Universidad Nacional Autónoma de México
  • Mexico City, Distrito Federal, Mexico
Recent publications
Ocean acidification (OA) has been identified as one of the major climate-change related threats, mainly due to its significant impacts on marine calcifiers. Among those are the calcareous green algae of the genus Halimeda that are known to be major carbonate producers in shallow tropical and subtropical seas. Hence, any negative OA impacts on these organisms may translate into significant declines in regional and global carbonate production. In this study, we compiled the available information regarding Halimeda spp. responses to OA (experimental, in situ), with special focus on the calcification responses, one of the most studied response parameters in this group. Furthermore, among the compiled studies (n = 31), we selected those reporting quantitative data of OA effects on algal net calcification in an attempt to identify potential general patterns of species- and/or regional-specific OA responses and hence, impacts on carbonate production. While obtaining general patterns was largely hampered by the often scarce number of studies on individual species and/or regions, the currently available information indicates species-specific susceptibility to OA, seemingly unrelated to evolutionary lineages (and associated differences in morphology), that is often accompanied by differences in a species’ response across different regions. Thus, for projections of future declines in Halimeda-associated carbonate production, we used available regional reports of species-specific carbonate production in conjunction with experimental OA responses for the respective species and regions. Based on the available information, declines can be expected worldwide, though some regions harbouring more sensitive species might be more impacted than others.
HIV-mediated CNS damage is a result of a combination of direct invasion of the brain by the virus and chronic immune activation leading to in situ cerebral inflammatory reactions. This can manifest clinically as chronic cognitive and/or motor impairment, and given the delicate balance of the CNS milieu, it can result in compartmentalized infection or reservoir establishment, or both. The interactions among the virus, the host immune system, and the cells of the CNS, together with effects on host metabolism, are detailed in this chapter. The implications this has on clinically overt neurological dysfunction and the effects of antiretroviral therapy are also described.
Geometry has impacted human being in different dimensions not only in the creation of meta-objects but also in a deep analysis of them. From this perspective it seems that the object of study focuses on the properties of meta-objects., However it is important to analyze the interaction processes that people carry out for the construction of the geometric space of shape. The process varies on each person depending on their mental models, dominant sensory mechanisms among other factors. In this sense, people that have vision problems do not carry out the same processes in the construction of space compared with people with normal vision. In this sense, the way in which a Weak-Visual (Dv) person interacts with space and with a Work System (WS) like a medium., provides useful information to study the processes of creation and construction of the space on this kind of meta- objects. It was detected from the use of networks that spatial construction of geometric shapes requires different human factors - 2 spatial components, Temporary Interaction Micro-Processes (MPT-I), human interaction cycles, the interrelation of two systems, the interrelation of two typology of meta-representations (MRs), and Focal Attention Processes (PAFs).
Graduation rates and students’ academic trajectories can be used to determine universities’ performance and their response to curricular change. Longitudinal follow-up of students’ academic performance offers “natural experiments” to explore the impact of modified curricula. The goal of this study was to propose a method for analyzing students’ academic trajectories and identify changes associated with a curricular reform. We analyzed students’ trajectories throughout the program in two curricula (1994 and 2010), at the National Autonomous University of Mexico (UNAM) Faculty of Medicine. Advancement of each student was calculated using the accumulated credits in a defined time period, and the percentage of students that completed the credits for each stage of the curriculum. The theoretical framework was the “life course” approach, applying concepts of trajectory, transition and state. R software and TraMineR algorithm were used for data analysis. Five student cohorts of the older curriculum were studied (1994, 1995, 1996, 2004 and 2005 classes), and two cohorts of the new curriculum (2011, 2012), a total population of 6829 students. Students in the newer curriculum had a faster, more timely and efficient advancement in academic pathways, than cohorts in the older one. There was a higher percentage of students with “regular” trajectory (without failed courses) in the newer curriculum. Regularity is a straightforward metric that allows identification of curricular associated changes. This method allows the identification of inflection points throughout students’ academic trajectories, and contrasts pre-post curricular change data.
