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.
Objetivo: avaliar o efeito preliminar da Aprendizagem Baseada em Problemas nas habilidades de Gestão do Cuidado. Método: pré e pós-teste quase experimental, realizado com alunos do curso de Bacharelado em Enfermagem de uma instituição de ensino. A amostra foi composta por 29 (Grupo Experimental) e 74 (Grupo Controle). O Grupo Experimental resolveu quatro cenários sob o método de Aprendizagem Baseada em Problemas com os 7 passos propostos pela McMaster University, em um programa de Gestão do Cuidado na modalidade à distância. O instrumento de autorrelato avaliou as habilidades de Gestão do Cuidado pré e pós-teste em ambos os grupos. Valores médios foram obtidos e estatísticas descritivas e inferenciais foram realizadas (t de Student, t pareado, regressão linear). Resultados: o Grupo Experimental obteve escores mais elevados em habilidades analíticas, de ação e globais do que o Grupo Controle (p<0,05). Não foram registradas diferenças nas habilidades interpessoais ou no uso da informação. O Grupo Controle não apresentou diferenças significativas antes e depois do ensino usual, enquanto as diferenças foram de fato relatadas no Grupo Experimental (p<0,05). Conclusão: apesar de haver poucas evidências sobre o desenvolvimento de habilidades de Gestão do Cuidado de Enfermagem, o presente estudo mostra que a Aprendizagem Baseada em Problemas é um método eficaz e significativo na educação à distância.
Background. Soil microenvironmental variables showed an important key in α and β-tree diversity in Neotropical montane oak forest. Thus, understanding the microenvironment fluctuation at small-fragment effects on tree diversity is crucial in maintaining the montane oak ecosystems. In this study, we hypothesized that within a relatively small-fragment (151.63 ha), tree α and β-diversity fluctuate and specific soil microenvironmental factors could influence tree species diversity to answer three questions: Do tree α and β-diversity differ among transects, even in a short-distance between them? Do microenvironmental variables influence tree diversity composition that occurs within a relict Neotropical montane oak forest? Is there a particular microenvironmental variable influencing tree species-specific? Methods. We established four permanent transects during a year in a relict Neotropical montane oak forest, we assessed tree diversity and specific microenvironmental variables (soil moisture, soil temperature, pH, depth litterfall and light incidence). This allowed us to evaluate how microenvironmental variables at small-fragment influence α and β-tree diversity and tree species-specific. Results. Our results showed that α-diversity was not different among transects; however, β-diversity of tree species was mostly explained by turnover and soil moisture, soil temperature, and light incidence were the microenvironmental variables that triggered the replacement (i.e., one species by another). Those variables also had effect on tree species-specific: Mexican beech (Fagus mexicana), Quebracho (Quercus delgadoana), Pezma (Cyathea fulva), Aguacatillo (Beilschmiedia mexicana), Pezma (Dicksonia sellowiana var. arachneosa), and Mountain magnolia (Magnolia schiedeana). Discussion. Our results confirm our hypothesis related to β-diversity but not with α-diversity; however, the tree community structure of the diversity was similar among transects. Our study represents the first effort to evaluate and link the soil microenvironmental effect on tree α and β-diversity, finding a high replacement in a small-fragment of Neotropical montane oak forest from eastern Mexico.
A partir de un trabajo etnográfico, el artículo analiza las maneras en que una pedagogía comprometida, desarrollada desde hace diez años en una escuela ubicada en los márgenes de la Ciudad de México, echa mano de prácticas artísticas como el performance para ayudar a los estudiantes a indagar y pensar el abandono social que prevalece en sus comunidades, al tiempo que les permite imaginar un futuro más esperanzador. Se propone entender algunos de los performances llevados a cabo como lumpenperformance, pues los alumnos visten harapos y basura para crear imágenes corporales que metaforizan la precarización que se vive en la periferia, revelando posteriormente una imagen que expresa esperanza por medio del acto de “desechar el desecho” con el que finalizan todas estas acciones. Se concluye que los lumpenperformances son procesos pedagógicos de investigación/creación que permiten a los estudiantes articular colectivamente un gesto utópico que no es simple optimismo banal, sino que se manifiesta como una “imaginación material”: un tipo de agencia que configura modos de hacer por medio de la creación de imágenes de desecho que trasmutan en imágenes de esperanza, generando así un aprendizaje sensible y crítico sobre las formas de vida en la periferia urbana.
