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The high concentrations of particulate matter (PM) in the atmosphere have adverse effects on both the environment and human health, as well as on urban and faunal biodiversity. Short-term events, such as the burning of fireworks, attributable to human activity, result in a significant and rapid increase in PM concentration levels within the atmosphere. We present findings derived from observations made using low-cost PM sensors deployed as part of the Environmental Monitoring Network in Querétaro, Mexico. These sensors utilize the Environmental Geo Monitoring Stations (EMGA) device, developed by the Institute of Geosciences at UNAM. The observation period spanned from 10 December 2023 to 10 January 2024, encompassed the Christmas and New Year holidays, and focused on PM2.5 concentrations, and a comparison with a similar period from 10 February 2024 to 10 March 2024 considered a typical activity period in the area. The results reveal two substantial increases in PM2.5 concentrations (from less than 50 µg/m3 to more than 340 µg/m3) over time and spatial distribution during this period, with notable increases observed during the festive season coincident with the Christmas and New Year celebrations. Specifically, prolonged periods exceeding up to 6 h were noted on festivity days. This research offers insight into the effects, trends, and spatial–temporal distribution of pollutants within the city of Queretaro, which may be used as a reference for other cities around the world. [ABSTRACT FROM AUTHOR]

We present the Latin-American Paleomagnetic Online Database (LAPOD), which includes an online tool for consulting and visualizing paleomagnetic data. This platform allows users to search, filter, and query over 2000 paleomagnetic data entries from locations across Latin America, including North America (Mexico and the Southwestern USA), Central America, and South America. Paleomagnetic data has been pre-validated for geographic locations and ages, enhancing its reliability for users. The platform features a robust database engine with up to 26 filters, allowing users to perform queries with high precision and avoiding data duplication, and to download data in various formats for personal use. It also offers graphical visualization of some data directly on screen. Color indicators are used to indicate data quality and magnetic polarity. All data included in LAPOD are properly referenced to their original authors, with links to the original published articles. LAPOD is proposed as a community-driven platform, allowing users to contribute their data and provide comments on their own and others' data. This fosters discussion about the reliability of paleomagnetic data and finally enhances our knowledge of the Earth's magnetic field in the region. This collaborative approach supports the development of new regional models of paleosecular variation with improved reliability. It may be repeated for other regions in the world, and ultimately lead to improved global field models. To access the platform, please visit: https://paleomagnetismo.org/pmagdb/ • Perform personalized queries to paleomagnetic data from Latin America and surrounding countries. • Access to Paleomagnetic (declination, inclination and intensity) data from geological and archaeological materials. • Advanced 26 filters to perform a customized search on paleomagnetic data. • Download the datasets to analyze the paleomagnetic data. • LAPOD is designed to be a user-friendly interface to access data. [ABSTRACT FROM AUTHOR]

Historical information on wildfires and dendrochronological studies offer meaningful clues about fire and climate regimes, factors that affect forest structure and dynamics. This study aimed to determine the effect of fire history on vegetation dynamics and successional pathways of areas under different fire management policies in the Lagunas de Montebello National Park (LMNP), Chiapas, México. The selected study sites were El Parque area under fire exclusion policies since 1961; Tziscao-inhabited area under fire prohibition since 1984; and Antelá area with a traditional agricultural fire management history. A Pinus oocarpa ring-width chronology was used as a proxy for climate variability to which wildfire occurrence was mapped and to determine the establishment patterns of this dominant species. Current vegetation composition and structure and fuel loads were determined to characterise the study sites. Large wildfires, like those occurring in 1984 and 1998, were associated with periods of high humidity followed by intense droughts; they were linked to strong El Niño events and severely impacted the LMNP. Vegetation dynamics indicated simplification of mesophyll forest (climax) to pine-oaksweetgum forests, with Pinus dominating the overstorey in all sampling sites. Pine, oak and sweetgum species were the dominant juvenile trees in Antelá, El Parque and Tziscao, respectively. Late-successional seedlings (i.e., Prunus) were present in Antelá and El Parque, while were absent from Tziscao where several wildfires had occurred. Fuel accumulation in sites within protected areas subject to fire exclusion policies was very high (40-68 t ha-1); in contrast, it was the lowest in rural Antelá (24 t ha-1). Considering vegetation vulnerability to wildfires associated with extreme humid-dry climate events, increased fire hazard due to fuel accumulation, and the socio-ecological impacts of these events, we recommend revising the fire exclusion policies currently implemented in the LMNP and applying an integrated fire management approach that incorporates local socio-ecological conditions. [ABSTRACT FROM AUTHOR]

Introduction: Burns are part of the management of introduced grasses in Chiapas, Mexico, and this may derive in forest fires. Objectives: To determine fuel load, fire behavior, CO2 emissions, and to get firefighting security issues for jaragua (Hyparrhenia rufa Nees.) grasslands and savannas. Methods: An artificial jaragua grassland and an artificial jaragua savanna were studied at the California and Flores Magón communities, respectively, in La Sepultura Biosphere Reserve. Were measured pre and post-fire fuel loads. Six prescribed burns (three heading and three backing fires) were conducted in each, grassland and savanna, and were measured meteorological as well as fire behavior variables. Emissions were estimated multiplying the consumed fuel load by an emission constant. Results: In the grassland, were obtained the following averages: fuel load, 6.214 t/ ha; residual load, 0.107 t/ha, and CO2 emission, 10.449 t CO2/ha. For the savanna, were recorded 14.119, 2.161 and 20.460 t CO2/ha, respectively, without differences for the pre and post-fire fuel loads between heading and backing fires. For the grassland, the heading fires reached 3.92 m, 1.83 m and 22.3 m/min for flame length, flame depth and fire propagation rate, while for backing fires such values were, respectively: 1.07, 0.23 and 0.67 m/min, with significant differences. For the savanna, heading fires yielded 5.89 m (flame length), 1.53 m (flame depth) and 45.5 m/min (propagation rate), while for backing fires that values were 2.21, 0.76 and 2.8 m/ min, also with significant differences. Conclusions: Under the studied environmental conditions, particularly in the savanna, fire behavior is dangerous so a good prescription and more care must be taken for conducting controlled or prescribed burns. For forest fires, direct firefighting by the head of the fire must be avoided, for is too dangerous; instead it is recommended a firefighting by the back of the fire as well as waiting for a backing fire-advance of it after the fire reaches a ridge. [ABSTRACT FROM AUTHOR]

