43 research outputs found
Anatomía radicular, caulinar y foliar en Malpighia mexicana a. Juss. en el Estado de México.
Malpighia mexicana A. Juss., árbol nativo ampliamente distribuido en México, produce bayas ricas en vitamina C y antioxidantes, el fruto representa una alternativa económica, alimenticia y medicinal para los pobladores. El objetivo de este estudio fue comparar las características anatómicas del tallo, hoja y raíz entre individuos de M. mexicana con la finalidad de evaluar su adaptación a ambientes xéricos en tres sitios de recolecta. El estudio se realizó en tres localidades de la faja neovolcánica transversal ubicadas en los estados de México y Morelos. Las muestras se fijaron y prepararon en campo en una solución FAA y se analizaron con base en técnicas convencionales de anatomía vegetal. Se evaluaron 20 variables en hoja, 10 en raíz y 5 para tallo en cortes paradermal, longitudinal y transversal. Los índices de mesomorfía y de vulnerabilidad se estimaron considerando el diámetro de los vasos, el número de vasos/mm2 y la longitud de los elementos de vaso. A los datos obtenidos se les realizó un análisis de varianza o en su caso pruebas no paramétricas y comparación de medias por Tukey (p200 corresponde a xilema mesofitico y el índice de vulnerabilidad >1 sugiere que la especie es resistente al estrés hídrico. El valor más alto del índice de vulnerabilidad corresponde a Morelos con (0.88) y el más bajo al Estado de México con (0.76). La raíz demuestra que la especie es capaz de generar estrategias de adaptación en ambientes xéricos. Este tipo de estudios son importantes para la selección de especies vegetales con fines de restauración ambiental y alimenticia.CONACYT por la beca otorgada (501290) para estudios de posgrado. Se agradece también al Proyecto titulado “Plantas vasculares del estado de México: importancia económica, alimenticia, medicinal y ornamental” apoyado y financiado por el fondo de investigación de la UAEM/3765/2014/CID
The Automated Root Exudate System (ARES): a method to apply solutes at regular intervals to soils in the field.
Root exudation is a key component of nutrient and carbon dynamics in terrestrial ecosystems. Exudation rates vary widely by plant species and environmental conditions, but our understanding of how root exudates affect soil functioning is incomplete, in part because there are few viable methods to manipulate root exudates in situ. To address this, we devised the Automated Root Exudate System (ARES), which simulates increased root exudation by applying small amounts of labile solutes at regular intervals in the field.
The ARES is a gravity-fed drip irrigation system comprising a reservoir bottle connected via a timer to a micro-hose irrigation grid covering c. 1 m2; 24 drip-tips are inserted into the soil to 4-cm depth to apply solutions into the rooting zone. We installed two ARES subplots within existing litter removal and control plots in a temperate deciduous woodland. We applied either an artificial root exudate solution (RE) or a procedural control solution (CP) to each subplot for 1 min day-1 during two growing seasons. To investigate the influence of root exudation on soil carbon dynamics, we measured soil respiration monthly and soil microbial biomass at the end of each growing season.
The ARES applied the solutions at a rate of c. 2 L m-2 week-1 without significantly increasing soil water content. The application of RE solution had a clear effect on soil carbon dynamics, but the response varied by litter treatment. Across two growing seasons, soil respiration was 25% higher in RE compared to CP subplots in the litter removal treatment, but not in the control plots. By contrast, we observed a significant increase in microbial biomass carbon (33%) and nitrogen (26%) in RE subplots in the control litter treatment.
The ARES is an effective, low-cost method to apply experimental solutions directly into the rooting zone in the field. The installation of the systems entails minimal disturbance to the soil and little maintenance is required. Although we used ARES to apply root exudate solution, the method can be used to apply many other treatments involving solute inputs at regular intervals in a wide range of ecosystems
Recruitment limitation in three large‐seeded plant species in a tropical moist forest
Recruitment limitation—the failure of a species to establish recruits at an available site—is a potential determinant of plant communities’ structure, causing local communities to be a limited subset of the regional species pool. Recruitment limitation results from three mechanisms: (i) lack of seed sources (i.e., source limitation), (ii) failure of available seeds to reach recruitment sites (i.e., dispersal limitation), and (iii) failure of arrived seeds to establish at a location (i.e., establishment limitation). Here, we evaluated the relative importance of these mechanisms in three co-occurring tree species (Dipteryx oleifera, Attalea butyracea, and Astrocaryum standleyanum) that share seed dispersers/predators. The study was set up on Barro Colorado Island (Panama) at 62 one-ha sites with varying tree densities. Source limitation was estimated as the proportion of sites that would be reached by seeds if seeds were distributed uniformly. Dispersal limitation was estimated from the number of sites with seeds in the soil bank. Establishment limitation was evaluated by measuring germination and 1-year survival in seed addition experiments. The effect of conspecific and heterospecific densities on the mechanisms was evaluated at three spatial scales (1, 5, and 9 ha). For all species, seed predation was the most important recruitment component (~80% decrease in seed survival). Establishment varied among species and was affected by conspecific and heterospecific species densities across spatial scales. Given that species identity, distribution, and seed dispersal/predation affect recruitment at multiple scales, multiscale studies are required to understand how recruitment limitation determines community structure in tropical forests
Ca2+-induced Ca2+ Release in Chinese Hamster Ovary (CHO) Cells Co-expressing Dihydropyridine and Ryanodine Receptors
VISIONES DE LA EDUCACION FINANCIERA: Analisis y perspectivas.
Este libro es el resultado de un trabajo de investigación por parte de todos
los autores quienes integraron los capítulos, por lo que agradecemos su
confianza e interés para ser parte de este gran proyecto académico.