The current corporate food regime generates some of the most challenging ecological, social, and ethical problems for humanity in its quest for sustainability and ecological justice. Different scientific disciplines have analyzed these problems in-depth, but usually from their comfort zone, i.e., without engagement with other disciplines and epistemologies. The predominance of disciplinary visions seriously limits, however, understanding the complexities of the corporate food regime, including the impacts it generates. Further, most research concerned with this food regime confronts epistemological, methodological, and political limitations to engage with the type of solutions that could lead to transitions to just sustainabilities. Here we review and integrate the findings from scientific literature focused on the ecological, social, or ethical impacts of the corporate food regime, with an emphasis on impacts that operate on a global scale. In addition, we analyze the need for critical science approaches to trigger generative processes for the co-production of uncomfortable, transdisciplinary, actionable knowledges that are fit for designing just and sustainable food regimes. Much of the evidence presented in our analysis is in tension with the interests of the corporate food regime, which fosters decision-making processes based on selective ignorance of the impacts caused by this regime. Our work provides arguments that justify the need to promote transitions to just sustainabilities in agricultural systems from multiple domains (e.g., research and development, public policies, grassroots innovations). We posit that strategies to co-design and build such transitions can emerge from the co-production of uncomfortable, transdisciplinary, actionable knowledges through critical science approaches.
The freeze-thaw (F/T) method is commonly employed during the processing and handling of drug substances to enhance their chemical and physical stability and obtain pharmaceutical applications such as hydrogels, emulsions, and nanosystems (e.g., supramolecular complexes of cyclodextrins and liposomes). Using F/T in manufacturing hydrogels successfully prevents the need for toxic cross-linking agents; moreover, their use promotes a concentrated product and better stability in emulsions. However, the use of F/T in these applications is limited by their characteristics (e.g., porosity, flexibility, swelling capacity, drug loading, and drug release capacity), which depend on the optimization of process conditions and the kind and ratio of polymers, temperature, time, and the number of cycles that involve high physical stress that could change properties associated to quality attributes. Therefore, is necessary the optimization of F/T conditions and variables. The current research regarding F/T is focused on enhancing the formulations, the process, and the use of this method in pharmaceutical, clinical, and biological areas. The present review aims to discuss different studies related to the impact and effects of the F/T process on the physical, mechanical, and chemical properties (porosity, swelling capacity) of diverse pharmaceutical applications with an emphasis on their formulation properties, the method and variables used, as well as challenges and opportunities in developing. Finally, we review the experimental approach for choosing the standard variables studied in the F/T method applying the systematic methodology of quality by design.
Objectives We aim to quantify shifts in hospitalisation and mortality and how those were related to the first three phases of the epidemic and individuals’ demographics and health profile among those with a positive test for SARS-CoV-2 treated at the Mexican Social Security Institute’s facilities from March 2020 to October 2021. Design Retrospective observational study using interrupted time series analysis to identify changes in hospitalisation rate and case fatality rate (CFR) by epidemic wave. Setting Data from the Mexican Institute of Social Security’s (IMSS) Online Influenza Epidemiological Surveillance System (SINOLAVE) that include all individuals that sought care at IMSS facilities all over Mexico. Participants All individuals included in the SINOLAVE with a positive PCR or rapid test for SARS-CoV-2. Primary and secondary outcome measures Monthly test positivity rates, hospitalisation rates, CFRs and prevalence of relevant comorbidities by age group. Results From March 2020 to October 2021, the CFR declined between 1% and 3.5%; the declines were significant for those 0–9, 20–29, 30–39, 40–49 and 70 and older. The decline was steep during the first wave and was less steep or was temporarily reversed at the beginning of the second and third waves (changes in the trend of about 0.3% and 3.8%, and between 0.7% and 3.8%, respectively, for some age groups), but then continued to the end of the analytical period. Prevalence of diabetes, hypertension and obesity among patients testing positive also declined—two for most age groups (reductions of up to 10 percentage points for diabetes, 12 percentage points for hypertension and 19 percentage points for obesity). Conclusion Data suggest that the decrease in COVID-19 fatality rate is at least partially explained by a change in the profile of those contracting the disease, that is, a falling proportion of individuals with comorbidities across all age groups.
