to recognize erosion control key species. Bioengineering was applied in a watershed belonging to Sierra Madre del Sur, at Oaxaca, Mexico, on eight gullies, with local support and minimal investment. "La Mixteca" is a poor ecological and socio-economic region, comparable to other regions of the world. The Initial Floristic Composition(IFC) inventory is the baseline of the successional process. The transect method was used to determine the colonization of species. Cover abundance of registered species was estimated using the semi-quantitative scale of Braun-Blanquet. This procedure was repeated in five different positions(floor, hillslopes and tops), in the cross section of the gully. Throughcorrespondence analysis and clustering, the distribution of species was analyzed. Adequate responses were obtained in soil retention(quantity) and plant cover(existence and diversity); as measurable indicators of the bioengeneering works efficiency. Occupation of soil by native species from the Tropical Deciduous Forest was favored using live barriers. We detected species guilds with spatial distribution preferences in the gullies cross section. Plant cover characterization includes: native colonizer species, herbaceous, shrubby and trees of the forest community bordering the gully area, with cover abundance and structural/functional traits, useful to protect degraded areas. This spatial occupation process of plants responds to a secondary succession in gullies, where the proposed IFC model is correctly represented through bioengineering. Natural establishment of plants was successful by traits of species such as extensive root system and sexual/vegetative reproduction.展开更多
文摘Dear Editor,Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family,which causes dengue—a disease affecting over 400 million people annually worldwide.DENV is transmitted through the bite of mosquitoes from the Aedes genus,primarily Aedes aegypti,and has a wide distribution in tropical and subtropical areas(de Souza et al.,2022).
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On the morning of October 15,people from different countries will queue up at the entrance of Centro Banamex,the international convention and exhibition center in Mexico.There are local dealers present,Brazilian builders identifiable by their yellow-green,fluorescent vests,Canadian buyers carrying computer bags,and a group of Chinese individuals with aluminum alloy suitcases labeled“Foshan Ceramics”,“Yongkang Hardware”,and“Anji Bamboo Floor”.
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This year marks the 52nd anniversary of the establishment of diplomatic relations between China and Mexico and the 11th anniversary of the China-Mexico Comprehensive Strategic Partnership.The relationship between these two countries has maintained a steady momentum of development,with political mutual trust increasingly being consolidated and practical cooperation in economy,trade,humanities and other areas constantly expanding.China has been Mexico’s second largest trading partner for many consecutive years,while Mexico steadily ranks as China’s second largest trading partner in Latin America.
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On April 20,the LANTING Chinese Calligraphy Culture Salon Calligraphy Exhibition and Workshop,jointly organized by China Cultural Center in Mexico and the Carranza Museum,was held in Mexico City.The exhibition presents works copied and created by calligraphers such as Fang Fang,Qiu Xiaoqi,Jiang Yan,Shi Yongxin,Wang Hexuan,Dong Jie,Yan Da and Yan Kan,as well as the calligraphy works of Mexican calligraphy enthusiast Miriam and other friends.
文摘The accuracy of interpolation models applied to groundwater depends, among other factors, on the interpolation method chosen. Therefore, it is necessary to compare different approaches. For this, different methods of interpolation of nitrate concentrations were contrasted in sixty-seven wells in an aquifer in Aguascalientes, Mexico. Four general interpolation methods were used in ArcGIS 10.5 to make the maps: IDW, Kriging, Natural Neighbor and Spline. In the modeling, only method type was varied. The input parameters (location, temporality, and nitrate concentration) were the same in the four interpolations;despite this, different maximum and minimum values were obtained for each interpolation method: for IDW, 0.2 to 22.0 mg/l, for Kriging, 3.5 to 16.5 mg/l, for Natural Neighbor, 0.3 to 21.7 mg/l and for Spline −30.8 to 37.2 mg/l. Finally, an assessment of the maps obtained was conducted by comparing them with the Official Mexican Standard (OMS), where 24 of the 67 wells were found outside the 10 mg/l that the OMS establishes as maximum permissible limit for human consumption. Taking as a starting point the measured values of nitrates (0.25 to 22.12 mg/l), as well as the spatial distribution of the interpolated values, it was determined that the Krigging method best fitted the data measured in the wells within the studied aquifer.
文摘Neglected and underutilized species of plants(NUS)have been identified by the Food and Agriculture Organization as valuable resources for fighting poverty,hunger and malnutrition as they can help make agricultural production systems more sustainable and resilient.Adaptation of NUS to changing environments over several millennia has rendered most of these plants resistant to pests and climate change.In this paper,we explore the potential values of some of the Mayan fruit trees justifying conservation efforts in their native habitats.Our research was primarily based on a scoping review using Google Scholar.We considered articles published in English,Spanish and Portuguese.Our review rendered two sets of articles including those focusing on the nutritional and medicinal properties of NUS and their products,and those focusing on their uses in traditional medicine.Both sets of papers strongly support arguments for conservation of NUS.Additionally,our scoping review expands and includes a case study on the conservation of NUS,highlighting the critical role of civil society on how it can spearhead rescue efforts of botanical resources through the creation of what is possibly the first arboretum of its kind in the Americas.Among the project's key selling points was not only the rescue of an important component of Yucatan's cultural heritage but its nutritional value as well as its potential medicinal properties.Our paper is not prescriptive on how to preserve or even commercially exploit NUS.It is intended as a thought-provoking piece on the potential of a One Health approach as a multi-sectoral platform to support conservation efforts,while stimulating greater interest in the subject and encouraging more action from the academic and pharmaceutical sectors as well as civil society.
