Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Atmospheric nutrient deposition has serious impacts on the ecology of forests and temperate water bodies nevertheless its importance in Neotropical water bodies has hardly been studied. Here we quantify the contribution of bulk atmospheric deposition on wet surfaces of dissolved inorganic nitrogen (DIN, [NO3--N + NH4+-N]) and soluble inorganic phosphorus (SIP, [PO4-3-P]) into Lake Atitlán (Guatemala). The estimated NID and SIP loads from this direct deposition on the lake surface were respectively, 151.2 tons/year and 5.6 tons/year. With these results, we estimated that the SIP input from atmospheric deposition to Lake Atitlán is comparable to that from the lake’s main tributary rivers, whereas for DIN entry this is almost twice as much. Estimates for Lake Atitlán are higher than those reported for many lakes. Our study provides basic information towards understanding the eutrophication of Lake Atitlán, emphasizes the importance of atmospheric deposition in this process and the need for additional studies to document the process in neotropical watersheds

This research studied the membrane preparation of Cu(II) crosslinked membranes composed of cellulose and chitosan to determine its biocidal effect and efficiency to remove Escherichia coli. Water absorption, thermal degradation, and G* modulus evaluated the Cu(II) impact on the equilibrium, thermal and mechanical properties. These results showed that Cu(II) incorporation interacts with the ionic groups, inducing a structural change increasing the G* modulus by 190 %. Moreover, the cation provides thermal stability at temperatures below 200 ºC and produced surface changes to the membrane, especially to the cellulose membrane. Additionally, the cellulose-Cu(II) membranes increased 96 % their biocidal effect against E. coli. Enterobacter filtration process increased 41 % with the cation incorporation into the cellulose membrane. Therefore, this research showed the cation effect on the ionic groups in the membrane that improve the filtration properties and biocidal effect against harmful enterobacteria to humans.

Obtaining three-dimensional structural information about a protein is of utmost importance in various fields such as functional biochemistry, materials science, or biomedical sciences. Even though single-crystal X-ray diffraction is currently the gold standard for this purpose, growing said single crystal is still a bottleneck from a practical viewpoint and not fully understood from a theoretical point of view. In this article, we review, from a protein structure perspective, the way X-rays provide structural information and the physicochemical conditions that promote the formation of an adequate crystal for these experiments.

The whip ray Hypanus longus has gone from being a bycatch species to a target species in artisanal fisheries in the Pacific of Guatemala. This activity is carried out without considering essential biological criteria for its sustainable use. In addition, H. longus is a sensitive species, presenting biological characteristics such as late sexual maturity, long reproductive cycles and low fecundity. The present study contributes to the knowledge of the reproductive biology of the whip ray. During May 2019 to March 2020, 11 samplings were conducted from artisanal fishery landings in the community of Sipacate, Escuintla, in each sampling the disc width (AD), weight, sex and sexual maturation stage of H. longus were recorded. A total of 336 organisms were recorded, which presented a sex ratio of 1:1, with a female AD of M = 82.33 cm, SD = 22.24 and M = 76.91 cm, SD = 11.86 for males. From the external and internal evaluations of the reproductive apparatus, the size at sexual maturity (L50) was determined to be 88.2 and 79.3 cm AD for females and males, respectively. Finally, this study showed that 65.68% of females and 52.10% of males are caught below L50, so it is recommended to develop and implement strategies or measures to regulate fishing practices or fishing gear that allow the capture of organisms larger than 95 cm AD.

Mangroves are distributed in tropical and subtropical zones of the planet. They are located in flood zones, in high salinity and anaerobic soils. These forests are recognized as fundamental ecosystems for maintaining resilience to climate change in marine-coastal habitats, as they act as a defense against storms and tsunamis and participate in microclimatic stabilization and CO2 absorption. However, these ecosystems have declined over the years due mainly to anthropogenic factors, and it is expected that climate change will also negatively influence their conservation. In the Pacific region of Guatemala, 22,763.25 ha of mangrove forest, composed of six species, have been recorded. Despite the above, only 23% is protected within the protected areas system; therefore, mangrove vegetation cover has decreased over the years due to changes in land use, urban growth, pollution, illegal logging, among others. Likewise, there are several challenges that hinder its conservation, such as the lack of land use planning and lack of legal knowledge. It is necessary to carry out actions that promote the sustainable management of this ecosystem and to work on existing opportunities that could contribute to conservation, such as sustainable tourism and forestry incentives that can reduce the challenges posed.

