Ecología y fisiología en las primeras fases de crecimiento de plantas suculentas en el sur del desierto chihuahuense en México y las montañas de Córdoba en Argentina.

En esta tesis se presentan dos investigaciones realizadas sobre ecología y fisiología de las primeras etapas de vida de plantas suculentas, la primera en una zona árida mexicana y la segunda en las montañas argentinas. En las zonas áridas, los altos niveles de radiación solar y la escasez de agua son dos factores importantes que limitan el desarrollo de las plántulas. En general, el establecimiento de plántulas suculentas es más exitoso bajo plantas nodriza debido a la sombra proporcionada, ayudando así a reducir el sobrecalentamiento, la transpiración excesiva y la fotoinhibición en plántulas protegidas. La diferencia que un microambiente de una planta nodriza puede proporcionar en el funcionamiento fisiológico de plántulas de suculentas desérticas, podría ser probada midiendo el crecimiento y la fotosíntesis de la planta. En este estudio se midieron las variables relacionadas con la fluorescencia de la clorofila: Rendimiento cuántico efectivo del fotosistema II (ФPSII) y la tasa de transporte de electrones (ETR); así como, la tasa relativa de crecimiento (RGR) y sus componentes (tasa de asimilación neta, NAR, y proporción de área foliar o fotosintética, LAR), proporción raíz/vástago (R/S) y contenido relativo de agua (RWC), para plántulas trasplantadas bajo plantas nodriza y plántulas trasplantadas bajo la luz solar directa. Hemos probado que ФPSII, LAR, proporción R/S y RWC, fueron más bajos, y ETR, RGR y NAR fueron más altos para plántulas de siete especies suculentas comunes al Sur del Desierto Chihuahuense (Agave lechuguilla, A. salmiana, Echinocactus platyacanthus, Ferocactus histrix, Myrtillocactus geometrizans, Stenocactus coptonogonus y Yucca filifera) creciendo bajo la luz directa del sol, en comparación con las trasplantadas bajo árboles nodriza de mezquite. Aunque las especies respondieron de manera diferente a los tratamientos; en general, se encontró que las plántulas creciendo bajo plantas nodrizas tenían alto ФPSII y baja ETR que las que crecían bajo la luz solar directa. RWC, proporción R/S y RGR y sus componentes, variaron en respuesta a los microambientes para algunas especies, pero no de manera consistente. Las variables ecofisiológicas aquí evaluadas fueron más claramente afectadas por la radiación solar que las variables morfológicas. Estos resultados son el primer estudio de campo que incluyen los mecanismos ecofisiológicos y morfológicos de plántulas de especies suculentas bajo plantas nodriza. Las sequías y altas temperaturas podrán aumentar como consecuencia del cambio climático. Esto afectaría la vida de las plantas de diversas maneras, en particular en sus fases iniciales como la germinación y el crecimiento de las plántulas. En especies de crecimiento lento, como los cactus, la germinación de semillas y su establecimiento son las fases más críticas de su ciclo de vida Sin embrago, para que este proceso se pueda llevar a cabo con éxito, se necesita de condiciones favorables Por ello es probable que las especies de cactus de los ecosistemas mésicos sean más afectadas por el cambio climático, que las especies de ecosistemas áridos. El objetivo en este segundo estudio fue evaluar el efecto combinado de potenciales hídricos y temperaturas sobre la germinación de semillas y las características de plántulas en seis especies de cactus globosos de las montañas de Córdoba: Echinopsis candicans, Gymnocalycium bruchii, G. capillaense, G. mostii, G. quehlianum y Parodia mammulosa. Se realizó un experimento factorial en el que se combinaron cuatro niveles de potenciales hídricos (0, -0.2, -0.4 y -0.6 MPa) con dos niveles de temperatura (25 y 32°C). Se registró la germinación (%) y el tiempo medio de germinación (T50); y se midió la forma de la plántula (anchura y longitud). En general, una disminución del potencial hídrico y un aumento de la temperatura dieron como resultado una baja germinación, con diferentes comportamientos entre especies. A 32°C y bajos potenciales hídricos, la germinación fue baja o nula para casi todas las especies. No hubo una clara tendencia en la respuesta de la T50 a los tratamientos. El desarrollo de las plántulas fue altamente y negativamente afectado por la combinación de