Registros recientes de Avicennia bicolor (Acanthaceae) en la costa del Pacífico mexicano con notas sobre su distribución y estado de conservación

Background. The mangrove Avicennia bicolor was first recorded in Mexico in 1946, however until now there is no basic information about its distribution supported by herbarium specimens. Goals. Three recent records of A. bicolor are provided at a new location in Mexico on the coastal wetlands of the Gulf of Tehuantepec, Chiapas; and the information about its known records on the American Pacific is summarized. Methods. Plant specimens were collected, which then, were dried, corroborated and deposited in four national herbaria. In the field, some structural attributes of the mangroves were determined such as density, basal area and height. A database and publications of species records were reviewed to preliminarily analyze their known distribution in the Pacific. Results. In Mexico, A. bicolor has been recorded only on the coastal wetlands of Mar Muerto and Los Patos-Solo Dios. The preliminary ecological diagnosis showed its presence in relatively dense stands (234 ± 86 trees ha-1) and with high structural development (basal area: 16.1 m2 ha-1, height: 13.9 m). Although its presence is apparently conspicuous in several localities of Panama and Costa Rica, data on the species in the coastal strip between the Gulf of Fonseca and the Gulf of Tehuantepec is lacking. Conclusions. The importance of these records is evident, considering the scarce information available on A. bicolor and its restricted distribution in Mexico. We consider it appropriate to increase the ecological studies in its distribution area and give it protection through its inclusion in the Official Mexican Standard (NOM-059).Antecedentes. El mangle Avicennia bicolor fue registrado por primera vez en México en 1946, sin embargo, hasta ahora se carece de información básica sobre su distribución respaldada en ejemplares de herbario. Objetivos. Aportar tres registros recientes de A. bicolor en una nueva localidad para México en humedales costeros del Golfo de Tehuantepec, Chiapas y resumir la información sobre sus registros conocidos en el Pacífico americano. Métodos. Se recolectaron ejemplares botánicos, los cuales fueron herborizados, corroborados y depositados en cuatro herbarios nacionales. En campo se determinaron algunos atributos estructurales de los manglares (densidad, área basal, altura). Se revisó una base de datos y publicaciones de registros de la especie para analizar preliminarmente su distribución conocida en el Pacífico. Resultados. En México, A. bicolor se ha registrado únicamente en los humedales costeros de Mar Muerto y Los Patos-Solo Dios. El diagnóstico ecológico preliminar demostró su presencia en rodales relativamente densos (234±86 árboles ha-1) y con elevado desarrollo estructural (área basal: 16.1 m2 ha-1; altura: 13.9 m). Aunque su presencia es apa rentemente conspicua en varias localidades de Panamá y Costa Rica, se carece de datos sobre la especie en la franja costera comprendida entre el Golfo de Fonseca y el Golfo de Tehuantepec. Conclusiones. Se evidencia la importancia de estos registros, considerando la escasa información disponible y su restringida distribución en México. Consideramos congruente incrementar los estudios ecológicos en su área de distribución y darle protección mediante su inclusión en la Norma Oficial Mexicana (NOM-059)

Temporal coincidence of the annual eelgrass Zostera marina and juvenile scallops Argopecten ventricosus (Sowerby II, 1842) in Bahía Concepción, Mexico

Temporal coincidence of the annual eelgrass Zostera marina and juvenile scallops Argopecten ventricosus (Sowerby II, 1842) in Bahia Concepcion, Mexico

Análisis de la afectación térmica y esfuerzos generados por soldadura en carrocerías de autobuses

Introduction: In Ecuador in recent years there have been various traffic accidents in which interprovincial buses are involved due to numerous factors that produced these accidents that cause human losses and material damages. Objective: The objective of this work is to analyze the quality and safety of the occupants when they are transferred from one place to another, through the study of the thermal affectation in the microstructure of the material during the welding process. Methodology: The work methodology consists of analyzing the microstructure of welded ASTM A-500 steel specimens through SMAW and GMAW processes and considering standard welding parameters that are used in the country's bodywork industries. For the analysis, the front part of the bus has been considered due to the importance of the loads on this element, the union of the specimens was developed by means of a butt joint and the analysis of thermal stresses in the material was executed in the Ansys software. Results: The microstructural analysis of the specimens before and after the welding processes show the presence of pearlite and ferrite mostly without changes in the morphology of the material, from the thermal analysis it is determined that the GMAW process presents a higher index of thermal conductivity with a value of 0,9255W/ and the maximum deformation that the material presents is 0.17167 mm. Conclusions: Under the parameters analyzed, since there are no changes in the microstructure, it is concluded that a heat treatment is not necessary before or after the welding processes, therefore the mechanical properties of the material are not affected. From thermal analysis it is determined that the zone of influence of heat is approximately 1.5-2mm.Introducción: En el Ecuador durante los últimos años se han presentado diversos accidentes de tránsito en lo que están involucrados los buses interprovinciales por numerosos factores que produjeron dichos accidentes que producen pérdidas humanas y afectaciones materiales. Objetivo: el objetivo de este trabajo es analizar la calidad y la seguridad de los ocupantes al momento de ser trasladados de un lugar a otro, por medio del estudio de la afectación térmica en la microestructura del material durante el proceso de soldadura. Metodología: La metodología de trabajo consiste en analizar la microestructura de probetas soldadas de acero ASTM A-500 mediante procesos SMAW y GMAW y considerando parámetros normados de soldadura que se usan en las industrias carroceras del país. Para el análisis se ha tomado en cuenta la parte frontal del autobús debido a la importancia de las cargas sobre este elemento, la unión de las probetas se desarrolló mediante junta a tope y el análisis de esfuerzos térmicos en el material se ejecutó en el software Ansys. Resultados: El análisis microestructural de las probetas antes y después de los procesos de soldeo muestran la presencia de perlita y ferrita mayoritariamente sin cambios en la morfología del material, del análisis térmico se determina que el proceso GMAW presenta un mayor índice de conductividad térmica con un valor de 0,9255W/ y la deformación máxima que presenta el material es de 0,17167 mm. Conclusiones: Bajo los parámetros analizados, al no existir cambios en la microestructura se concluye que no es necesario un tratamiento térmico antes o después de los procesos de soldadura por lo tanto las propiedades mecánicas del material no se ven afectadas. Del análisis térmico se determina que la zona de influencia de calor es de aproximadamente 1,5-2mm. Área de estudio general: Ingeniería Automotriz. Área de estudio específica: Soldadura