Antimicrobial resistance is a global public health problem that is increasing and is reflected in the lack of efficacy of bacterial infection treatments with antibiotics in both humans and animals. The objective of this study was to evaluate the resistance to antibiotics of Escherichia coli strains isolated from pork in the municipal markets of Guatemala City. Antibiotics with the highest resistance and those with the highest sensitivity in vitro against the strains of E. coli were evaluated. A simple random sampling was carried out with proportional allocation by market, and 76 samples were collected. IMViC test was used to identify the E. coli strains, and antibiotics resistance was evaluated using the Kirby Bauer with nine different antibiotics. E. coli was isolated in 55% (42/76) of the samples. Resistance was evaluated in the 42 isolates. Antibiotic resistance was detected to tetracycline (83%), neomycin (50%), and sulfamethoxazole + trimethoprim (50 %). All isolates presented resistance to at least one antibiotic; it was determined that 83% (35/42) showed resistance to two antibiotics and 50% (21/42) showed resistance to three antibiotics or more. The sensitivity obtained was higher for ceftriaxone (91%), amikacin (83%), gentamicin (65%), and nalidixic acid (65%). In conclusion, antibiotic resistance was detected, which constitutes a risk to public health since it is found in isolated strains in food for human consumption.

The objective of this research was to explore the historical behavior of temperature, precipitation and outgoing long-wave radiation (OLR) for Guatemala, during the midsummer drought period (canícula). The methodological procedure was based on the use of the database of 38 stations of the National Institute of Seismology, Volcanology, Meteorology, and Hydrology, of Guatemala (INSIVUMEH), from the period 1971-2019. Averages were made for each region of the country; North, Caribbean, Transversal Strip, Pacific, Boca Costa, East and Altiplano. Using time series with daily temporal resolution, signals of change were evaluated, and OLR plots were made using the National Center for Environmental Prediction (NCEP) database at 2.5°x2.5° resolution. The results show that the temperature has reached in this period, finding that in some climatic regions the increase has been 1 ºC and in others 2 ºC. Likewise, it was found that the days without rain have a tendency to increase, as well as the outstanding long-wave radiation. The heat wave is a meteorological phenomenon that is being affected by climate change, and to the extent that differential heating between the Pacific and Atlantic oceans continues to be experienced, it will influence climate change for Guatemala. In conclusion, during the heat wave, there are signs of a trend toward an increase in temperature, an increase in days without rain and an increase in OLR.

Ecotoxicology studies the effect of chemical pollutants produced by anthropogenic action on different ecosystems. Beaches are an ecosystem of interest since a large amount of sedimentation occurs in these places. Therefore they have the capacity to accumulate significantly higher concentrations of chemical pollutants compared to terrestrial or aquatic ecosystems. In Guatemala, the beaches on the Pacific coast are an ideal subject for ecotoxicological studies due to the strong agricultural activity occurring in the highlands that produces a great amount of chemical pollutants, and the by-products end up in the beaches as a consequence of pluvial and rivers runoff activity. The most widely used chemical is insecticides; among them, organochlorine compounds and methyl parathion stand out, widely used in part due to their high effectiveness. The constant use of these compounds causes them to be absorbed by organisms of all levels, from primary producers to secondary consumers. Regulating the use of these compounds is of common interest because of the negative impacts on coastal ecosystems where there occurs great commercial and recreational activity from coastal communities. Mitigating the impact of these compounds will only be possible if actors influencing the Pacific littoral area become aware of the potential beach destruction and the importance of their function both for daily anthropogenic activities and ecological convergence of multiple species that depend on the beaches for their survival.

Mainwaring, Scott y Aníbal Pérez Linán,Democracias y dictaduras en América Latina. Surgimiento, supervivencia y caída (Ciudad de México: Fondo de Cultura Económica, 2019)

En los estudios sobre la historia de la vida cotidiana en México, un referente indiscutible es el trabajo de Pilar Gonzalbo; no solamente para intentar comprender los aspectos simbólicos que permean en el pasado cultural de la sociedad mexicana, sino también para seguir continuar explorando los referentes de lo cotidiano, las costumbres y la cultura en el presente. Es de esta forma que Gonzalbo presenta este libro en el 2019, el cual propone una dinámica de lectura diferente a otros textos de la autora. En este sentido, cada uno de los ocho capítulos inicia planteando interrogantes que se le han hecho a Gonzalbo durante y posteriormente al coloquio Hacia una nueva historia de la vida cotidiana, el cual fue celebrado en enero del 2018 en El Colegio de México.