Understanding public activities and developing thoughtful public health strategies are key goals in efforts to manage the COVID-19 pandemic. This paper explores how seismic noise data can be used as part of such efforts. We show that the fluctuation of seismic noise levels has the capacity to demonstrate aggregate human movement. When considered in relation to major public health efforts, these data can help us evaluate the effectiveness of public health communication strategies that seek to limit social activity. We show evidence that, broadly speaking, Mexican national efforts to encourage “lockdown” worked for a few months in areas around seismic stations, and broke down as time went on. Further, we suggest that changes in the levels of human activity detected in seismic noise can be read alongside social data that provide some clues as to why people respond or not to health recommendations. Our findings have implications for both efforts to understand the nature and effects of public trust in the Mexican state and also the practicalities of using seismic noise data in this manner. An interdisciplinary analysis allows us to address these data and their possible use in a way that takes seriously the opportunities and challenges that emerge in the context of contemporary biopolitics and emerging configurations of surveillance technologies. Analyzing anthropogenic seismic activity opens up new opportunities for ethical data collection and use.
Background Airway obstruction (AO) in asthma is driven by airway smooth muscle (ASM) contraction. AO can be induced extrinsically by direct stimulation of ASM with contractile agonists as histamine, or by indirect provocation with antigens as ovalbumin, while the airway tone is dependent on intrinsic mechanisms. The association of the ASM phenotypes involved in different types of AO and airway tone in guinea pigs was evaluated. Methods Guinea pigs were sensitized to ovalbumin and challenged with antigen. In each challenge, the maximum OA response to ovalbumin was determined, and before the challenges, the tone of the airways. At third challenge, airway responsiveness (AR) to histamine was evaluated and ASM cells from trachea were disaggregated to determinate: (a) by flow cytometry, the percentage of cells that express transforming growth factor-β1 (TGF-β1), interleukin-13 (IL-13) and sarco-endoplasmic Ca ²⁺ ATPase-2b (SERCA2b), (b) by RT-PCR, the SERCA2B gene expression, (c) by ELISA, reduced glutathione (GSH) and, (d) Ca ²⁺ sarcoplasmic reticulum refilling rate by microfluorometry. Control guinea pig group received saline instead ovalbumin. Results Antigenic challenges in sensitized guinea pigs induced indirect AO, AR to histamine and increment in airway tone at third challenge. No relationship was observed between AO induced by antigen and AR to histamine with changes in airway tone. The extent of antigen-induced AO was associated with both, TGF-β1 expression in ASM and AR degree. The magnitude of AR and antigen-induced AO showed an inverse correlation with GSH levels in ASM. The airway tone showed an inverse association with SERCA2b expression. Conclusions Our data suggest that each type of AO and airway tone depends on different ASM phenotypes: direct and indirect AO seems to be sensitive to the level of oxidative stress; indirect obstruction induced by antigen appears to be influenced by the expression of TGF-β1 and the SERCA2b expression level plays a role in the airway tone.
Globally, there is concern about the concentrations of some metals and metalloids in sharks and the associated impacts to themselves and to human consumers. Concentrations of Hg, Cd, and Se reported in muscle, liver and fins of sharks from all the world were reviewed to define geographical patterns of elemental distribution, to model the baseline concentrations of the three elements, and to assess potential human health risk. Published information corresponded to 102 sites that belong to thirteen FAO Major Fishing Areas. The majority of the sites corresponded to the Atlantic (39 sites), followed by the Pacific Ocean (37). Statistical analysis indicated significant differences of elemental concentrations among all FAO regions and oceans. The 5% baseline levels, estimated with a cumulative frequency distribution method for each element were: for Hg, 0.129 μg g−1 in muscle, 0.147 μg g−1 in liver; for Cd, 0.517 μg g−1 in muscle, 0.290 μg g−1 in liver; for Se, 0.105 μg g−1 in muscle, 0.218 μg g−1 in liver. These baseline leves are equivalent to the 5th percentile on a normal distribution. Levels of Cd, Hg and Se in muscle of sharks were above maximum permissible limits (Cd, 0.5; Hg, 1.0; Se, 1.0 μg g−1; Nauen in FAO Fish Circ 764:1–102, 1983; CEC in Off J Eur Union 364:5–24, 2006) for human consumption in 6, 49 and 25% of the reports, respectively. Considering all the studies, hazard quotients (it indicates the risk during the lifetime of an individual different to cancer if value is above one) were Cd (0.10 ± 0.18), Se (0.11 ± 0.10) and Hg (2.05 ± 2.69); i.e. only average Hg values are of concern. The concentrations of Hg and Se in muscle of sharks from the Mediterranean were statistically different from all other oceans. In shark species with more reports, baseline levels (µg g−1 wet weight) of Hg in muscle were: for P. glauca from the Pacific Southeast (0.048), for I. oxyrinchus from the Pacific Southeast (0.034), and for S. lewini from the Pacific Eastern Central (0.55). The balance of Hg and Se molar concentrations (it is used to assess the benefit or risk to the combined occurrence of Hg and Se) in muscle of sharks was assessed through the Se health benefit value (HBVSe), positive results indicate that shark consumption is beneficial to humans. In general, HBVSe was positive (3.06 ± 13.84). According to FAO Fishing areas, negative HBVSe values corresponded to Mediterranean and Black Sea (− 48.37), Atlantic Northwest (− 5.54), Pacific Eastern Central (− 0.97), and Atlantic Southwest (− 0.21); nevertheless, HBVSe values in sharks from Mediterranean and Black Sea, and Atlantic Northwest corresponded to only one species. Overall, similar elemental concentrations were found in some FAO regions of the southern hemisphere. Baseline values of Hg were in the same magnitude order as the low atmospheric deposition flux. Under the approach of the hazard quotient, Hg is of concern because values were above one in almost half of the studies. More information related to Hg and Se in muscle of sharks is required in some FAO regions (Indian Ocean Eastern, Pacific Northeast and Pacific Southeast) to estimate HBVSe.