The genus Lupinus has potential use in ecological restoration, agroforestry systems, and commercial forest plantations, due to its ability to fix nitrogen to the soil. The physical dormancy of its seeds allows their storage for long periods. Its longevity is partially known. The objective of this study was to analyze the weight, moisture content, germinative capacity, germinative energy, and viability of seeds of L. bilineatus Benth., after they had been stored for 15 years in a glass jar at room temperature (fresh, approximately 10-15 °C), and without light. A randomized complete block design was used for the experiment and the ANOVA was performed with a mixed procedure. The treatments were: control, mechanical scarification (sanding with sandpaper), and chemical (5, 10, 30, and 40-min immersion in sulfuric acid), with a day/night regime of 25/20 °C, and a 12-h photoperiod (fluorescent light). The results were compared with those obtained 15 years before. The following results were obtained: 66 766.2 seeds per kg, with a 6.60% humidity (fresh basis), 45% viability (tetrazolium salts test), and a 3.2 d germinative energy. There were significant differences among the treatments (p ≤0.0001). Scarification with sandpaper favored a greater germination (48.9%). The annual decline rate of the germinative capacity was 2.24%. Scarification can eliminate the physical dormancy of the seeds. Scanning microscopy showed that the seed coat has cuticle, macrosclereids, osteoesclereids, and parenchyma. The seed of L. bilineatus without coat contains 52.15, 9.21, and 2.83% raw protein, raw fat, and raw fiber, respectively. [ABSTRACT FROM AUTHOR]

The great wealth of volcanism along the Trans Mexican Volcanic Belt (TMVB) and the need to improve the secular variation curve of the Earth magnetic field of the region is the aim of this research. 300 oriented cores from 33 sites and 21 individual cooling units were acquired from Sierra de Chichinautzin volcanic field (ChVF) and Sierra de Santa Catarina (SSC). Directional analysis and rock magnetic experiments were performed (e.g. thermal demagnetization, hysteresis loop, susceptibility vs temperature), achieving 21 new averaged palaeomagnetic directions. New results are consistent with the previous studies on the same cooling unit. We compiled all the palaeomagnetic studies performed on the ChVF, updating age and calculating an average direction per cooling unit and estimating an overall mean direction for the ChVF (Dec = 359.1°, Inc = 35.3°, N = 33, k = 21.6, α95 = 5.5°, Plat = 87.7° N, Plong = 227.4° E, K = 31.8, A95 = 4.5°). Afterwards, we compiled all the previous palaeomagnetic studies along the whole TMVB with age ranging from 0 to 1.5 Ma, and constrained the directional analyses by specific quality criteria such as well-defined age, number of samples and quality of kappa) on the cooling unit consistency. The mean direction and virtual geomagnetic pole (VGP) estimated for the TMVB, during the periods 0–40 ka and 0–1.5 Ma, are close to the geographic pole, supporting the validity of the geocentric axial dipole hypothesis. The directional results of this study also fit well with the predictions at Mexico City of the models SHA.DIF.14k and CALS10k2 calculated for the last 14 ka. The dispersion of the VGP's on the TMVB are also consistent with the expected values proposed by different models of palaeosecular variation. However, large gaps in the temporal record remain that should be filled by further palaeomagnetic studies. [ABSTRACT FROM AUTHOR]

The present study employs petrology, rock magnetics, and paleointensity on four lava flows (seven sites) of the El Jorullo volcano; a historical (1759–1766 AD) cinder cone in the Michoacán-Guanajuato Volcanic Field. El Jorullo lava flows cover an extensive area of ∼10.8 Km2, and a volume ∼0.35 Km3. Rock-magnetic experiments and microscopic observations reveal pseudo-single domain size Ti-poor titanomagnetite as the main carrier of magnetization in all sampled flows. Notably the calculated mean direction from all the sites show a slight westwards bias when compared against the secular variation global models. The mean paleo-direction for the El Jorullo historical eruption is: Dec = 2.5°, Inc = 37.5°, kappa = 214, α95 = 1.8, N = 31; the Virtual Geomagnetic Pole has Plat = 87° N, Plong = 307° E, Kappa = 260, A95 = 1.6; paleointensity data: 45.4 ± 3.6 μT; and Virtual Dipole Moment: 10.3 ± 1 × 1022 Am2. The paleodirections and the paleointensity values from these lava flows are well-constrained and reliable. These results allow to improve the accuracy and reliability of the global and regional secular variation models available for the last centuries. • Well defined rock magnetic characterization of the lava flows. • Paleodirections and paleointensity values from these lava flows are well-constrained and reliable. • Results improve accuracy and reliability of the global and regional secular variation models available for the last centuries. [ABSTRACT FROM AUTHOR]

Fire is considered a relevant ecological factor, however, human alterations of fire regime facilitate more destructive wildfires. The aims of this work were to model probability of tree mortality and to identify the factors associated with leader shoot growth in a prescribed burn area and in a nearby wildfire area in a juvenile Pinus hartwegii Lindl. stand in central Mexico. A prescribed burn was carried out in 10-ha stand in March 2012, and compared with a close area affected by a wildfire occurred one week later, as well as with a nearby unburned area taken as control. A logistic model was used to estimate the probability of mortality, and a linear regression model was employed to investigate factors related to leader shoot growth. No tree mortality was recorded in the unburned control. In contrast, mortality was 6% in the prescribed burn and 66.9% in the wildfire area. The probability of mortality was influenced by stem char height (positively, p<0.0001), tree height (negatively, p=0.0443), and diameter at breast height (negatively, p<0.0001). The variables that had more influence on leader shoot growth were stem char height (negatively, p<0.0001) and tree height (positively, p<0.0001). This work supports evidence of the feasibility of using low intensity prescribed burns in this ecosystem with minimum effects on young tree mortality. [ABSTRACT FROM AUTHOR]