Regional Genetic Structure in the Aquatic Macrophyte Ruppia cirrhosa Suggests Dispersal by Waterbirds

The evolutionary history of the genus Ruppia has been shaped by hybridization, polyploidisation and vicariance that have resulted in a problematic taxonomy. Recent studies provided insight into species circumscription, organelle takeover by hybridization, and revealed the importance of verifying species identification to avoid distorting effects of mixing different species, when estimating population connectivity. In the present study, we use microsatellite markers to determine population diversity and connectivity patterns in Ruppia cirrhosa including two spatial scales: (1) from the Atlantic Iberian coastline in Portugal to the Siculo-Tunisian Strait in Sicily and (2) within the Iberian Peninsula comprising the Atlantic-Mediterranean transition. The higher diversity in the Mediterranean Sea suggests that populations have had longer persistence there, suggesting a possible origin and/or refugial area for the species. The high genotypic diversities highlight the importance of sexual reproduction for survival and maintenance of populations. Results revealed a regional population structure matching a continent-island model, with strong genetic isolation and low gene flow between populations. This population structure could be maintained by waterbirds, acting as occasional dispersal vectors. This information elucidates ecological strategies of brackish plant species in coastal lagoons, suggesting mechanisms used by this species to colonize new isolated habitats and dominate brackish aquatic macrophyte systems, yet maintaining strong genetic structure suggestive of very low dispersal.Fundacao para a Cincia e Tecnologia (FCT, Portugal) [PTDC/MAR/119363/2010, BIODIVERSA/0004/2015, UID/Multi/04326/2013]Pew FoundationSENECA FoundationMurcia Government, Spain [11881/PI/09]FCT Investigator Programme-Career Development [IF/00998/2014]Spanish Ministry of Education [AP2008-01209]European Community [00399/2012]info:eu-repo/semantics/publishedVersio

El proyecto de Constitución de Chile: aportes al debate desde Ecuador

En la presente obra varios docentes del Área de Derecho de la Universidad Andina Simón Bolívar-Sede Ecuador, desde distintas perspectivas y disciplinas jurídicas, analizan doctrinaria y críticamente el proyecto de Constitución de Chile. Estas miradas fueron expuestas en un seminario público, realizado en Quito, el 14 de julio de 2022, en la Universidad Andina Simón Bolívar-Sede Ecuador. Este libro está dividido en tres partes. Una primera introductoria, en la que se hace un análisis general al proyecto. En la segunda agrupación de ensayos, se encuentra el análisis de la teoría de los derechos, algunos derechos específicos y las garantías. Finalmente, en la tercera parte encontramos el análisis de algunos aspectos sobre la organización del Estado y la reforma constitucional

Ciclo de crecimiento y fenología de la fanerogama Zostera marina L. en Punta Arena, Bahía Concepción, B.C.S. México.

Impreso y PD

Phenology and growth cycle of annual subtidal eelgrass in a subtropical locality

This study describes the phenology, life cycle and reproductive potential of Zostera marina L. (eelgrass) in Bahı́a Concepción, the southernmost population on the west coast of the Gulf of California. Z. marina populations in the Gulf of California are the unique annual subtidal meadows existing only in the coldest season of the year, from December to May, and surviving the adversely warm summer season as seeds. The maximum shoot density was 2334 shoots per square meter in January, the minimum recorded during the growth season was 664 shoots per square meter in May. Before December and after May no living plants were found. Until March, the percentage cover of the meadow was up to 90%, in April some patches of dead shoots were found (16%) and in May the meadow disappeared. Several growth variables, such as above-ground biomass, rhizome branching, leaf-blade morphology, and leaf area index, showed that the main vegetative growth was in the period December–January. The appearance of the first flowering shoots was in late January and the first fruit appearance was observed in March. The presence of flowers was observed from February to May. Fruit production was maximum in late March (21 fruits per shoot), decreasing later to eight fruits per shoot due to the release of seeds. Seed production was estimated to be 30,000 seeds per square meter