Background Volcanic eruptions have large effects on forest ecosystems and create new substrates, triggering primary succession processes. The Paricutín volcano, born in central-western Mexico, erupted between 1943 and 1952. After the cessation of the eruptive activity, plant colonization began on the lava flows and tephra deposits, including the conifer species that dominate the surrounding mature forests. This study aims to reconstruct the history of the establishment of conifer trees on the substrates created by the Paricutín eruption. Methods 16 sampling plots were established along three transects with northern, southern, and south-western aspects, located every 250 m from the preserved forest to the volcanic cone. Increment cores from 400 conifer trees were extracted and their age was determined by cross-dating annual tree rings. The order of the species colonization and the tree establishment, abundance, and dominance patterns were characterized. Also, the influence of the distance from the mature forests and the inter-annual climatic conditions on the temporal tree establishment pattern was evaluated. Results Eight pine and one fir species have been established since 1970, only 18 years after the end of the eruptive period. However, tree establishment increased by 12.9% annually after 1995, with the youngest tree in our sample getting established in 2015. We did not find a well-defined temporal and spatial pattern of species arrival, which suggests that colonization occurred randomly, although the four pine species that were established early became the most abundant and dominant. Tree establishment was not influenced by the distance from the mature forest, and wet inter-annual conditions did not enhance pulses of tree recruitment, exhibiting a continuous tree establishment pattern. Conclusions Conifer species have shown a great capacity for colonizing volcanic substrates created by the Paricutín eruption, which suggests that tropical montane conifers can regenerate rapidly under high-magnitude disturbances. These findings support the use of these forest species for ecological restoration.
In 1965 Duwez et al. reported having generated an amorphous, stable phase of palladium-silicon in the region 15 to 23 atomic percent, at.%, silicon. These pioneering efforts have led to the development of solid materials that are now known as Bulk Metallic Glasses, BMG. In 2019 Rodríguez et al. discovered, computationally, that bulk amorphous Pd becomes magnetic, and so does porous/amorphous Pd. Puzzled by these results, the study of several solid binary systems in the Pd-rich zone was undertaken; in particular, the study of the glassy metallic alloy a -Pd $$_{100-c}$$ 100 - c Si $$_{c}$$ c , for $$0 \le c \le 22$$ 0 ≤ c ≤ 22 , ( c in at.%) to see what their topology is, what their electronic properties are and to inquire about their magnetism. In this work it is shown that this metallic glass is in fact magnetic in the region $$0 \le c < 15$$ 0 ≤ c < 15 . Collaterally $$\alpha$$ α and $$\beta$$ β magnetization curves are shown where the net magnetic moment is presented. The topology and the position of the first few peaks of the pair distribution functions, which agrees well with experiment, are also discussed. The BMGs produced experimentally so far are limited in size, but despite this limitation, recent industrial efforts have developed some useful devices that may revolutionize technology.