In Mexico, research about the seedling quality of tree species has only increased as of 1999; despite its importance for successful plantations, there are still few species with validated data in plantation sites. In order to compare the seedling quality attributes of Abies religiosa (Kunth) Schltdl. et Cham. plants from La Soledad, Tlaxcala and Santa Ana Tlacotenco, Mexico City, in nursery conditions and further evaluations of increments in the field site, we cultivated the trees from both provenances in containers in the nursery of San Luis Tlaxialtemalco, Xochimilco, Mexico City. The studied variables were height, diameter at root collar, shoot and root dry weights, total dry weight, shoot to root ratio, slenderness coefficient, and Dickson quality index, along with the root growth potential. We established the experimental plantation in Santa Ana Tlacotenco. Six and 12 months after planting, we evaluated the survival of the trees; and 12 months after planting, we measured height, diameter at root collar, and shoot, root, and total dry weights. In both, the nursery and the plantation, we used a randomized block design with four repetitions. We analyzed the data with ANOVA; we used a Tukey test (p≤0.05) to compare the data and Pearson correlations between all the variables during the plantation and one year after the plantation. The provenance did not affect the indicators of seedling quality nor the survival one year after the plantation. The mean values of the seedlings in the nursery were: 4.5 mm (diameter at root collar), 29.2 cm (height), 6.0 g (total dry weight), 6.6 (slenderness coefficient), 1.4 (shoot to root ratio), and 0.8 (Dickson quality index). The test of root growth potential produced 22 new roots. In the trees from Mexico City, we observed a significant correlation between the shoot to root ratio and the root dry weight one year after the plantation. In the trees from Tlaxcala, the initial Dickson quality index correlated significantly with the increase in the root dry weight one year after planting. These values represent the seedling quality and allow us to predict a high survival in plantations of A. religiosa in the area of study. [ABSTRACT FROM AUTHOR]

Abstract The lithic in the Cerro Colorado tephra deposits is dominated by clasts from shallow country rocks for a diatreme not well mixed, or, by a combination of material that reflects the relative proportions of country rock in a well-mixed diatreme. The clasts in a tephra ring bed might be ideal to use the paleomagnetic study to determine the emplacement temperature. We report emplacement temperature ranges of pyroclastic lithic fragments from the Cerro Colorado Tuff Ring in the El Pinacate Volcanic Field, Sonora, northwestern Mexico. Paleomagnetic analyses, particularly the thermoremanent magnetization procedure was carried out in 38 small cores, drilled from the 10 to 30 cm in size lithic fragments. It estimates the emplacement temperature ranges of the juvenile basaltic cauliflower bombs and not-juvenile diverse blocks produced in the phreatomagmatic eruption. Titanomagnetite and titanohematite are the main magnetic carriers, along with titanomaghemite. The 22 emplacement temperatures determined in this study are grouped in three temperature ranges, low (310–370 °C), medium (400–460 °C) and high (>500 °C). The low and medium temperature samples show two or more components, while the high temperature samples have, in general, only one component. This wide range of emplacement temperature could be related to the composite thermal history of the pyroclastic material incorporated in the water saturated pyroclastic flow deposit. The comparison of the mean direction of the secondary magnetization component with the secular variation curve of the global model SHA.DIF.14, suggests an age of 3915 ± 59 yr. BP. Highlights • The clasts in a tephra ring bed might be ideal to use the paleomagnetic study to determine the emplacement temperature. • The emplacement temperature was determined from Cerro Colorado Tuff Ring in El Pinacate Volcanic Field, Sonora, NW Mexico. • The emplacement temperatures are grouped in three temperature ranges, related to the composite thermal history of the pyroclastic material. • An eruption age of 3915 ± 59 yr. BP was determined using the secondary component of magnetization with the global model curve SHA.DIF.14k. [ABSTRACT FROM AUTHOR]

Forest fires and agricultural burns contribute to global climate change, and the latter is a tool that reduces CO2 emissions. The objective of this study was to evaluate the consumption of surface fuels, fire behavior, and emissions in prescribed burns. The hypothesis was that fires affect more fuels and produce more emissions than prescribed burns. Prescribed burns were applied in six randomly-established experimental plots in a tropical oak woodland in Chiapas, Mexico: three heading and three backing fires. Measurements and estimates included: initial and residual fuel loads, consumption factors, and CO2 emissions. Wind speed and direction, temperature and relative humidity, fire spread rate, and flame length were recorded during the burns. In a forest fire, the flame length and the residual fuel load were determined. The t- and the Wilcoxon (under lack of normality) tests were applied. In the heading and backing fires, there were significant differences in the fire spread rate (3.63 and 0.59 m min-1), but there were none in the flame length (0.91 and 0.72 m). The flame length of fires reached 1.94 m, but burns had different results. The total fuel loads in backing and heading fires were 28.393 and 35.512 t ha-1, without differences between them; the consumption factors for backing and headingfires and forest fire reached 92.7, 87.5, and 97.2 %, without showing any difference; however, the forest fire affected aerial fuels. The CO2 emissions reached 44.53, 51.14, and 53.78 t CO2 ha-1. The prescribed burns help to reduce emissions, because their intensity and severity are lower than those of forest fires. Consequently, since burns affect a smaller surface, they help to prevent fires and to reduce emissions. [ABSTRACT FROM AUTHOR]

The Central America Volcanic Arc shows an intense and continuous volcanic activity spanning the last 10 ky because of the subduction processes parallel to the Middle America Trench. Several volcanic events have occurred during the Plio-Holocene, along the coastal Nicaraguan region, characterized either by explosive or effusive activity. Volcanic deposits were emplaced at high temperatures and have similar basaltic-andesitic composition suggesting a long-lived magma chamber but emplaced and cooled by different mechanisms. We present paleodirectional and paleointensity results of four lava flows, and the paleointensity recorded on different pyroclastic deposits in the Managua-Masaya region, western Nicaragua. For each, we characterize the rock magnetic properties as a function of temperature and magnetic field. Absolute paleointensity experiments estimated a mean range from 38.6 to 52.9 μT; and a mean virtual axial dipole moment from 9.4 × 1022 Am2 to 12.8 × 1022 Am2. Two paleomagnetic ages were determined for two cooling units: (1) the Masaya Caldera Walls with an age range of 8580–8535 BP, and (2) a dating for a lava flow from Momotombo Volcanic Complex estimated of 1500–1600 CE. These results are consistent with the expected values according to the actual paleosecular variation global models, and with the regional stratigraphy and historical ages. The high reliability of paleointensity determination from these pyroclastic deposits and lava flows suggest that both are suitable for paleomagnetic dating. Finally, an accurate chronology of the volcanic events, will improve the understanding of the evolution of the volcanism and their implications for volcanic risk on the region. This knowledge will help to decrease the considerable hazard for the population on the surrounding areas. • First paleomagnetic study of Holocene volcanism in Nicaragua. • Rock magnetic and microscopy results show the differences on magnetic response on lava flows and pyroclastic density currents • Directional data analysis match with the expected GAD for the Holocene in Central America. • Mean paleointensities on a range from 38.6 to 52.9 μT and VADM from 9.4×1022 to 12.8×1022 Am2 for the Holocene in Nicaragua • Paleomagnetic dating of two volcanic structures on a range of 8580–8535 BP and 1500 to 1600 CE were determined. [ABSTRACT FROM AUTHOR]

