Listado de angiospermas epífitas que conforman jardines de hormigas de Azteca gnava (Formicidae) en el sureste de México

Background and Aims: The humid tropical forest canopy hosts a great diversity of epiphytic plants and arboreal ants. These biological groups are usually studied individually without considering their interactions. Still, they can establish complex and specialized mutualisms such as ant-gardens, a particular assembly of epiphytic angiosperms cultivated by ants. This work aimed to present the first annotated checklist and the distribution maps of the epiphytes and one ant species associated with ant-gardens in southeastern Mexico. Methods: We compiled occurrence records of the angiosperm epiphytes and ant species in specialized literature, herbarium records and photographs in national and international online databases, as well as field observations. Key results: We reported a total of eight species of epiphytes belonging to six angiosperm families and the ant Azteca gnava, distributed in southeastern Mexico (Veracruz to Quintana Roo) and with the highest diversity on the border between the states of Tabasco and Chiapas. Epidendrum flexuosum was the most representative species of the ant-gardens in southeastern Mexico. Conclusions: The ant-gardens are complex systems, and their study in Mexico is incipient, so we hope this work will encourage their research and the conservation of canopy species and their mutualisms.Antecedentes y Objetivos: El dosel de las selvas húmedas alberga una gran diversidad de plantas epífitas y hormigas arborícolas. Estos grupos biológicos suelen ser estudiados individualmente sin considerar sus interacciones, pero pueden establecer mutualismos complejos y especializados como los jardines de hormigas, los cuales son un ensamble particular de angiospermas epífitas cultivadas por hormigas. El objetivo de este trabajo fue presentar el primer listado comentado y los mapas de distribución de las epífitas y una especie de hormiga que se asocian en jardines de hormigas reportados en el sureste de México.Métodos: Se recopilaron registros de ocurrencia de las especies de angiospermas epífitas y hormigas en la literatura especializada, registros de herbario y fotografías disponibles en bases de datos en línea nacionales e internacionales, así como observaciones en campo. Resultados clave: Un total de ocho especies de epífitas pertenecientes a seis familias de angiospermas y la hormiga Azteca gnava, fueron documentados en el sureste de México (de Veracruz a Quintana Roo), siendo los límites entre los estados de Tabasco y Chiapas en donde se concentra la mayor diversidad. Epidendrum flexuosum fue la especie más representativa de los jardines de hormigas en el sureste de México.Conclusiones: Los jardines de hormigas son sistemas complejos y su estudio en México es incipiente, por lo que se espera que este trabajo incentive tanto el estudio como la conservación de las especies del dosel y sus mutualismos

5to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

El V Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2019, realizado del 6 al 8 de febrero de 2019 y organizado por la Universidad Politécnica Salesiana, ofreció a la comunidad académica nacional e internacional una plataforma de comunicación unificada, dirigida a cubrir los problemas teóricos y prácticos de mayor impacto en la sociedad moderna desde la ingeniería. En esta edición, dedicada a los 25 años de vida de la UPS, los ejes temáticos estuvieron relacionados con la aplicación de la ciencia, el desarrollo tecnológico y la innovación en cinco pilares fundamentales de nuestra sociedad: la industria, la movilidad, la sostenibilidad ambiental, la información y las telecomunicaciones. El comité científico estuvo conformado formado por 48 investigadores procedentes de diez países: España, Reino Unido, Italia, Bélgica, México, Venezuela, Colombia, Brasil, Estados Unidos y Ecuador. Fueron recibidas un centenar de contribuciones, de las cuales 39 fueron aprobadas en forma de ponencias y 15 en formato poster. Estas contribuciones fueron presentadas de forma oral ante toda la comunidad académica que se dio cita en el Congreso, quienes desde el aula magna, el auditorio y la sala de usos múltiples de la Universidad Politécnica Salesiana, cumplieron respetuosamente la responsabilidad de representar a toda la sociedad en la revisión, aceptación y validación del conocimiento nuevo que fue presentado en cada exposición por los investigadores. Paralelo a las sesiones técnicas, el Congreso contó con espacios de presentación de posters científicos y cinco workshops en temáticas de vanguardia que cautivaron la atención de nuestros docentes y estudiantes. También en el marco del evento se impartieron un total de ocho conferencias magistrales en temas tan actuales como la gestión del conocimiento en la universidad-ecosistema, los retos y oportunidades de la industria 4.0, los avances de la investigación básica y aplicada en mecatrónica para el estudio de robots de nueva generación, la optimización en ingeniería con técnicas multi-objetivo, el desarrollo de las redes avanzadas en Latinoamérica y los mundos, la contaminación del aire debido al tránsito vehicular, el radón y los riesgos que representa este gas radiactivo para la salud humana, entre otros