factores, particularmente en los bajos potenciales hídricos. Las respuestas de las especies de cactus analizadas a bajo potencial hídrico fueron similares a las de especies de cactus de ecosistemas más áridos. Nuestros resultados sugieren que las especies estudiadas se verían gravemente afectadas por los cambios en la temperatura y la precipitación, como se predijo en un escenario de cambio climático. Abstract This thesis shows two researches about ecology and physiology of the first stages of life succulent plants, the first research is in arid Mexican zone and the second is in Argentinean Mountains. In arid zones, the light and water are two important factors that limit the development of seedlings. The shade provided by nurse plants can increase the overheating, excessive transpiration and the photoinhibition in protected seedlings. The difference that a microenvironment of a nurse plant can provide in the physiological functioning of desert succulent seedlings could be tested by measuring the plant growth and photosynthesis. Specifically, in this study we measured the variables related to chlorophyll fluorescence: Effective quantum yield of photosystem II (ΦPSII) and electron transport rate (ETR), as well as relative growth rate (RGR) and its components (net assimilation rate, NAR, and proportion of leaf or photosynthetic area, LAR), root to shoot ratio (R/S) and relative water content (RWC), for seedlings transplanted under nurse plants and seedlings transplanted under direct sunlight. It was proved that ΦPSII, LAR, R/S ratio and RWC were low, and ETR, RGR and NAR were higher for seedlings of seven succulent species common to the Southern Chihuahuan Desert (Agave lechuguilla, A. salmiana, Echinocactus platyacanthus, Ferocactus histrix, Myrtillocactus geometrizans, Stenocactus coptonogonus y Yucca filifera) grown under direct sunlight, in comparison with seedlings transplanted under nurse mezquite trees. Although species responded differently to treatments, in general, it was found that seedlings grown under nurse plants had higher ФPSII and lower ETR than those grown under direct sunlight. The RWC, R/S ratio and RGR and their components varied in response to microenvironments for some species, but not consistently. The echophysiological variables evaluated here were more clearly affected by solar radiation than the morphological variables. These results are the first field study to include the ecophysiological and morphological mechanisms of succulent seedlings under nurse plants. Droughts and high temperatures may increase as a result of climate change. This would affect the life of plants in various ways, particularly in their early stages such as germination and seedling growth. In slow-growing species such as cacti, seed germination and establishment are the most critical phases of their life cycle; However, for this process to be successful, favorable conditions are needed. Therefore, cacti species of mesic ecosystems are more likely to be affected by climate change than arid ecosystem species. The objective of this second study was to evaluate the combined effect of water potentials and temperatures on seed germination and seedling characteristics in six species of globular cactus in the Córdoba Mountains: Echinopsis candicans, Gymnocalycium bruchii, G. capillaense, G. mostii, G. quehlianum y Parodia mammulosa. A factorial experiment was performed in which four levels of water potential (0, -0.2, -0.4 and -0.6 MPa) were combined with two temperature levels (25 y 32°C). Germination (%) and mean germination time (T50) were recorded, and the shape of the seedling (width and length). In general, a decrease in water potential and an increase in temperature resulted in low germination, with different behaviors between species. At 32°C and low water potential, germination was low or zero for almost all species. There was no clear trend in the response of T50 to treatments. Seedling development was highly and negatively affected by the combination of factors, particularly in low water potentials. The responses of cactus species analyzed at low water potential were similar to those of cactus species from more arid ecosystems. Our results suggest that the species studied would be severely affected by changes in temperature and precipitation, as predicted in a climate change scenario