Water quality is a relevant factor for production of forest species, but it is not always taken into account in nurseries in Mexico. One of the parameters of water quality is its acidity. The objective of this work was to study the response in morphology and concentration of ions and cations in leaf tissue of Pinus cembroides Zucc., to different water pH and concentrations of compounds in fertigation solutions. Plants were cultivated in a nursery in 170 cm3 containers with a substrate made of peat moss (40 %), vermiculite (30 %) and agrolite (30 %). The experimental design was completely randomized blocks with two factors and two levels: 1) pH of irrigation water (8 and 5.5); 2) fertilization (ppm): establishment (50-123-73 of N, P, K for both levels), growth (100-22-83 and 150-33-125) and finalization (15- 41-109 and 30-82-218); these levels of fertilization were denominated low and high. The effect of factors and their interaction was determined with an ANOVA (p⩽0.10). The morphological variables and quality indexes evaluated were height, diameter, shoot dry weight, root dry weight, Dickson quality index, shoot/root ratio, lignification index, slenderness index and leaf nutrient concentration. There was no response in terms of morphological variables or indexes. There was, however, a response in leaf nutrient concentration. The highest leaf concentration of K (p⩽0.001) was obtained with high fertilization at both levels of pH, and the highest concentration of Mn with higher fertilization without adjusting pH (8.0). The highest concentrations of Ca (p⩽0.092), Mg (p⩽0.074), and Cu (p⩽0.093) occurred with high fertilization and pH=5.5, and that of Zn (p⩽0.001) was with low fertilization and adjusted pH. There were interactions between fertilization and water pH for K (p⩽0.005), Ca (p⩽0.1) and Zn (p⩽0.039). The highest nutrient concentrations were obtained with water pH=5.5 and high fertilization. [ABSTRACT FROM AUTHOR]

La calidad del agua es un factor relevante para la producción de especies forestales, pero no siempre se toma en cuenta en viveros de México. Uno de los parámetros de calidad de agua es su acidez. El objetivo de esta investigación fue estudiar la respuesta en la morfología y en la concentración de iones y cationes en el tejido foliar de Pinus cembroides Zucc., a diferentes niveles de pH de agua y concentraciones de compuestos en las soluciones de ferti-irrigación. Las plantas fueron cultivadas en vivero, en contenedores de 170 cm3, con sustrato a base de turba de musgo (40 %), vermiculita (30 %) y agrolita (30 %). El diseño experimental fue en bloques completamente al azar, con dos factores y dos niveles por factor: 1) pH del agua de riego (8 y 5.5); 2) fertilización (ppm): establecimiento (50-123-73 de N, P, K para ambos niveles), crecimiento (100-22-83 y 150-33-125), y finalizador (15-41-109 y 30-82-218); estos niveles de fertilización se denominaron bajo y alto. El efecto de factores y su interacción fue determinado con un ANDEVA (p⩽0.10). Las variables morfológicas e índices de calidad evaluados fueron: altura, diámetro, peso seco aéreo, peso seco de raíz, índice de calidad de Dickson (ICD), relación parte aérea/raíz, índice de lignificación, índice de esbeltez y concentración nutrimental foliar. No hubo respuesta en variables morfológicas ni en índices, pero sí en concentración nutrimental foliar. La mayor concentración foliar de K (p⩽0.001) fue con la fertilización alta en ambos niveles de pH, y la de Mn con fertilización alta y sin ajuste de pH (8.0). Las mayores concentraciones de Ca (p⩽0.092), Mg (p⩽0.074) y Cu (p⩽0.093) ocurrieron con fertilización alta y pH=5.5, y la de Zn (p⩽0.001) fue con fertilización baja y pH ajustado. Hubo interacciones entre fertilización y pH del agua para K (p⩽0.005), Ca (p⩽0.1) y Zn (p⩽0.039). Las mayores concentraciones nutrimentales fueron para agua con pH=5.5 y la fertilización alta. [ABSTRACT FROM AUTHOR]

García et al. (2021) analyzed paleomagnetic data from the Trans-Mexican Volcanic Belt (TMVB) for paleosecular variation analysis and stated that their work was the first systematic approach of that kind since 2005. This is incorrect, as Rodriguez-Trejo et al. (2019) published a much more comprehensive study, both in terms of the number of paleomagnetic data and their spatial extension within the TMVB, and this work was not even cited by Garcia et al. (2021). Additionally, Garcia et al. (2021) reported 11 allegedly new paleomagnetic directions from lava flows of monogenetic volcanoes and did not mention that 7 of these had been studied before by the same group (Maciel et al., 2014). Results are often similar, but in some cases dramatically different, now interpreted as being related to geomagnetic excursions or of different polarity. Such appalling differences between repeat studies of the same monogenetic volcano or lava flow must be declared, discussed, and in case of only minor differences statistical tests should be applied to check if such results could be combined into one direction. If such data are boldly different, they must be explained convincingly or otherwise resolved by additional sampling of the corresponding volcano. We also report numerous errors in the references, text, figures, and tables of that work. [ABSTRACT FROM AUTHOR]