Corruption has a significant impact on economic growth, democracy, and inequality. It has sever consequences at the human level. Public procurement, where public resources are used to purchase goods or services from the private sector, are particularly susceptible to corrupt practices. However, government turnover may bring significant changes in the way public contracting is done, and thus, in the levels and types of corruption involved in public procurement. In this respect, México lived a historical government transition in 2018, with the new government promising a crackdown on corruption. In this work, we analyze data from more than 1.5 million contracts corresponding from 2013 to 2020, to study to what extent this change of government affected the characteristics of public contracting, and we try to determine whether these changes affect how corruption takes place. To do this, we propose a statistical framework to compare the characteristics of the contracting practices within each administration, separating the contracts in different classes depending on whether or not they were made with companies that have now been identified as being involved in corrupt practices. We find that while the amount of resources spent with companies that turned out to be corrupt has decreased substantially, many of the patterns followed to contract these companies were maintained, and some of those in which changes did occur, are suggestive of a larger risk of corruption.
Background Recruitment after disturbance events depends on many factors including the environmental conditions of the affected area and the vegetation that could potentially grow in such affected areas. To understand the regeneration characteristics that occurs in temperate forests, we evaluated differences in the number of seedlings from trees and shrubs along an altitudinal gradient in Sierra Norte of Oaxaca, Mexico in different biological, climatic, edaphic, light, topographic, and disturbance regimes. Here, we aimed to test the hypothesis that the environmental disturbances influence on recruitment (positive or adverse influence). We sampled the vegetation to obtain recruitment and adult data, and species composition. Results We identified three disturbance regimes: areas affected by forest harvesting, areas exposed to pest management, and undisturbed areas. We identified 29 species of trees and shrubs (9 species of the genus Pinus , 1 species of the genus Abies , 10 species of the genus Quercus, and 9 of other species of broadleaf). We found that both environmental conditions and disturbances influence the recruitment of vegetation in the study area. In particular, disturbances had a positive influence on the regeneration of oak and other broadleaf species by increasing the number of seedlings, and a negative influence on the regeneration of conifers by decreasing the recruitment. Because the recruitment of conifers is more likely in undisturbed areas (sites over 3050 m). Conclusions Environmental factors and anthropogenic disturbances can alter the recruitment of forests. Consequently, knowing which factors are key for the recruitment of vegetation is fundamental for decision-making processes. This is particularly relevant in areas as the one in this study because it provides knowledge to local people on vegetation recovery for a proper management of their biological resources.
Mexico City has one of the highest incidences of acute lymphoblastic leukemia (ALL) globally, with patients showing low survival, and high relapse rates. To gain more insight into the molecular features of B-ALL in Mexican children, we isolated CD10 + /CD19 + precursor B lymphoblasts from four bone marrow and nine peripheral blood samples of B-ALL patients using a fluorescence-activated cell sorting protocol. The global gene expression profile (BM vs PB) revealed 136 differentially expressed genes; 62 were upregulated (45.6%) and 74 were downregulated (54.4%). Pearson’s correlation coefficient was calculated to determine the similarity between pre-B lymphoblast populations. We selected 26 highly significant genes and validated 21 by RT-qPCR ( CNN3, STON2, CALN1, RUNX2, GADD45A, CDC45, CDC20, PLK1, AIDA, HCK, LY86, GPR65, PIK3CG, LILRB2, IL7R, TCL1A, DOCK1, HIST1H3G, PTPN14, CD72, and NT5E ) . The gene set enrichment analysis of the total expression matrix and the ingenuity pathway analysis of the 136 differentially expressed genes showed that the cell cycle was altered in the bone marrow with four overexpressed genes ( PLK1, CDC20, CDC45, and GADD45A ) and a low expression of IL7R and PIK3CG, which are involved in B cell differentiation. A comparative bioinformatics analysis of 15 bone marrow and 10 peripheral blood samples from Hispanic B-ALL patients collected by the TARGET program, corroborated the genes observed, except for PIK3CG . We conclude the Mexican and the Hispanic B-ALL patients studied present common driver alterations and histotype-specific mutations that could facilitate risk stratification and diagnostic accuracy and serve as potential therapeutic targets.