Primates are facing an impending extinction crisis. Here, we examine the set of conservation challenges faced by the 100 primate species that inhabit the Brazilian Amazon, the largest remaining area of primary tropical rainforest in the world. The vast majority (86%) of Brazil's Amazonian primate species have declining populations. Primate population decline in Amazonia has been driven principally by deforestation related to the production of forest-risk commodities including soy and cattle ranching, the illegal logging and setting of fires, dam building, road and rail construction, hunting, mining, and the confiscation and conversion of Indigenous Peoples' traditional lands. In a spatial analysis of the Brazilian Amazon, we found that 75% of Indigenous Peoples' lands (IPLs) remained forested compared with 64% of Conservation Units (CUs) and 56% of other lands (OLs). In addition, primate species richness was significantly higher on IPLs than on CUs and OLs. Thus, safeguarding Indigenous Peoples' land rights, systems of knowledge, and human rights is one of the most effective ways to protect Amazonian primates and the conservation value of the ecosystems they inhabit. Intense public and political pressure is required and a global call-to-action is needed to encourage all Amazonian countries, especially Brazil, as well as citizens of consumer nations, to actively commit to changing business as usual, living more sustainably, and doing all they can to protect the Amazon. We end with a set of actions one can take to promote primate conservation in the Brazilian Amazon.
Purpose: We established the most commonly used clinician and patient-reported hip fracture outcome measures as of 2022, assessed their content validity using an International Classification of Functioning, Disability and Health (ICF) framework, and operationalized these results to contribute to an updated hip fracture core set. Materials and methods: A literature search was conducted to identify articles utilizing outcome measures related to hip fracture. A total of five outcome measures were identified, linked to the ICF, and assessed for content validity via bandwidth percent, content density, and content diversity. Results: Outcome measures were linked to 191 ICF codes, most of which were associated with Activities and Participation. Notably, no outcome measure contained concepts linked to Personal Factors and Environmental Factors were underrepresented across all outcome measures. The modified Harris Hip Score had the highest content diversity (0.67), the Hip Disability and Osteoarthritis Outcome Score had the highest bandwidth of ICF content coverage (2.48), and the Oxford Hip Score had the highest content density (2.92). Conclusions: These results clarify the clinical applicability of outcome measures and guide development of hip fracture outcomes that allow providers to assess the complex role of social, environmental, and personal factors in patient rehabilitation.IMPLICATIONS FOR REHABILITATIONHip fracture is a complex and disabling pathology predominantly affecting older adults and represents a public health problem.There are a variety of outcome measures used to assess a patient's recovery following a hip fracture, each with distinctive objectives and modes of administration.Content validity metrics associated with the Harris Hip Score suggest it would be a suitable outcome measure during early-stage recovery, whereas the modified Harris Hip Score may be more suitable for tracking long-term recovery tracking.Choosing an outcome measure most appropriate for a hip fracture patient is an individualized decision that must consider aspects such as age, activity level, needs, and environmental factors.
Understanding patterns of freshwater fish assemblage structure is key to protect them from ongoing human-induced threats to aquatic biodiversity. Yet, studies on associations between fish assemblages and habitat are lacking from many areas of high diversity in Middle America. We assessed fish assemblage structure and environmental associations from a portion of the Lacantún River sub-basin (Usumacinta River, Chiapas, Mexico). Based on environmental data and 17,462 individuals (56 species, 46 genera, and 22 families) captured from 13 sites sampled between 2017-2019, we found that stream order, distance to the Usumacinta, forest cover, temperature, and dissolved oxygen are key to explaining assemblage composition. Four clusters were found via multivariate regression tree analysis, with stream order and dissolved oxygen as defining variables. Our findings suggest that fish communities remain spatially structured even at small scales, in association to environmental gradients among habitats.
Estradiol and progesterone have been recognized as important mediators of reproductive events in the female mainly via binding to their receptors. This study aimed to characterize the immunolocalization of the estrogen receptor alfa (ERα), estrogen receptor beta (ERβ) and progesterone receptor (PR) in the ovarian follicles of the lizard Sceloporus torquatus. The localization of steroid receptors has a spatio-temporal pattern that depends on the stage of follicular development. The immunostaining intensity of the three receptors was high in the pyriform cells and the cortex of the oocyte of previtellogenic follicles. During the vitellogenic phase, the granulosa and theca immunostaining was intense even with the modification of the follicular layer. In the preovulatory follicles, the receptors were found in yolk and additionally, ERα was also located in the theca. These observations suggest a role for sex steroids in regulating follicular development in lizards, like other vertebrates.
Given a compact Riemann surface X of genus at least 2 with automorphism group G, we provide formulae that enable us to compute traces of automorphisms of X on the space of global sections of G-linearized line bundles defined on certain blow-ups of projective spaces along the curve X. The method is an adaptation of one used by Thaddeus to compute the dimensions of those spaces. In particular, we can compute the traces of automorphisms of X on the Verlinde spaces corresponding to the moduli space SUX(2,ξ)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$SU_{X}(2,\xi )$$\end{document} when ξ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\xi $$\end{document} is a line bundle G-linearized of suitable degree.