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Modularity and robustness of a plant-frugivore interaction network in a disturbed tropical forest

<p>Tropical forests are undergoing a biodiversity crisis including defaunation processes. Structure and function of biotic communities in disturbed ecosystems can be assessed with network analyses of interspecific interactions. In a disturbed tropical forest we studied the network of interactions between fruiting plants and three groups of frugivorous animals, determining the structure, modular roles of species and the robustness of the network under simulated extinction scenarios based on species strength (SS) (relevance), species role (SR) (connectivity) and body size (vulnerability). We recorded 5,347 interactions between 63 frugivore and 60 plant species. The network had a modular structure with four modules: (1) plants with exposed fruits consumed by bats; (2) plants with juicy fruits consumed by larger birds; (3) plants with dry high-lipid-content fruits consumed by migratory birds; and (4) generalist plants consumed by several frugivores (three guilds). Robustness of the network was lower when species with high SS or important connectivity roles (i.e., module hubs) were lost first; when larger animals were lost first the network was more robust than in the other scenarios. Our results suggest that modularity may protect disturbed communities against species loss. We provide bases for developing ecologically-sound measures for the conservation of ecological interactions in anthropogenic landscapes.</p

The effect of tropical dry forest seasonality on the diversity of insects associated with ferns

Abstract Seasonality is one of the main characteristics of a tropical dry forest that affects the structure of ecological communities. In this context, we evaluated the seasonal diversity of ferns and insects in the tropical dry forest of Morelos, Mexico, to determine whether a relationship exists between the presence of each of these two groups. Hill’s numbers indicated differences in the diversity of both groups according to season. In the rainy season, we recorded the highest diversity of ferns, with 6,471 individuals. In contrast, in the dry season, we recorded only 293 individuals. Regarding the insects, we collected 723 individuals in the rainy season and 171 individuals in the dry season. The order Orthoptera was the most abundant (50%). The best-represented functional group according to feeding guild was that of chewing herbivores. Correlation analysis revealed a positive relationship between insect and fern abundances since, for both groups, the minimum abundance was presented in the dry season and the maximum abundance in the rainy season. We recorded 12 orders of insects associated with eight ferns in the rainy season. Seasonal studies that consider different biological groups are necessary to understand how changes in resource availability shape temporal patterns of species diversity

Spatio-temporal variation of Cerambycidae-host tree interaction networks.

Despite its high ecological importance, the commensal interactions at community level are poorly studied. In tropical dry forests (TDF) there is a great diversity of species adapted to the high seasonality that characterizes them; however, little is known regarding how the spatial and temporal availability of resources generates changes in the pattern of commensal interactions. We experimentally studied changes in the diversity, composition, and pattern of interactions in spatio-temporal associations between the saproxylophagous beetles and their host trees in a TDF in Morelos, Mexico. A total of 65 host tree species were selected, from which 16 wood sections were obtained per species. These sections were exposed in the field to allow oviposition by the cerambycids under four different (spatio-temporal) treatments. We analyzed the network structure and generated indices at species level (i.e., specialization, species strength, and effective partners) and those related to physical characteristics of the wood (hardness and degradation rate) and the cerambycids (body size). In total, 1,323 individuals of 57 species of cerambycids emerged. Our results showed that, independently of the space and time, the network presented a nested and modular structure, with a high specialization degree and a high turnover of cerambycid species and their interactions. In general, we found that the cerambycids are mostly associated with softwood species with a lower decomposition rate of wood, as well as with the most abundant host species. The commensalistic interactions between the cerambycids and their host trees are highly specialized but are not spatio-temporally static. The high turnover in the interactions is caused by the emergence patterns of cerambycids, which seem to restrict their use to certain species. The knowledge of the spatio-temporal variation in Cerambycidae-host tree interactions allows us to predict how environmental and structural changes in the habitat can modify the species ensemble, and therefore its interactions