Urban areas serve as melting pots of people with diverse socioeconomic backgrounds, who may not only be segregated but have characteristic mobility patterns in the city. While mobility is driven by individual needs and preferences, the specific choice of venues to visit is usually constrained by the socioeconomic status of people. The complex interplay between people and places they visit, given their personal attributes and homophily leaning, is a key mechanism behind the emergence of socioeconomic stratification patterns ultimately leading to urban segregation at large. Here we investigate mixing patterns of mobility in the twenty largest cities of the United States by coupling individual check-in data from the social location platform Foursquare with census information from the American Community Survey. We find strong signs of stratification indicating that people mostly visit places in their own socioeconomic class, occasionally visiting locations from higher classes. The intensity of this ‘upwards bias’ increases with socioeconomic status and correlates with standard measures of racial residential segregation. Our results suggest an even stronger socioeconomic segregation in individual mobility than one would expect from system-level distributions, shedding further light on uneven mobility mixing patterns in cities.
Background: Hox proteins finely coordinate antero-posterior axis during embryonic development and through their action specific target genes are expressed at the right time and space to determine the embryo body plan. As master transcriptional regulators, Hox proteins recognize DNA through the homeodomain (HD) and interact with a multitude of proteins, including general transcription factors and other cofactors. HD binding specificity increases by protein-protein interactions with a diversity of cofactors that outline the Hox interactome and determine the transcriptional landscape of the selected target genes. All these interactions clearly demonstrate Hox-driven transcriptional regulation, but its precise mechanism remains to be elucidated. Results: Here we report Antennapedia (Antp) Hox protein-protein interaction with the TATA-binding protein (TBP) and the formation of novel trimeric complexes with TFIIEβ and Extradenticle (Exd), as well as its participation in transcriptional regulation. Using Bimolecular Fluorescence Complementation (BiFC), we detected the interaction of Antp-TBP and, in combination with Förster Resonance Energy Transfer (BiFC-FRET), the formation of the trimeric complex with TFIIEβ and Exd in living cells. Mutational analysis showed that Antp interacts with TBP through their N-terminal polyglutamine-stretches. The trimeric complexes of Antp-TBP with TFIIEβ and Exd were validated using different Antp mutations to disrupt the trimeric complexes. Interestingly, the trimeric complex Antp-TBP-TFIIEβ significantly increased the transcriptional activity of Antp, whereas Exd diminished its transactivation. Conclusions: Our findings provide important insights into the Antp interactome with the direct interaction of Antp with TBP and the two new trimeric complexes with TFIIEβ and Exd. These novel interactions open the possibility to analyze promoter function and gene expression to measure transcription factor binding dynamics at target sites throughout the genome.
Transhumant herds graze across two different rangeland types according to the season. Winter rangelands differ from summer rangelands in the amount and quality of available fodder, with the former being the less productive. In cold areas, winter rangeland has low forage quality where goats may suffer severe nutritional restrictions during gestation which lead to significant reproductive losses in the form of abortions and perinatal losses. In Argentinian northern Patagonia, the transhumant Criollo goat is a dual-purpose breed, producing both meat and cashmere and grazing on winter rangelands where they complete their reproductive cycle. Our objective was to evaluate to what extent the winter rangelands of northern Argentine Patagonia satisfy the nutritional requirements needed by Criollo transhumant goats during late gestating. We evaluated a study between 2010 and 2012 where we analysed the body weight and body condition score of the goats reaching the winter rangelands and before kidding. We also analysed the botanical composition of their diet, the quality forage (metabolizable energy, crude protein and digestibility) contribution offered by the species and the proportions of the nutritional requirements of the goats during the last third of gestation. Significantly, we found a decrease in body weight and body condition score in late gestation. In 2010, the goats’ diet showed a nutritional deficiency value of 0.6 Mcal/day metabolizable energy and 30.43 g/day crude protein; in 2011, a deficiency of 0.77 Mcal/day metabolizable energy and 65.48 g/day crude protein; and in 2012, a deficiency of 0.75 Mcal/day metabolizable energy and 55.41 g/day crude protein. Forage present 51, 52 and 48% digestibility in each year, respectively. We conclude that forage quality in winter rangelands in Argentinean Patagonia is not high enough to satisfy the nutritional requirements of Criollo transhumant goats during the last third of gestation. We recommend 550 g/day of an 80:20 mixture of corn:soy expeller supplementation during late gestation.
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44,904 members
Eduardo A Garza Villarreal
  • Institute of Neurobiology
Vijaykumar Yogesh Muley
  • Department of Developmental Neurobiology and Neurophysiology
Julio Augusto Freyre-Gonzalez
  • Centre for Genomic Sciences
Information
Address
Ciudad Universitaria, 04510, Mexico City, Distrito Federal, Mexico
Head of institution
Enrique L. Graue
Website
www.unam.mx
Phone
52 55 56230729