Maternal low-protein diets (LP) impair pancreatic β-cell development, resulting in later-life failure and susceptibility to type 2 diabetes (T2D). We hypothesized that intrauterine and/or postnatal developmental programming seen in this situation involve altered β-cell structure and relative time course of expression of genes critical to β-cell differentiation and growth. Pregnant Wistar rats were fed either control (C) 20% or restricted (R) 6% protein diets during pregnancy (1st letter) and/or lactation (2nd letter) in four groups: CC, RR, RC, and CR. At postnatal days 7 and 21, we measured male offspring β-cell fraction, mass, proliferation, aggregate number, and size as well as mRNA level for 13 key genes regulating β-cell development and function in isolated islets. Compared with CC, pre- and postnatal LP (RR) decreased β-cell fraction, mass, proliferation, aggregate size, and number and increased Hnf1a, Hnf4a, Pdx1, Isl1, Rfx6, and Slc2a2 mRNA levels. LP only in pregnancy (RC) also decreased β-cell fraction, mass, proliferation, aggregate size, and number and increased Hnf1a, Hnf4a, Pdx1, Rfx6, and Ins mRNA levels. Postnatal LP offspring (CR) showed decreased β-cell mass but increased β-cell fraction, aggregate number, and Hnf1a, Hnf4a, Rfx6, and Slc2a2 mRNA levels. We conclude that LP in pregnancy sets the trajectory of postnatal β-cell growth and differentiation, whereas LP in lactation has smaller effects. We propose that LP promotes differentiation through upregulation of transcription factors that stimulate differentiation at the expense of proliferation. This results in a decreased β-cell reserve, which can contribute to later-life predisposition to T2D. [ABSTRACT FROM AUTHOR]

Pine-oak forests cover 14.2 million hectares in Mexico, a country that has the richest pine and oak diversity in the world. These diverse forests are a source of goods and services for rural and urban society, but they are being degraded and deforested. A cause of degradation is the alteration of the fire regime caused by fire exclusion or excessive burning. Little information is available on how to restore ecologically appropriate fire regimes in Mexican pine-oak ecosystems. Less is known about the fire ecology of the oak species. To determine which of these pine-oak and oak forests are firemaintained and which are sensitive to fires, and to provide insight into the restoration of appropriate fire regimes, this paper categorizes oak species according to the following characteristics: climate and type of vegetation, environment and succession, fire regime, growth form, vegetative regeneration, regeneration niche, acorn size, foliage type, bark thickness, subgenus, and understory. Frequent low-intensity surface fires are recommended for the restoration and maintenance of many of these forests and to reduce the ecological, economic, and firefighting impacts that result from large-magnitude wildfires, although it is recognized that for some species of pine and oak, periodic high-intensity fires are required. Because the source of more than 40% of the wildfires in Mexico is agricultural and grazing activities, it is essential to consider the needs of rural communities who use fire for their livelihood, and how burning might help restore and maintain these ecosystems. [ABSTRACT FROM AUTHOR]

I propose several broad fire regimes and provide an analysis of fire ecology for the principal vegetation types in Mexico. Forty percent of Mexican ecosystems are firedependent (pine forests, several oak forests, grasslands, several shrublands, savannas, palm lands, wet prairies, "popal" and "tular" swamps), 50% are fire-sensitive (tropical rain forests and tropical seasonal forests, tropical cloud forests, mangrove, fir forests, several oak forests, and several shrublands), and the remaining 10% fall into fire-influenced (such as several gallery forests) and fire-independent categories (shrublands in most xeric environments, very high-altitude prairies). I also present an analysis of current fire-management trends, highlighting the trend toward integral fire management, which merges prevention and control, community-based fire management, and ecological fire management. [ABSTRACT FROM AUTHOR]

Abstract: The capacity of A, X and clinoptilolite zeolites to remove Co2+ or Cs+ is compared. The Co2+ and Cs+ exchanged zeolites were thermally and combustion treated until vitrification. Desorption of cobalt and cesium from those treated solids was tested by lixiviation with 1N NaCl solution. As the calcining temperature increased, the cristallinity of cobalt and cesium exchanged zeolites decreased. The retention of cobalt and cesium in thermally treated exchanged zeolites is slightly higher than in combustion treated zeolites ignited at 1000°C. The difference is attributed to the compounds (amorphous and crystalline) formed during the treatments. The cobalt and cesium content were determined by neutron activation analyses and the solids were characterized by X-ray diffraction, IR-spectroscopy and scanning electron microscopy (SEM). [Copyright &y& Elsevier]

The Lagunas de Montebello National Park, Chiapas, Mexico, is one of the most important protected areas in terms of ecology and the provision of ecosystem services in the state of Chiapas; however, it lacks long-term climate information to support comprehensive plans for the conservation of endangered species and ecosystem restoration actions. The objectives of this work were to analyze: (i) the interannual variability of the annual rings of Pinus oocarpa Schiede in the Lagunas de Montebello National Park, as influenced by climate; and (ii) the ocean-atmosphere phenomena influence on both the interannual variability of the total ring-width series. A dendrochronological series of P. oocarpa was built for the period 1857-2018 (162 years), which indicates the presence of extreme hydroclimatic events in the region. Of these, the 1998 drought was a milestone for the management of this natural area due to the high-intensity fires that affected the area and caused unprecedented ecological, social, and economic damage in the site history. The climatic variables with the greatest influence on the annual radial increase of the species are precipitation and maximum temperature in winter-spring, when growth is positively associated with precipitation and negatively associated with temperature, attributed to increases in evapotranspiration. El Niño Southern Oscillation was the phenomenon with the highest correlation with climatic variability and the radial growth of the species, in frequencies of less than five years, although the positive influence of the Atlantic Multidecadal Oscillation was also assessed annually. Global warming, characterized by increasing temperature, threatens the persistence of plant communities in the study area; therefore, knowing its impact on the growth of species of economic importance is essential to support conservation actions. [ABSTRACT FROM AUTHOR]

In 2017, at the foot of the Tlaloc volcano, occurred the largest forest fire in the State of Mexico (2500 ha), with surface and crown (canopy) phases, on plantations of various species and various types of vegetation. Studies on the effects of fires on trees serve to define mortality and whether or not restoration will be required in an affected area. The hypothesis was: the greater the intensity and severity of the fire and the smaller the size of the trees, the greater the probability of mortality. The objective of the study was to establish the fire severity and dasometric variables that influence the probability of both mortality and resprouting in Casuarina equisetifolia L. plantations affected by fire. The study was conducted at the Experimental Forestry Station “Las Cruces” (Universidad Autónoma Chapingo, State of Mexico). In 2019, 442 trees (15 sites of 100 m² ) were sampled in 50 ha of plantations affected by the fire. Records were made on whether the trees were alive or dead, normal diameter, bark thickness, height, height at the base of the original crown, height of the fire scar on the trunk, height of crown scorch and presence of resprouting. The statistical analysis consisted of logistic regressions, using the Proc Logistic procedure of the SAS program. The average tree mortality was 63 %. The variable that was directly related (p ≤ 0.05) to the probability of mortality was the height of the scar above the trunk. The dasometric variables inversely related (p ≤ 0.05) with the probability of mortality were: height, normal diameter and bark thickness. For resprouting probability, there was an inverse relationship (p ≤ 0.05) with normal diameter, bark thickness and height of scar on the trunk. It is concluded that casuarina is a fire sensitive species. [ABSTRACT FROM AUTHOR]