Bunodeopsis pelagica is one of the few species of sea anemones known to be found in the floating algae of Sargassum spp. It has been reported in the North Atlantic, particularly in the Canary Islands and the coast of Jamaica. The present study is the first to report the occurrence of B. pelagica in the Mexican Atlantic, found as epiphyte on Sargassum natans off Alacranes reef (southern Gulf of Mexico) and in Puerto Morelos reef (Mexican Caribbean), revealing that this species is much more widespread than has been reported. Bunodeopsis pelagica is mainly distinguished from other species of Bunodeopsis by having simple minute protuberances on its column, while its congeners have larger and much more developed vesicular projections. With the record of B. pelagica , the number of known species of actiniarian sea anemones from the Mexican Atlantic increases to 23.
Partial hedging of American options is an interesting minimax problem and in this paper we establish its dual problem that concerns only maximization. The case of a continuous price process is considered under a general incomplete market. Our construction of a duality requires a careful preparation in order to define the dual domain with a compactness property. A key step is an extension of linear functionals preserving norm and positivity.
More than half of Mexico’s forests and about a third of the forests of the world are communally-owned. Despite this, community forest management (CFM) is the least studied forest management policy, and existing studies have focused on the effects of CFM on deforestation. In this paper, we evaluate the effect of CFM on land cover more broadly, to understand how CFM affects a community’s land use decisions. . Mexico’s forestry administration mandates that to legally sell timber, communities must adopt forest management plans designed by a certified forester. In this study, we use differential access to foresters to identify the effect of community management on land cover and deforestation. We find that over time communities that adopt management plans see relatively more primary forest, a limited expansion of the agricultural frontier, and a decrease in deforestation. The decrease in deforestation is economically significant since the economic benefits from the avoided CO2 emissions alone could far outweigh the costs of adopting the management plans.
This study explores recovery from severe mental disorders from the perspective of 89 mental health care professionals working in Mexico City, using a mixed method approach. The participants were recruited and interviewed from mental health and addiction treatment facilities in Mexico City using convenience sampling techniques. Transcribed interviews were coded and analyzed for thematic content regarding recovery and relapse of mental illness. On the quantitative level, we used a sample of 11 items from the Mexican adaptation of the Opinions about Mental Illness questionnaire to compare the attitudes of health personnel and consider differences by gender. Of the respondents, 18% did not believe that recovery was possible for individuals with severe mental disorders, but most believed in recovery in at least some cases. The results also indicated a strong orientation toward recovery in the clinical sense, focused on patients’ symptomatology. There were significant differences in attitudes toward mental illness items by gender. Men showed more favorable attitudes than women (F = 6.60, p = .05). However, the small size of our sample limits the generalizability of the findings. Educational strategies based on social contact with persons with mental health problems could be useful in modifying negative attitudes toward mental illness.
Background The main objective of this research was to analyze the characteristics of electrical activity in the brain during REM (Rapid Eye Movements) sleep, by using an experimental model a pathology that affects the frontal lobes, such as brain tumors. In addition to determining the impact of variables such as the frontal area (dorsolateral, medial and orbital), laterality and size of the lesion; as well as the demographic and clinical characteristics of the patients evaluated. Methods By using polysomnographic recordings, 10 patients were evaluated. We obtained power spectra through a homemade program. For quantitative EEG (Electroencephalogram) (qEEG) analysis, the Fast Fourier Transform (FFT) algorithm was used to obtain the spectral power of each participant, channel, and frequency band. Results Sleep architecture and spectral power was found to be modified in patients compared to normative values. Other sociodemographic and clinical characteristics of the patients were also influenced, such as age range and antiepileptic drugs. Conclusions Brain tumors in the frontal lobe can modify the rhythmogenesis of REM sleep, possibly due to changes of brain plasticity as an effect of the pathology. In addition to this, through this study we were able to show the association between neuroanatomical and functional changes, on the characteristics of brain electrical activity in patients with frontal brain tumor. Finally, this qEEG analysis technique allows, on the one hand, to deepen the knowledge and relationship between psychophysiological processes and, on the other hand, to be able to guide therapeutic decisions.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
47,540 members
Eduardo A Garza Villarreal
  • Institute of Neurobiology
Julio Augusto Freyre-Gonzalez
  • Centre for Genomic Sciences
Ciudad Universitaria, 04510, Mexico City, Distrito Federal, Mexico
Head of institution
Enrique L. Graue
52 55 56230729