Adaptive Vectorial Filter for Grid Synchronization of Power Converters Under Unbalanced and/or Distorted Grid Conditions

This paper presents a new synchronization scheme for detecting multiple positive-/negative-sequence frequency harmonics in three-phase systems for grid-connected power converters. The proposed technique is called MAVF-FLL because it is based on the use of multiple adaptive vectorial filters (AVFs) working together inside a harmonic decoupling network, resting on a frequency-locked loop (FLL) which makes the system frequency adaptive. The method uses the vectorial properties of the three-phase input signal in the αβ reference frame in order to obtain the different harmonic components. The MAVF-FLL is fully designed and analyzed, addressing the tuning procedure in order to obtain the desired and predefined performance. The proposed algorithm is evaluated by both simulation and experimental results, demonstrating its ability to perform as required for detecting different harmonic components under a highly unbalanced and distorted input grid voltage

Permutation flowshop scheduling problem with total core idle time minimization

-Part of special issue 10th IFAC Conference on Manufacturing Modelling, Management and Control MIM 2022: Nantes, France, 22-24 June 2022 -Copyright © 2022 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)In this paper, we present a deterministic permutation flowshop scheduling problem with a new objective function, the total core idle time. The interest of this objective is related to reduce the energy consumption of the system, taking into account that the energy needed during the processing times is constant, and that machines are switched off during the front and back idle times. Therefore, the energy consumption is dependent on the time where machines are in stand-by mode, i.e during the idle time of machines between jobs, named as core idle times. Constructive heuristics and metaheuristics are adapted from the permutation flowshop scheduling literature for classical objectives as makespan and total completion time. Additionally, a new variant of one of the metaheuristic is proposed, the VBIH-P. An experimental evaluation has been carried out to analyse the performance of all the methods. The results show an excellent performance of the VBIH-P compared to the adapted methods

Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter

Multilevel cascaded H-Bridge converters (CHB) have been presented as a good solution for high power applications. In this way, several control and modulation techniques have been proposed for this power converter topology. In this paper the steady state power balance in the cells of the single phase two cell CHB is studied. The capability to be supplied with active power from the grid or to deliver active power to the grid in each cell is analyzed according to the dc-link voltages and the desired ac output voltage value. Limits of the maximum and minimum input active power for stable operation of the CHB are addressed. Simulation results are shown to validate the presented analysis

Diseño de la red corporativa para la empresa Frigomacz Cia Ltda

En la actualidad las empresas que quieren ser competitivas en cualquier campo de negocio deben estar conectados a la Internet, las comunicaciones con clientes, así como las comunicaciones entre departamentos se han convertido en una parte fundamental de cualquier tipo de empresa, el presente proyecto presenta un estudio para la creación de una red corporativa diseñada para la empresa FRIGOMACZ CIA LTDA, la cual se dedica a la fabricación y venta de productos industriales para panaderías y negocios similares. En este documento se describe como se planeó la creación de una red corporativa tomando en cuenta la dificultad que representa la disposición geográfica de las tres plantas que componen esta empresa, también se analiza el uso y configuración de puntos de acceso a la red de forma inalámbrica, cableado estructurado, el uso e instalación de servicios VoIP, un estudio del beneficio de la inversión que representaría la instalación real de este diseño.Currently companies that want to be competitive in any field of business must be connected to the Internet, communications with clients, as well as communications between departments have become a fundamental part of any type of company, this project presents a study and for the creation of a corporate network designed for the company FRIGOMACZ CIA LTDA, which is dedicated to the manufacture and sale of industrial products for bakeries and similar businesses. This document describes how the creation of a corporate network was planned, taking into account the difficulty represented by the geographical layout of the three plants that make up this company, the use and configuration of wireless network access points is also analyzed, structured cabling, the use and installation of VoIP services, a study of the investment benefit that the actual installation of this design would represent

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.La Lagochilascariasis humana (HL) es producida por Lagochilascaris minor Leiper, 1909; el cual es un parásito que puede ser encontrado también en gatos y perros. HL es considerada una zoonosis emergente en América distribuida desde México hasta Argentina y las islas del Caribe. El presente artículo describe tres casos de HL en la Península de Yucatán, México registrados en la última década. Se describen las características de las lesiones y se discute la ruta de transmisión en humanos y particularmente en los pacientes observados