The Pinacate Volcanic Field is a Neogene volcanic sequence at the northwestern part of Mexico. This paleomagnetic study (directional and paleointensity) will continue to improve the global paleomagnetic databases. It is the first full vector paleomagnetic analysis within the more than 400 volcanic structures of the Pinacate Volcanic Field, e.g. scoria, cinder cones, large 'pahoehoe' and 'aa' lava flows. A total of 140 oriented standard paleomagnetic cores from 16 sites of lava flows were collected. Rock magnetic experiments such as thermomagnetic analyses show that Ti-poor titanomagnetite is the main magnetic carrier of the remanence. Microscopy of oxide minerals supports this observation. Parameters from hysteresis and FORC diagrams suggest pseudo-single domain grain sizes or a mixture of single and multidomain particles. The directional analysis of 11/12 volcanic structures provides a mean paleomagnetic direction and corresponding mean paleomagnetic pole (calculated from the site VGPs): Dec = 0.1°, Inc = 54.5°, n = 11, α 95 = 6.7°, k = 48, Plat = 86.5°, Plong = 247.8°, A 95 = 7.5°, respectively. The mean paleointensity, obtained by using the Thellier-Coe protocol, and estimated from seven volcanic structures is 42.2 ± 3.6 μT, and VDM is 8.1 × 1022Am2. The obtained directions are compatible with the Late Pleistocene paleodirection as expected from the geocentric axial dipole (GAD) field. The virtual geomagnetic pole scatter (Sb) was calculated at 13.5° which is consistent with the paleosecular variation value expected from El Pinacate latitude. • First paleomagnetic study of the Late Pleistocene volcanism from El Pinacate Volcanic field. • Mineral microscopy and rock magnetic results suggest Ti-poor titanomagnetite as the main magnetic carrier of remanence. • Mean paleointensity, 42.2 ± 3.6 μT and VDM 8.1 × 1022 Am2 were determined for the volcanic activity of the last 50 ka. • Directional and paleointensity analysis match with the expected GAD for the last 50 ka in Mexico. • Secular variation of the earth magnetic field was compared with global compilations published. [ABSTRACT FROM AUTHOR]

The evaluation of reforestation for ecological restoration purposes in an area requires the comparison of similarity indicators with nearby reference forests. The objective of this study was to compare the vegetal composition, structure, falling debris, and their decomposition in the soil of a reforestation site of Eucalyptus camaldulensis Dehnh, planted more than 50 years ago, and a neighbouring forest dominated by Quercus deserticola Trel. and Q. laeta Liebm (used as reference), in an area of the State of Mexico; and obtain quantitative indicators of the trajectory of rehabilitation through the use of non-native species of Mexico. In reforestation and oak forest, we established 12 sampling sites where the composition, structure and two ecological processes (falling debris and decomposition) were determined. In addition, solar radiation was estimated by taking zenith photos of the canopy, using a hemispherical lens. When data was within normal distribution, we used the Student test, and when it was not, the Wilcoxon test was used to compare the variables studied. The reference forest outperformed reforestation (p ≤ 0.05) in: richness (68 and 50 species); diversity (Simpson index, 1.6-2.6 and 0.7-2.3); normal diameter (21.3 and 13.7 cm), accumulated leaf litter (18.2 and 9.2 Mg ha-1), detritus fall (0.606 and 0.321 Mg ha-1 per month), and litter decomposition (0.443 and 0.251 Mg ha-1 per month). Reforestation had a higher total radiation (5384 vs. 4376 MJ m-2 year-1) and tree height (8.1 vs. 7.4 m). The percentage values of importance were 32.8 and 26.9 % for Quercus deserticola and Q. laeta in the oak forest, and 70 % for E. camaldulensis in the reforestation. After 50 years, reforestation still showed statistical differences from forest in composition, structure, and soil processes. [ABSTRACT FROM AUTHOR]

Fire is one of the most significant agents of disturbance in forest ecosystems, with implications for their structure and composition. An understanding of its dynamics is essential for the delineation of forest management policies in the context of predicted climate scenarios. Based on the monthly monitoring of greenness index (NDVI) values recorded over one year at the individual crown level, this study aimed to analyze the dynamics of NDVI values for four different genera, growing in a Mexican mixed forest and subjected to a prescribed burn, relative to those of a control (unburned) treatment. The results demonstrated the general effect of burning over time on NDVI values among the genera, with Pinus showing the most significant effect, while the effect on Quercus was not significant. Tree height was related to NDVI values for Pinus and Juniperus in the burned area, where low-growing individuals responded negatively in terms of greenness index values. Further studies are still required, but we can conclude that fire plays a differential role in the dynamics of canopy activity and that tree size is an important variable. The results also contribute to our understanding of forest responses to fire disturbance, providing indicators with which to assess ecosystem stability under the threat of extreme climatic variations. [ABSTRACT FROM AUTHOR]

Pinus patula seeds are in high demand for the establishment of plantations in Mexico and around the world because of the fast growth of this species. However, genetically improved germplasm of forest species is scarce in Mexico. For this reason, in 2012, the Mexican government started a program of asexual seed orchards with species of the Pinus genus to meet the germplasm demand. Thus, the objectives of the present research were: to evaluate the height, diameter at breast height, and volume of Pinus patula clones in an asexual seed orchard and to estimate the heritability of these traits. The asexual seed orchard was established in 2012. The diameter at breast height and total height (DBH) were measured and the volume of each ramet was calculated. Subsequently, clonal heritability was estimated for each trait in the four-year-age clones. Differences were found among clones. The average height was 4.38 m, and it varied from 3.39 to 4.80 m for the clones 103 and 28, respectively. The average DBH was 5.46 cm and varied from 3.98 to 6.52 cm for clones 103 and 25, respectively. The average volume was 6.23 dm3 showing a range from 2.62 to 9.53 dm3 for clones 103 and 25, respectively. Clones of Pinus patula had high values of height, DBH, and volume. Heritability values for height, DBH and volume were 0.655, 0.508 and 0.575, respectively. Thus, these traits show high heritability, in other words, they are influenced by genetic component. [ABSTRACT FROM AUTHOR]