文摘The largest accidental marine oil spill (4.9 million barrels) in the Gulf of Mexico (GoM) seabed (1600 m) caused by the sinking of the Deepwater Horizon oil rig in 2010, put to the test once again the resilient capacity of the pelagic and benthic realms of this Large Marine Ecosystem. Many are the ecological services provided by its waters (fisheries, tourism, aquaculture and fossil fuel reserves) to neighboring countries (US, Mexico and Cuba). However, the unprecedented volumes of hydrocarbons, gas and chemical dispersants (Corexit) introduced in the system, represent ecological stressors whose deleterious effects are still the subject of civil claims and scientific controversy. Presumably, the short scale effects were confined to the Gulf’s northeastern shallow waters, and the combined actions of weathering, biodegradation, and oil recovery left the system almost under pre-spill conditions. Unfortunately, surface and subsurface oil plumes were detected in the spill aftermath, and their dispersion trajectories threatened Mexico EEZ. Surface oil slicks were detected in the pristine waters of northern Yucatán, while subsurface oil plumes from the Macondo’s well blowout were dangerously advancing southwest towards key fishing grounds in the northwestern GoM. This disaster prompted the Mexican government to implement an ambitious ocean monitoring program adopting a bottom-up approach focused on building a base line for more than 42 physicochemical and biological variables for water, sediment and biota from the continental shelf-slope region of the NW GoM. Technological constraints have precluded systematic observations in the vast Mexican EEZ that could discriminate natural variability and oil seep emissions from antropic disturbances. Therefore, preliminary risk analyses relied on seasonal and historical records. Two years of field observations revealed subtle environmental changes in the studied area attributed to antropic disturbances. Waters maintained oligotrophic conditions and zooplankton and benthic infaunal biomass were also poor. Biomarkers in sediments and biota did not exceed EPA’s benchmarks, and sediment’s fingerprinting (δ13C) indicated marine carbon sources. Geomarkers revealed an active transport from the Mississippi towards the NW GoM of phyllosilicates bearing a weathered oil coating. Consequently, shelf and slope sediment toxicity begins to show an increasing trend in the region. The complexity of hydrocarbons bioaccumulation and biodegradation processes in deep waters of the GoM seems to indicate that meso-and large-scale observations may prove to be essential in understanding the capacity of the GoM to recover its ecological stability.
文摘This paper compares monthly and seasonal rain rates derived from the Version 5 （V5） and Version 6 （V6） TRMM Precipitation Radar （TPR, TSDIS reference 2A25）, TRMM Microwave Imager （TMI, 2A12）, TRMM Combined Instrument （TCI, 2B31）, TRMM calibrated IR rain estimates （3B42） and TRMM merged gauge and satellite analysis （3B43） algorithms over New Mexico （NM） with rain gauge analyses provided by the New Mexico water districts （WD）. The average rain rates over the NM region for 1998- 2002 are 0.91 mm d^-1 for WD and 0.75, 1.38, 1.49, 1.27, and 1.07 mm d^-1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d^-1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with WD rain rates and the daily TRMM mission index （TPR and TMI） suggests that the low bias of V5 3B43 for the wet months （summer to early fall） may be due to the non-inclusion of some rain events in the operational gauge analyses that. are used in the production of V5 3B43. Correlation analyses show that the WD rain rates vary in phase, with higher correlation between neighboring WDs. High temporal correlations （〉0.8） exist between WD and the combined algorithms （3B42, 3B43 and TCA for both V5 and V6） while satellite instrument algorithms （PR, TMI and TCI） are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the WD rain rates while no significant difference exists between WD and the other products. The agreements between the TRMM satellite and WD gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI （-7.4%） and TPR （-31%） rain rates （compared to V5） results in better agreement between WD estimates and TMI in winter and TPR during summer.
