Search

• Agave marmorata is important for the production of a traditional alcoholic beverage called mezcal and pulque. • The immersion frequency and culture medium volume had an effect during in vitro multiplication of A. marmorata. • The immersion frequency and culture medium volume had an effect on chlorophyll content of A. marmorata. • The Temporary Immersion Bioreactor is an alternative for micropropagation of A. marmorata. Agave marmorata is an important wild species in Mexico for mezcal and pulque production. Propagation by suckers and seeds is not sufficient to restore wild populations. The aim of this study was to develop a protocol for large-scale micropropagation of A. marmorata using a temporary immersion bioreactor (TIB). The effect of liquid medium using a TIB and semi-solid medium as the control treatment was compared. Different immersion frequencies and culture medium volumes per explant were evaluated in the TIB. In all treatments, the percentage of hyperhydricity, number of shoots per explant, shoot length, and total chlorophyll and carotenoid content were evaluated. In addition, the survival rate during acclimatization was evaluated. The results obtained show that the TIB with an immersion of 2 min every 8 h and with a culture medium volume of 50 mL had the best developmental parameters, with 19.60 shoots per explant, a shoot length of 1.74 cm and a percentage of hyperhydricity of 3.33 %. The highest chlorophyll content was observed in temporary immersion every 8 h, with 100, 75 and 50 mL of culture medium per explant. Regarding carotenoid content, the highest content was found at the 8 and 12 h immersion frequencies, with the culture medium volumes of 100, 75 and 50 mL per explant. For acclimatization, no differences were found in the survival rate between the culture systems evaluated. In conclusion, this study demonstrates that the use of a TIB is an alternative for large-scale micropropagation of A. marmorata. [ABSTRACT FROM AUTHOR]

Multidisciplinary information such as geophysical, hydraulic, geological, and hydrogeological information combined with GIS can be a powerful tool to better understand aquifers. The aim of this paper is to assess groundwater pollution risk through regional hydrogeological and local hydrogeophysical models built from multidisciplinary information and geophysical well logs. Once the regional model of the Toluca Valley Aquifer (Mexico) was built, the critical area (CA) of the aquifer was identified through features such as fractures and faults, pollution sources, subsidence, groundwater table depletion, and well density, which were transformed into GIS with multicriteria analysis. With the CA a local hydrogeophysical model was set to extract lithological information and compute the intrinsic vulnerability (IV) through the Dar Zarrouk parameters according to the AVI-Fr method which considers the influence of fractures and faults as preferential paths for pollutants. On the other hand, the potential harmful load (PHL) of the different pollution sources was estimated with the POSH method. Finally, with the relation between the IV and PHL, risk pollution map could be made. The results of this study show that different areas are exposed to pollution risk due to their proximity to fractures, oil and gas subsurface infrastructure and high pumping ratios and their relationships. The available geophysical data and multidisciplinary information were powerful tools for identifying the critical area of the TVA and proposing actions to mitigate or control excessive withdrawals for sustainable management. [ABSTRACT FROM AUTHOR]

Objective: To establish a time series model correlating vanilla production with temperature variation to forecast vanilla production in Mexico. Design/methodology/approach: Data on vanilla production in Mexico (Tons) and the annual average temperature were obtained for the period 1985-2020. An ARIMA model was constructed; Granger causality test was conducted to determine the effect of temperature on vanilla production, in addition to evaluating the orthogonal response of the model. A forecast for vanilla production was made for the period 2020-2040. Results: ARIMA (1,1,1) model was found, and the influence of temperature on vanilla production was determined. Both thermal variation and the production of the last three years determine current production. A reduction in the quantity of tons of vanilla produced in the coming years is expected. It is considered that this cultivation is highly sensitive to sudden increases or decreases in temperature. Limitations on study/implications: Vanilla cultivation is sensitive to temperature variation; therefore, in the face of climate change, it is considered necessary to take a series of actions in the present. These actions encompass a genetic perspective, new cultivation methods and locations, as well as technological investment. Findings/conclusions: Vanilla production is influenced by temperature variation and is sensitive to sudden increases or declines. If actions are not taken in the present, a reduction in the national production of vanilla in Mexico is expected due to climate change. [ABSTRACT FROM AUTHOR]