Growth and ecophysiology of succulent seedlings under the protection of nurse plants in the Southern Chihuahuan Desert

"In arid zones, light and water are two important factors that limit seedling development. The shade provided by nurse plants can reduce overheating, excessive transpiration, and photoinhibition in protege seedlings. The difference that a nurse plant microenvironment may provide on the physiological performance of succulent desert seedlings could be tested by measuring plant growth and photosynthesis. Specifically, in this study we measured the variables related to chlorophyll fluorescence: Quantum yield of photosystem II photochemistry (UPSII) and electron transport rate (ETR), as well as relative growth rate (RGR) and its components (net assimilation rate, NAR, and leaf area rate, LAR), root to shoot (R/S) ratio, and relative water content (RWC) for seedlings transplanted under nurse plants and seedlings transplanted under direct sunlight. We tested whether UPSII, ETR, LAR, R/S ratio, and RWC, were lower, and RGR and NAR were higher for seedlings of seven succulent species common to the Southern Chihuahuan Desert (Agave lechuguilla, A. salmiana, Echinocactus platyacanthus, Ferocactus histrix, Myrtillocactus geometrizans, Stenocactus coptonogonus and Yucca filifera) grown under direct sunlight than for those grown under nurse Mesquite trees. Although species responded differently to treatments, in general we found that seedlings grown under nurse plants had higher UPSII and lower ETR than those grown under direct sunlight. RWC, R/S ratio, and RGR and its components varied in response to microenvironments for some species but not consistently. The ecophysiology variables tested here were more clearly affected by solar radiation than the morphology variables. These results are the first field study including the ecophysiological and morphological mechanisms of seedlings of succulent species under nurse plants.

Germination characteristics of Gymnocalycium monvillei (Cactaceae) along its entire altitudinal range

"Germination characteristics are important for understanding how species cope with environmental variation. The aims of this work were to analyze the effect of different temperatures (25 and 32 °C), water potentials (0, −0.2, −0.4, and −0.6 MPa), and light conditions (light vs. darkness) on the germination of five populations of the cactus Gymnocalycium monvillei (Lem.) Britton & Rose along its entire altitudinal distribution. The experiments to assess the effects of temperature, water potential, and light conditions were performed in germination chambers, and total germination (%) and mean germination time (T50) were recorded. Germination decreased in provenances from higher to lower altitudes, and the effect was very pronounced at temperatures of 32 °C. For all of the altitudinal provenances, germination decreased with lower water potential, with this effect being more pronounced at 32 °C. On the other hand, provenances at lower altitudes were less affected by lower water potentials than higher provenances. Provenances at all altitudes showed very low germination under dark conditions. T50 did not vary among altitudinal provenances at a temperature of 25 °C, but at 32 °C germination was slower at intermediate altitudes. Our results show that germination characteristics differ considerably among altitudinal provenances and seem to be important in determining the capacity of the species to inhabit such a broad gradient.

Are seed mass and seedling size and shape related to altitude? Evidence in Gymnocalycium monvillei (Cactaceae)

"Several studies reported a negative relationship between altitude and seed mass. In cactus species, seed mass has been also related to seedling morphology (size and shape). Here we studied Gymnocalycium monvillei (Lem.) Pfeiff. ex Britton & Rose, a cactus species with a wide altitudinal distribution, with the main aim of analyzing how altitude affects seed mass and seedling size (height and width) and shape (globose or columnar). We collected seeds from five sites along the entire altitudinal distribution of the species in the Córdoba Mountains (sites were located between 878 and 2230 m a.s.l.), encompassing a marked climatic gradient (6 °C of mean annual temperature difference between the extreme sites). Seed mass and seedling traits were measured in the laboratory. Seedling height increased with altitude, whereas seed mass was not related to this parameter. Seedlings became more globose (reduced surface/volume ratio) with decreasing altitude. Variation in seedling shape along the altitudinal gradient may be related to the contrasting climatic conditions to which seedlings are exposed, and could account for the wide altitudinal distribution of G. monvillei. Our results highlight the importance of seedling traits in the species’ response to climatic change.