基金Supported by National Council of Science and Technology(CONACYT-FONDO SECTORIALMexico)+7 种基金Grant No.Salud-2010-1-139085to Roman SJalisco State Council of Science and Technology(COECYTJAL-Universidad de GuadalajaraGuadalajaraJaliscoMexico)Grant No.2009-1-06-2009-431to Panduro A
文摘Hepatitis B virus(HBV)genotypes have distinct genetic and geographic diversity and may be associated with specific clinical characteristics,progression,severity of disease and antiviral response.Herein,we provide an updated overview of the endemicity of HBV genotypes H and G in Mexico.HBV genotype H is predominant among the Mexican population,but not in Central America.Its geographic distribution is related to a typical endemicity among the Mexicans which is characterized by a low hepatitis B surface antigen seroprevalence,apparently due to a rapid resolution of the infection,low viral loads and a high prevalence of occult B infection.During chronic infections,genotype H is detected in mixtures with other HBV genotypes and associated with other co-morbidities,such as obesity,alcoholism and co-infection with hepatitis C virus or human immunodeficiency virus.Hepatocellular carcinoma prevalence is low.Thus,antiviral therapy may differ significantly from the standard guidelines established worldwide.The high prevalence of HBV genotype G in the Americas,especially among the Mexican population,raises new questions regarding its geographic origin that will require further investigation.
文摘Forest managers and policy makers increasingly demand to have access to estimates of forest fragmentation, human accessibility to forest areas and levels of anthropogenic pressure on the remaining forests to integrate them into monitoring systems, management and conservation plans. Forest fragmentation is defined as the breaking up of a forest unit, where the number of patches and the amount of expose edge increase while the amount of core area decreases. Forest fragmentation studies in Mexico have been limited to local or regional levels and have concen- trated only on specific forest types. This paper presents an assessment of the fragmentation of all forest types at the national level, their effective proximity to anthropogenic influences, and the development of an indica- tor of anthropogenic pressure on the forests areas. Broadleaf forests, tropical evergreen forests and tropical dry deciduous forests show the greatest fragmentation. Almost half （47%） of the tropical forests are in close effective proximity to anthropogenic influences and only 12% of their area can be considered isolated from anthropogenic influences. The values for the temperate forests are 23% and 29% respectively. Anthro- pogenic pressure in the immediate vicinity of anthropogenic activities is much higher in the tropical forests （75 in a scale 0-100） than in the tem- perate forests （30）. When considering these results jointly, the tropical forests, and more specifically, the tropical evergreen forests and tropical dry deciduous forests are under the greatest pressure and risks of degra- dation.
文摘This paper presents assessments of the fragmentation of the temperate and tropical forests in Mexico at the national level for two dates 1993 and 2002.The study was based on land use and vegetation cover data sets scale 1：250,000.Two broad forest types（Temperate Forests and Tropical Forests） and five more specific forest types（Broadleaf Forests,and Coniferous Forests;Tropical Dry Deciduous Forests,Tropical Sub-evergreen Forests,and Tropical Evergreen Forests） were defined to conduct the analyses.FragStats 3.3 was used to estimate nine metrics of the spatial pattern of the forests for each forest type and date considered.The results indicate that the land cover transitions that have occurred between 1993 and 2002 have resulted in more isolated forest patches with simpler shapes in both the Temperate and Tropical Forests.The remaining Tropical Forest patches have become smaller and more numerous.In contrast,the remaining Temperate Forest patches are fewer and on average larger.Of the more specific forest types defined in this study,the Broadleaf Forests have the highest indicators of fragmentation.However these forests are usually embedded or adjacent to Coniferous Forests.Of more concern for conservation purposes are the high values of fragmentation metrics found for the Tropical Evergreen Forests and Tropical Dry Deciduous Forests,because these forest types are usually surrounded by non-forest land covers or anthropogenic land uses.
基金Under the auspices of Mexican National Council for Science and Technology (No 2008-01-87972)
文摘Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.
基金World Wildlife Fund (WWF) for providing financial support for the conduction of the research through Oaxaca Community Foundationthe National Council for Science and Technology supported the first author through grant for two years
文摘Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Identify taxonomically the pioneer vegetation on each gully section; 2) Characterize vegetation distribution preferences and 3) Assess structural/functional traits to recognize erosion control key species. Bioengineering was applied in a watershed belonging to Sierra Madre del Sur, at Oaxaca, Mexico, on eight gullies, with local support and minimal investment. "La Mixteca" is a poor ecological and socio-economic region, comparable to other regions of the world. The Initial Floristic Composition(IFC) inventory is the baseline of the successional process. The transect method was used to determine the colonization of species. Cover abundance of registered species was estimated using the semi-quantitative scale of Braun-Blanquet. This procedure was repeated in five different positions(floor, hillslopes and tops), in the cross section of the gully. Throughcorrespondence analysis and clustering, the distribution of species was analyzed. Adequate responses were obtained in soil retention(quantity) and plant cover(existence and diversity); as measurable indicators of the bioengeneering works efficiency. Occupation of soil by native species from the Tropical Deciduous Forest was favored using live barriers. We detected species guilds with spatial distribution preferences in the gullies cross section. Plant cover characterization includes: native colonizer species, herbaceous, shrubby and trees of the forest community bordering the gully area, with cover abundance and structural/functional traits, useful to protect degraded areas. This spatial occupation process of plants responds to a secondary succession in gullies, where the proposed IFC model is correctly represented through bioengineering. Natural establishment of plants was successful by traits of species such as extensive root system and sexual/vegetative reproduction.