Gracias a los enlaces de cada una de las Instituciones que aceptaron
respaldar este libro: Marlen Rocío Reyes Hernández, Profesora-Investigadora
de la Universidad Autónoma del Estado de México; Rogelio Valenzuela
Díaz, Decano de la Facultad de Economía de la Universidad de Panamá;
Samuel Alberto Moreno Peralta, Presidente del Colegio de Economistas de
Panamá, a los miembros de la Asociación Mexicana de Especialistas en
Educación Financiera, Asociación Valor México y la Federación de Economistas
de la República Mexicana.
Asimismo, hacemos una deferencia a los jóvenes talentosos que acompañaron
en la coordinación del documento final, entrañables alumnos,
becarios y amigos: Julio César Silva Vázquez y Alfredo Larry Vargas Hernández,
que estamos convencidas que alcanzarán todas sus metas que se
propongan en la vida.
También es necesario reconocer a nuestras amadas familias que compartieron
el tiempo de convivencia, para que lográramos la realización de
este libroVisiones de la educación financiera: análisis y perspectivas es una obra
que enmarca la importancia de la educación financiera en la sociedad
en el contexto actual. Las decisiones que en este tema realiza un individuo
pueden impactar positiva o negativamente su estabilidad económica
por un periodo indeterminado, es aquí cuando la educación financiera
actúa como una herramienta trascendental en su bienestar personal.
Además de tener la función de armadura ante las batallas que se libran
en los mercados —como la crisis financiera de 2008— funge como dinamizador
de las economías al potenciar los proyectos de inversión con el
aumento del emprendedurismo, impactando así en las variables macroeconómicas.
Esta área del conocimiento ha adquirido importancia y popularidad a
nivel internacional a raíz de las crisis económicas de los últimos años, sin
embargo, aún existen, entre otras, brechas sociodemográficas, culturales,
económicas, que no permiten el acceso a estas enseñanzas, excluyendo
parte de la población del proceso del bienestar económico. Para ejemplificar
esta desigualdad, en los capítulos se plasma un panorama internacional
de la educación financiera, considerando las implicaciones y retos
que han tenido las estrategias nacionales de educación financiera a nivel
mundial
Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study
Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak.
Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study.
Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM.
Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide
Legacies of Inequity: How Hometown Political Participation and Land Distribution Shape Migrants’ Paths into Wage Labor
Genetic variability among populations of Triatoma longipennis, vector of Chagas disease in western Mexico
Enzyme polymorphism in Triatoma longipennis Usinger, one of the most important vectors of Chagas disease in Mexico, was analized using starch gel electrophoresis. Seven geographic locations were sampled in order to determine gene flow among populations and to characterize intraspecific differences. Of 18 enzymes assayed, three (ES, MDH, and ME) were successfully resolved and then used to score genetic variation. ES was used to differentiate between populations. Both polymorphism and heterozygosity indicated genetic variability in the populations studied. Gene flow between some populations was found to be high. This finding and the low genetic distance between populations indicate similarity among most of the nearby localities, suggesting an important epidemiological threat
Genetic variability among populations of Triatoma longipennis, vector of Chagas disease in western Mexico
Enzyme polymorphism in Triatoma longipennis Usinger, one of the most important vectors of Chagas disease in Mexico, was analized using starch gel electrophoresis. Seven geographic locations were sampled in order to determine gene flow among populations and to characterize intraspecific differences. Of 18 enzymes assayed, three (ES, MDH, and ME) were successfully resolved and then used to score genetic variation. ES was used to differentiate between populations. Both polymorphism and heterozygosity indicated genetic variability in the populations studied. Gene flow between some populations was found to be high. This finding and the low genetic distance between populations indicate similarity among most of the nearby localities, suggesting an important epidemiological threat
Holocene morpho-stratigraphic evolution of a compound submarine deltaic system in front of the shelf-incising Almanzora and Garrucha Canyons (Palomares margin, southeastern Iberia)
The Holocene morpho-stratigraphic evolution of a compound submarine deltaic system linked with the Antas and Almanzora Rivers on the narrow (< 5 km) shelf along the Palomares margin (southeastern Iberia) has been reconstructed from the integrated analysis of geomorphology, seismo-stratigraphy and sedimentology. The shelf morphology is characterized by a 3–4 km wide deltaic body off the Almanzora River, where seafloor undulations and gullies are present. Larger and more incised gullies, crescent-shaped bedforms and pockmarks are recognizable at or close to the head of shelf-indenting canyons associated with the Almanzora-Garrucha canyon system. The seismo-stratigraphy displays a strong and irregular basal reflector overlain by a sedimentary wedge, showing variable thicknesses (1–25 m) and seismic characteristics along and across the shelf. The main depocenter of this wedge is not located off the Almanzora River mouth (i.e., the main sedimentary input in the study area) but along the southern shelf encompassing the Almanzora and Antas Rivers. Grain-size and sand compositional analyses show that silty sand with high terrigenous content (mostly quartz and mica) is mainly found on the submarine deltaic body. In contrast, sandy silt with variable ratios between terrigenous and biogenic contents is retrieved from the canyon head and associated gullies as well as from the surrounding mid-outer shelf. The evolution of the Antas-Almanzora compound delta has been divided into three evolutionary stages, mainly driven by the interplay between paleo-topography and riverine and marine processes and modulated by sea level changes during the Holocene. The origin of the present-day morphological features is also discussed, again highlighting a complex interaction between sedimentary gravity flows (mainly flash flood-generated hyperpycnal flows), storm-waves and shelf currents, fluid seepage and retrogressive slope failures