Understanding the spatiotemporal links between drought and forest fire occurrence is crucial for improving decision-making in fire management under current and future climatic conditions. We quantified forest fire activity in Mexico using georeferenced fire records for the period of 2005-2015 and examined its spatial and temporal relationships with a multiscalar drought index, the Standardized Precipitation-Evapotranspiration Index (SPEI). A total of 47 975 fire counts were recorded in the 11-year long study period, with the peak in fire frequency occurring in 2011. We identified four fire clusters, i.e., regions where there is a high density of fire records in Mexico using the Getis-Ord G spatial statistic. Then, we examined fire frequency data in the clustered regions and assessed how fire activity related to the SPEI for the entire study period and also for the year 2011. Associations between the SPEI and fire frequency varied across Mexico and fire-SPEI relationships also varied across the months of major fire occurrence and related SPEI temporal scales. In particular, in the two fire clusters located in northern Mexico (Chihuahua, northern Baja California), drier conditions over the previous 5 months triggered fire occurrence. In contrast, we did not observe a significant relationship between drought severity and fire frequency in the central Mexico cluster, which exhibited the highest fire frequency. We also found moderate fire-drought associations in the cluster situated in the tropical southern Chiapas where agriculture activities are the main causes of forest fire occurrence. These results are useful for improving our understanding of the spatiotemporal patterns of fire occurrence as related to drought severity in megadiverse countries hosting many forest types as Mexico. [ABSTRACT FROM AUTHOR]

Background: Critical limb ischemia represents an advanced stage of peripheral arterial disease. Angioplasty improves blood flow to the limb; however, some patients progress irreversibly to lower limb amputation. Few studies have explored the predictive potential of biomarkers during postangioplasty outcomes. Aim: To evaluate the behavior of endothelial progenitor cells in patients with critical limb ischemia, in relation to their postangioplasty outcome. Methods: Twenty patients with critical limb ischemia, candidates for angioplasty, were enrolled. Flow-mediated dilation, as well as endothelial progenitor cells (subpopulations CD45+/CD34+/CD133+/CD184+ and CD45+/CD/34+/KDR[VEGFR-2]+ estimated by flow cytometry) from blood flow close to vascular damage, were evaluated before and after angioplasty. Association with lower limb amputation during a 30-day follow-up was analyzed. Results: Endothelial progenitor cells were related with flow-mediated dilation. A higher number of baseline EPCs CD45+CD34+KDR+, as well as an impaired reactivity of endothelial progenitor cells CD45+CD34+CD133+CD184+ after angioplasty, were observed in cases further undergoing major limb amputation, with a significant discrimination ability and risk (0.75, specificity 0.83 and RR 4.5 p < 0.05). Conclusions: Endothelial progenitor cells were related with endothelial dysfunction, whereas a higher baseline number of the subpopulation CD45+CD34+KDR+, as well as an impaired reactivity of subpopulation CD45+CD34+CD133+CD184+ after angioplasty, showed a predictive ability for major limb amputation in patients with critical limb ischemia. [ABSTRACT FROM AUTHOR]

Introduction: A forest nursery must be provided with abundant water of good quality water. The water with low quality may contain salts, toxic ions, pollutants or diseases. However, in Mexico the quality of water in forest nurseries has received little attention in research. Because of that in this work is performed a diagnosis of the water quality in forest nurseries of Mexico. Method: In 148 containerized forest nurseries ubicated in Mexico, 1 L irrigation water samples were obteined. Such samples were analyzed in the Central laboratory of the Universidad Autónoma Chapingo. From the samples were determined the parameters pH, electric conductivity, concentration of bicarbonates, Ca, B, Mg, sulfates, Na and Cl. With the obtained data was calculated the total hardiness and the adjusted sodium adsorption ratio (this last for nurseries that produce the trees in plastic bags). Results: The parameters that exceded the established limits were: pH (84%, 125 forest nurseries), electric conductivity (34%, 50 forest nurseries), and bicarbonate concentration (77%, 114 nurseries); for the rest of measured parameters, only a small percentage excedes the limit values. From all of the forest nurseries, six that produce in containers and two that produce in plastic bags, fulfill the parameters of quality of water. The rest of nurseries have at least one parameter out of the established limits. Conclusion: Most of the forest nurseries in the temperate region have water with high pH and bicarbonates, while high proportion of those in tropical regions have water with high electric conductivity. It is convenient to choose a good location for the establishment of forest nurseries, in order of having availability of a source of good quality water. [ABSTRACT FROM AUTHOR]

The true prevalence of Chagas disease in Mexico is unknown. However, it has been estimated that 1.1–4 million people are infected with Trypanosoma cruzi , which represents a potential risk for transmission of the disease via contaminated blood. To determine the Chagas disease seroprevalence in donors from eight blood banks in the north of Mexico City, and the northeast of the State of Mexico. Serum samples from blood donors (n = 515,038) were tested to detect the presence of anti- Trypanosoma cruzi antibodies in eight blood banks. The serologic screening test was performed in each of the blood banks. To confirm the seropositive blood donors, only two out of the eight blood banks used a test with a different principle with the aim of identifying anti- Trypanosoma cruzi antibodies. All tests were validated by the Mexican Institute for Epidemiological Diagnosis and Reference. One thousand two hundred and ten blood donors were seropositive for Trypanosoma cruzi , which represents a 0.23% seroprevalence (95% CI 0.22–0.25%). Of the seropositive blood donors, 97.03 % resided in the northeast area of the State of Mexico, Mexico City, and southern part of the State of Hidalgo. Active transmission of Chagas disease may be occurring in non-endemic regions in the northeast of the State of Mexico. [ABSTRACT FROM AUTHOR]