We investigated microcrustaceans inhabiting arsenic contaminated and non-contaminated freshwater to identify potential bioindicators of arsenic contamination in the tropical freshwater of Matehuala in northern Mexico. We collected water, sediment, and zooplankton, at five sampling points during three sampling campaigns. We determined water temperature, pH, electrical conductivity, dissolved oxygen, alkalinity, salinity, and total arsenic concentration in water. Additionally, we determined total arsenic and arsenic speciation in sediment samples. We identified microcrustaceans and determined abundance, richness, and Shannon Index. We also investigated relationships and correlations between physiochemical and ecological variables. Results showed that arsenic concentrations in freshwater ranged from 0.001 to 53.23 mg/L, while total arsenic in sediments ranged from 10.37 to 2472.84 mg/kg as As + 5. Six microcrustacean species were found in highly and moderately contaminated water (Latonopsis australis, Eucyclops chihuahuensis, Acanthocyclops americanus, Pleuroxus (Picripleuroxus) quasidenticulatus, Macrocyclops albidus, and Paracyclops chiltoni), while five species were found in arsenic-free water (Simocephalus punctatus, Alona glabra, Eucyclops leptacanthus, M. albidus, and P. quasidenticulatus). An inverse relationship was observed between microcrustacean richness and arsenic. However, the scope of the data did not allow for a strong and significant correlation. Nevertheless, among the species inhabiting As-free water, S. punctatus showed potential to be further tested as a bioindicator of As contamination in Matehuala. Identification of potential bioindicators could help monitor water quality and increase understanding of the incorporation and toxicity of As in freshwater-sensitive and freshwater-metallotolerant microcrustaceans, which, in turn, might help us to understand As incorporation in the food web. [ABSTRACT FROM AUTHOR]

Description and morphological analysis of copepods inhabiting a water body with high arsenic concentrations (32.79 to 62.29 mg L−1) were performed to identify some effect on the development of individuals due to the arsenic concentrations. Detailed morphology of prosomal and urosomal appendages along the development of the specimens was considered. The results showed that the freshwater copepod Paracyclops novenarius Reid, 1987 inhabits this water body, and previously, it was recorded as Paracyclops chiltoni (Thomson GM, 1882) on this site. Moreover, this becomes the first record of P. novenarius in Mexico. Morphological analysis showed a normal and stable development along the different instars, different arsenic concentrations in the media, and different sampled dates between the analyzed specimens, suggesting that the high arsenic concentrations do not affect the morphology of P. novenarius, including all its development and adult instars, which differs from other copepods and other groups such as Cladocera and Rotifera, where morphological changes due to metals and metalloids have been observed but in low concentrations of these elements. The results of this study contribute to the existing reports of the genus Paracyclops (Claus 1893) in Mexico and could provide information for environmental impact assessments on aquatic systems. [ABSTRACT FROM AUTHOR]

Simple Summary: Climate change has intensified high environmental temperatures, subjecting farm animals to heat stress conditions. In this study, the thermoregulatory responses of Blackbelly adult ewes and female lambs, during the summer under tropical conditions, in southern Mexico were analyzed. The combination of temperature and relative humidity in summer in tropical conditions causes heat stress in hair ewes, resulting in thermoregulatory problems. To counteract these effects, females modify their physiological constants to avoid reproductive and productive problems under these production conditions. High environmental temperatures cause heat stress in ewes, resulting in thermoregulatory problems. In this study, the thermoregulatory responses of Blackbelly adult ewes (G1, n = 14) and female lambs (G2, n = 7), during the summer under tropical conditions, in southern Mexico were analyzed. Different physiological variables and skin temperatures (ST) of the ewes were recorded. Breathing frequency (BF) values were similar between groups at 116.73 ± 33.598 bpm (G1) and 113.661 ± 34.515 bpm (G2) (p > 0.05). In the case of skin elasticity (SE), there were no significant differences between the time of day and the age of the ewes (p > 0.05). Significant differences were observed between groups for BF, rectal temperature (RT), and heart rate (HR) values (p < 0.05). All ST values, for both groups, were significantly higher during the afternoon (p < 0.001). In general, all Blackbelly adult ewes and female lambs during the summer present severe heat stress conditions as a result of an increase in physiological constants and ST. It is concluded that all ewes thermoregulate body temperature by modifying different physiological variables to counteract the effect of heat stress. [ABSTRACT FROM AUTHOR]