'Vara perlilla' (Symphoricarpos microphyllus H. B. K.) is used to elaborate rustic brooms and Christmas handcrafts. Currently, its natural populations are used and it is cultivated. However, there is a lack of sufficient information regarding species management. With the objective of determining the effects of three levels of fertilization and two clipping heights, this study was carried out in a three-year plantation. The nutritional diagnosis was performed by using the Trends in Concentration method which was used to design a fertilization formula. Nutrients that turned out to be limiting were applied. The experimental design was randomized complete blocks, with six treatments derived from the combination of clipping heights (6 and 12 cm) and fertilization formulas (control, Mn-Zn and NPK+Mn-Zn). The number of resprouts, diameter and length of resprouts, average diameter of resprouts per shrub, average length of resprouts per shrub and aerial biomass were evaluated, before and six months after fertilization. The biomass and the length of resprouts showed an effect from fertilization (p≤0.1), while the clipping height affected the diameter of the shrub and the length of resprouts (p≤0.1). Fertilization of NPK+Mn-Zn with clipping at 6 cm produced the highest stick yield (p≤0.1). Fertilization of 'vara perlilla' (pink snowberry) increases the values of variables of commercial interest. [ABSTRACT FROM AUTHOR]

Forest fires are a cause of global concern, which requires generating knowledge on their spatial behavior. By hypothesizing that the spatial pattern of forest fires across Mexico is randomly distributed, this study aimed at making an analysis of the distribution of forest fires (2005-2015) using remote sensing information and field data collected by CONAFOR (National Forest Commission) and MODIS (Moderate-Resolution Imaging Spectroradiometer). The study compared both sources of information through the G-statistic test that identified clustering patterns. The "hot spots" analysis identified clustered areas with significant values in both data sources. These zones were extended through Sierra Madre Occidental, Península de Yucatán, northern Sierra Madre Oriental and Península de Baja California. The highly coincidental clusters were found in the central-western region along the Eje Neovolcánico, as well as in a small part of Sierra Madre del Sur. The analysis of spatial correlation determined that both sources of information complement each other, enhancing their scope. It is concluded that forest fires in Mexico follow a spatial clustering trend. [ABSTRACT FROM AUTHOR]

Lithological, petromagnetic, paleomagnetic and magnetic fabric studies are employed to determine the flow direction and the location of the source of the, 2.44 to 2.21 Ma, El Castillo ignimbrite in the central-east Mexico. Based on the increasing matrix to pumice ratio and decreasing pumice size, the ignimbrite field is divided into the northwestern, central and south-southeastern sectors. Lithological comparisons among the three sectors reveal that the ignimbrite had flowed from NW to SE, and the source is in the NW part of the study area. Thermomagnetic results concur with the increasing matrix proportions from the proximal to the distal sector. The coercivity and magnetization ratios of the hysteresis parameters are lower in the SE sector than in the NW and central sectors. The dominant flow direction inferred through magnetic fabrics, at most sites, is NW to SE, which coincides with the direction inferred from lithological comparisons. However, at some sites magnetic fabrics demonstrate flow towards ENE or other various directions. The paleomagnetic analysis and field observations reveal that these anomalous directions are a consequence of anticlockwise block rotation and tilting due to normal and lateral faulting in the region. [ABSTRACT FROM AUTHOR]

This article reports single-grain multi-elemental results (Sr, Y, Th, U, and rare earth elements) obtained in 966 apatites from 18 rocks (sandstones and granitoids) that were sampled from the Mesozoic (Todos Santos and San Ricardo Formations) and Eocene (the El Bosque Formation) successions as well as from the Permian–Triassic Chiapas Massif Complex (CMC), all of which are exposed within the Sierra de Chiapas (SCH), SE Mexico. The objectives of the present study are (1) to establish changes in provenance between the Mesozoic and Eocene sedimentary sequences using single-grain apatite geochemistry, and (2) to identify source areas for siliciclastic materials from the Todos Santos, San Ricardo, and the El Bosque Formations. The results of the present work strongly suggest that apatites from the Todos Santos and San Ricardo Formations were mainly derived from intermediate to felsic I-type granitoids as well as from arc-related volcanic rocks, indicating that the CMC basement was the most important source area for the Mesozoic sandstones in the SCH. An abrupt change in provenance from Mesozoic to Eocene units was identified based on single-grain apatite geochemistry. Detrital apatites of the Ypresian–Lutetian El Bosque Formation were derived from diverse source rocks such as mafic–ultramafic rocks, intermediate to felsic I-type plutons, strongly fractionated S-type granites and pegmatites, as well as from different metamorphic source lithologies (including high-pressure rocks) such as gneisses, migmatites, metapelites, and/or eclogites. It was proposed, therefore, that most Eocene sediments of the SCH were derived from the Guatemala Suture Complex, which involves all the rock types mentioned above. A minor portion of the El Bosque Formation sediments was derived from the CMC area and/or from recycled sandstones from the Mesozoic Todos Santos and San Ricardo Formations. Some advantages and disadvantages of provenance studies based on detrital apatite chemistry were also observed and briefly discussed. [ABSTRACT FROM AUTHOR]

Identifying the relative importance of human and environmental drivers on fire occurrence in different regions and scales is critical for a sound fire management. Nevertheless, studies analyzing fire occurrence spatial patterns at multiple scales, covering the regional to national levels at multiple spatial resolutions, both in the fire occurrence drivers and in fire density, are very scarce. Furthermore, there is a scarcity of studies that analyze the spatial stationarity in the relationships of fire occurrence and its drivers at multiple scales. The current study aimed at predicting the spatial patterns of fire occurrence at regional and national levels in Mexico, utilizing geographically weighted regression (GWR) to predict fire density, calculated with two different approaches –regular grid density and kernel density – at spatial resolutions from 5 to 50 km, both in the dependent and in the independent human and environmental candidate variables. A better performance of GWR, both in goodness of fit and residual correlation reduction, was observed for prediction of kernel density as opposed to regular grid density. Our study is, to our best knowledge, the first study utilizing GWR to predict fire kernel density, and the first study to utilize GWR considering multiple scales, both in the dependent and independent variables. GWR models goodness of fit increased with fire kernel density search radius (bandwidths), but saturation in predictive capacity was apparent at 15–20 km for most regions. This suggests that this scale has a good potential for operational use in fire prevention and suppression decision-making as a compromise between predictive capability and spatial detail in fire occurrence predictions. This result might be a consequence of the specific spatial patterns of fire occurrence in Mexico and should be analyzed in future studies replicating this methodology elsewhere. Unlabelled Image • Fire occurrence was predicted with GWR for kernel and regular grid density. • Human factors and aboveground vegetation carbon density influenced fire occurrence. • GWR model accuracy was higher for kernel density compared to regular grid. • Best compromise between model accuracy and spatial detail was obtained at 15–20 km. [ABSTRACT FROM AUTHOR]