Groundwater occurrence in semi-arid regions is variable in space and time due to climate patterns, terrain features, and aquifer properties. Thus, accurate delineation of Groundwater Potential Zones (GWPZs) is essential for sustainable water resources management in these environments. The present research aims to delineate and assess GWPZs in a semi-arid basin of San Luis Potosi (SLP), Mexico, through the integration of Remote Sensing (RS), Geographic Information System (GIS), and Analytic Hierarchy Process (AHP). Seven thematic layers (geology, lineament density, land use and land cover, topographic wetness index (TWI), rainfall, drainage density, and slope) were generated in raster format. After the AHP procedure and rank assignment, the thematic layers were integrated using the raster calculator to obtain the GWPZs map. The results indicated that 68.21% of the area is classified as low groundwater potential, whereas 26.30% is classified as moderate. Validation was done by assessing the water residence time data from 15 wells distributed in the study area. Furthermore, the Receiver Operating Characteristics (ROC) curve was obtained, indicating a satisfactory accuracy prediction (AUC = 0.677). This study provides valuable information for decision-makers regarding the conservation and sustainable management of groundwater resources. [ABSTRACT FROM AUTHOR]

Objective: To analyze the international commercialization competitiveness of the main flowers grown in Mexico compared to United States of America (USA). Design/methodology/approach: The cumulative growth rate of the production variables of the main flowers cultivated in Mexico from 2000 to 2020 was calculated. The country’s flower trade balance was evaluated. The revealed comparative advantage index (IVCR) of the Mexican floricultural sector was compared with the American IVCR. Results: Mexican floriculture has expanded in the last two decades; therefore, the 2000-2020 cumulative growth rates of the production variables in most of the flowers studied were positive. It is also a high-income activity. Although only 10.11 thousand ha are used by this sector, the four species of flowers analyzed had a 5.51-billion Mexican pesos production value (2020). Likewise, its trade balance has been in surplus and, in most of the years analyzed, its balance was greater than 90% of the value of exports. In addition, it is competitive in the international market: in 2020, the IVCR of Mexican flowers in the US market was 0.96 and, in the overall period of this study, it has been greater than 0.8. Study Limitations/Implications: Changes to the Harmonized System Codes hinder the evolutionary analysis of the tariff codes. The IVCR determines if the national market is competitive or not in the international market, but it does not establish which factors would provide competitiveness to the country. Findings/Conclusions: Floriculture in Mexico has increased in the last two decades. The production value of all the flowers studied increased during the period analyzed. In general terms, the Mexican floricultural market is competitive in the international market; additionally, the different Mexican flowers included in this research have a competitive advantage in the US market. [ABSTRACT FROM AUTHOR]

Domestic production of basic products has failed to meet the demand of the population. In addition to this, imports of bread wheat and rice have been increasing since the trade liberalization in Mexico. This research analyzes the performance of the support price policy and PROCAMPO through the methodology that consists of the calculation of the food dependence index, where production, population, imports, exports and product yield are considered to quantify it, this with the aim of observing in what magnitude each policy contributes to achieving the objective set by the Federal Government of achieving food self-sufficiency in the country. The analysis period includes 2011-2020 to observe more broadly the behavior of the national production of the selected products (bread wheat and rice), the results obtained in the analysis indicate that the direct payment policy (PROCAMPO) is more effective in increasing the productivity of the Mexican countryside than the support price policy; however, despite the efforts the main objective is still not achieved, there are still major efforts to improve the conditions of the Mexican countryside, because there is no reduction in imports of the products studied, they continue to oscillate in more than 50% of national consumption and have not shown significant reductions that indicate an improvement in the results of the implementation of the program. [ABSTRACT FROM AUTHOR]

Delineating spring protection zones is key to managing groundwater. This work presents a proposal for delineating spring protection zones (SPZs) that uses hydrogeological, topographical, land use, and climate characteristics as a basis to protect springs located in fractured volcanic media from potential contamination processes. This was accomplished through five stages: (1) identification of hydrogeological characteristics of the environments in which springs are located and physicochemical properties of water, (2) delineation of spring potential catchment zones, (3) estimation of spring recharge zones in the potential catchment zones, (4) SPZ proposal based on annual recharge analysis for each spring, and (5) projection of future land use and climate change scenarios. The result was a proposal of three typically established zones for protecting springs: SPZ1 was defined by a 50-m radius around springs, SPZ2 was delineated based on spring annual recharge zone estimate, and SPZ3 was considered the remainder of potential catchment zone. By delineating these zones, more suitable protection measures can be identified based on trends in land use and climate changes, measures which would thereby aid in sustainable use of these types of springs. [ABSTRACT FROM AUTHOR]

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Perfiles Latinoamericanos is the property of FLACSO - Mexico (Facultad Latinoamericana de Ciencias Sociales) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose -- This purpose of this paper is to test if social network theory applies in a developing country like Mexico. A set of Mennonite milk processors is tested against non-Mennonite milk processors along five dimensions of firm performance. Design/methodology/approach -- A sample of 61 milk processing firms is tested utilizing logistic regression where regression variables are financial fluidity, number of employees, age of the enterprise, productivity and efficiency, and other business related difficulties. Findings -- It appears that social network theory in the form of religious ties, applies in Mexico as it does in much different industrialized economies that have typically been the setting for previous tests of social network theory. Research limitations/implications -- Secondary data rather than primary data were used for this test, as a result, the usual battery of tests on research variables that ascertain validity and reliability could not be conducted. Moreover, the data covered only milk processors in northern Mexico. Practical implications -- It would appear that organizations might benefit from the open observance of religious practice at work, contrary to the secular approach of the past. Originality/value -- This paper may represent one of the first tests of network theory utilizing religious ties in Mexico. [ABSTRACT FROM AUTHOR]

Abstract: In tropical and subtropical zones, coastal lagoons are surrounded by mangrove communities which are a source of high quantity organic matter that enters the aquatic system through litter fall. This organic matter decomposes, becoming a source of nutrients and other substances such as tannins, fulvic acids and humic acids that may affect the composition and productivity of phytoplankton communities. Sontecomapan is a coastal lagoon located in the southern Gulf of Mexico, which receives abundant litter fall from mangrove. To study the phytoplankton composition and its variation in this lagoon from October 2002 to October 2003, we evaluated the concentrations of dissolved folin phenol active substances (FPAS) as a measure of plant organic matter, salinity, temperature, pH, O2, N-NH4 +, N-NO3 −, P-PO4 3−, Si-SiO2, and phytoplanktonic cell density in different mangrove influence zones including the three main rivers that feed the lagoon. Nutrients concentrations depended on freshwater from rivers, however these varied seasonally. Concentrations of P-PO4 3−, N-NH4 + and FPAS were the highest in the dry season, when maximum mangrove litter fall is reported. Variation of these nutrients seemed to depend on the internal biogeochemical processes of the lagoon. Blooms of diatoms (Skeletonema spp., Cyclotella spp. and Chaetoceros holsaticus) and dinoflagellates (Peridinium aff. quinquecorne, Prorocentrum cordatum) occurred seasonally and in the different mangrove influence zones. The high cell densities in these zones and the occurrence of certain species and its ordination along gradient of FPAS in a canonical correspondence analysis, suggest that plant organic matter (i.e. mangrove influence) may contribute to phytoplankton dynamics in Sontecomapan lagoon. [Copyright &y& Elsevier]

Copyright of Revista Mexicana de Economía Agrícola y de los Recursos Naturales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Burnout syndrome (BS) is characterized by emotional fatigue, loss of personal identity and loss of personal realization feelings. BS is frequent among professionals that assist people (health care workers) and among those that have interpersonal contact; the occupational characteristics are among BS contributing factors. The objective was to ascertain BS prevalence among nurses affiliated to the San Luis Potosí General Hospital. A cross-sectional survey was carried out with a groups of nurses who gave their informed consent to participate. The Brief Questionnaire of Burnout version standardized for Mexico was used to collect the information. This version explores the following areas: emotional fatigue, loss of personal identity and personal realization. Also, participants answered three questionnaires about their socio-demographic characteristics, occupational satisfaction, family variables and emotional dysfunction. 70 licensed nurses participated. The BS was common among participants. Some variables related to BS were: age older than 30 years, being female, being married, housekeeping work, absenteeism due to illness, serious depression and occupational dissatisfaction. Nurses working at the emergency room and in critical care services had BS more often. The Burnout syndrome has a high prevalence among licensed nurses. Interventions to decrease and to avert BS are needed. [ABSTRACT FROM AUTHOR]

The objectives of this study were to compare five animal models and one sire model and to estimate genetic parameters for body weight at birth from a Creole chicken population in Yucatan, Mexico. Information on body weights was obtained from 758 chickens, progeny of 35 roosters and 140 Creole hens bought from 15 rural communities in Yucatan. Chicks were weighed individually at birth and identified using numbered metallic wing-bands. Roosters and hens were fed with a commercial diet containing 16.5% of crude protein. Data were analyzed by restricted maximum likelihood procedures using five animal models and one sire model. Animal model 1 considered the animal as the only random effect. Models 2 and 3 included, in addition to the additive direct effect of the animal, the common environmental or additive maternal effects, respectively. Model 4 fitted both, the additive maternal and common environmental effects. Model 5 was the same as model 4, except that the covariance between the direct and maternal additive effects was included. The sire model included the rooster and hen within the rooster effects. Animal models 2, 4 and 5 were the best models. Estimates of direct heritability decreased when the maternal additive or common environmental effects were fitted to the model. Estimates of additive direct, maternal and environmental heritabilities from model 5 were: 0.20, 0.18 and 0.35, respectively. The correlation between direct and maternal additive genetic effects was -0.60. This result indicates that the choice of the best animal model should consider the genetic and environmental effects that the reproductive scheme in the population allows, in order to have more precise heritability estimates. [ABSTRACT FROM AUTHOR]

Species of Chaetoceros with less than four setae per cell are not common. In this study, five different taxa presenting this characteristic were found in the Sontecomapan lagoon, Mexico, a small tropical coastal lagoon on the Gulf of Mexico: Chaetoceros minimus, C. subtilis var. abnormis f. abnormis, C. subtilis var. abnormis f. simplex, C. throndsenii var. throndsenia, and C. thondsenii var. trisetosa. Using an electron microscope to make observations of C. subtilis var. abnormis f. simplex made evident the absence of rimoportulae suggesting a close relationship to C. minimus. According to our observations, we believe that the reduction in the number of setae in Chaetoceros is related to solitary forms. The five species studied here are associated with quiet brackish-water enclosed environments and can be considered worldwide-distributed organisms. [ABSTRACT FROM AUTHOR]

The objective of the study was to describe the clinical, epidemiological profile and conditional incubation period in a group of transfusion-associated HIV-infected (TAHI) patients seen in five national tertiary care centres in Mexico from 1983 to April 1998. Date of transfusions, AIDS diagnoses, opportunistic infections and malignancies were collected. The incubation period was estimated through a non-parametric conditional analysis. One hundred and fifty-seven TAHI cases were analysed. The frequency of TAHI by year of transfusion was: 0.6% in 1980 and 1981, 4.5% in 1984, 22.4% in 1985, 54.5% in 1986, 10.3% in 1987, 0.6% in 1988, 1.9% in 1989 and 1990, 1.3% in 1993 and 0.6% in 1994 and 1996. The median incubation period was 4.3 years. A well-defined epidemic period of HIV-infection among blood-recipients was identified that coincided with the HIV-epidemic among paid donors. TAHI patients in Mexico developed AIDS in a shorter time than that described for other populations. [ABSTRACT FROM AUTHOR]

Copyright of Archivos de Cardiología de México is the property of Publicidad Permanyer SLU and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Asian tiger mosquito Aedes albopictus (Skuse), is one of the most invasive mosquito species worldwide. In Mexico it is now recorded in 12 states and represents a serious public health problem, given the recent introduction of Chikungunya on the southern border. The aim of this study was to analyze the population genetics of A. albopictus from all major recorded foci, and model its ecological niche. Niche similarity with that from its autochthonous distribution in Asia and other invaded countries were analyzed and its potential future expansion and potential human exposure in climate change scenarios measured. We analyzed 125 sequences of a 317 bp fragment of the cyt b gene from seven A. albopictus populations across Mexico. The samples belong to 25 haplotypes with moderate population structuring (Fst = 0.081, p < 0.02) and population expansion. The most prevalent haplotype, found in all principal sites, was shared with the USA, Brazil, France, Madagascar, and Reunion Island. The ecological niche model using Mexican occurrence records covers 79.7% of the country, and has an 83% overlap with the Asian niche projected to Mexico. Both Neotropical and Nearctic regions are included in the Mexican niche model. Currently in Mexico, 38.6 million inhabitants are exposed to A. albopictus , which is expected to increase to 45.6 million by 2070. Genetic evidence supports collection information that A. albopictus was introduced to Mexico principally by land from the USA and Central and South America. Prevalent haplotypes from Mexico are shared with most invasive regions across the world, just as there was high niche similarity with both natural and invaded regions. The important overlap with the Asian niche model suggests a high potential for the species to disperse to sylvatic regions in Mexico. [ABSTRACT FROM AUTHOR]