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GENERATION OF LG VECTOR MODES WITH ULTRAHIGH STABILITY BASED ON COMPLEX AMPLITUDE MODULATION IN AN ON-AXIS CONFIGURATION

Gloria Elizabth Rodríguez García (2023, [Tesis de maestría])

"This thesis presents a novel technique for generating vector beams using complex amplitude modulation (CAM) in an on-axis configuration. The holograms used to generate the beams were created using the Mathlab software and displayed on a reflective spatial light modulator (SLM). The main goal of this research was to address both the purity and stability of the beams during generation and propagation, introducing a quantitative approach to assess their stability. As a proof-of-concept, Laguerre-Gaussian vector beams have been generated and characterized using Stokes polarimetry with the proposed experimental set up."

Structured light Laguerre-Gauss vector beams Stokes polarimetry Beam generation Spatial light modulators CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA OPTICA FÍSICA OPTICA FÍSICA

Ecología trófica del pez damisela Stegastes acapulcoensis (Pomacentridae) en un arrecife de Bahías de Huatulco, Oaxaca

Trophic ecology of the damselfish Stegastes acapulcoensis (Pomacentridae) in a reef of Bahías de Huatulco, Oaxaca

Diana Alejandra Vela Espinosa (2023, [Tesis de maestría])

Se caracterizó la alimentación y la morfología del sistema alimentario de la damisela Stegastes acapulcoensis en la bahía La Entrega, Oaxaca, con el objetivo de determinar su espectro trófico. En agosto de 2022, se recolectaron 30 ejemplares de S. acapulcoensis en el período de mayor actividad de alimentación, utilizando arpones caseros y equipo de buceo SCUBA. Las muestras se fijaron con formol al 5% para preservar sus tejidos y facilitar la identificación de presas. Cada ejemplar se sometió a un análisis biométrico detallado, incluyendo mediciones de peso total, longitud total y longitud estándar. Los componentes alimentarios se identificaron y clasificaron en nueve categorías, con las algas destacando como el componente más consumido, seguido del detritus y los invertebrados. El Índice de Importancia Relativa (%IIR) confirmó la importancia de estos componentes en la dieta de S. acapulcoensis. El análisis del espectro trófico reveló que esta especie es un depredador generalista, con una dieta que abarca una diversidad moderada de componentes alimentarios. Además, se encontró una correlación positiva significativa entre el peso de los individuos y su consumo de algas, lo que sugiere una relación entre el tamaño y los hábitos alimentarios. La morfología del sistema alimentario, incluyendo el aparato mandibular y las placas faríngeas, apoyó la adaptación de S. acapulcoensis a una dieta herbívora oportunista. Los dientes incisivos y las características de las placas faríngeas indicaron una especialización en la captura y procesamiento de alimentos vegetales. En conjunto, estos hallazgos proporcionaron una visión completa de la ecología alimentaria de S. acapulcoensis en La Entrega, resaltando la importancia de las algas en su dieta y su capacidad para ajustarse a diferentes fuentes de alimento. Además, se amplió nuestra comprensión de la relación entre la morfología y la ecología alimentaria en los peces damisela, lo que contribuye al conocimiento de estos ecosistemas marinos y su gestión.

The feeding and morphology of the food system of the damselfish Stegastes acapulcoensis in La Entrega Bay, Oaxaca, was characterized to determine its trophic spectrum. In August 2022, 30 specimens of S. acapulcoensis were collected during the period of peak feeding activity, using homemade harpoons and SCUBA diving equipment. Samples were fixed with 5% formalin to preserve their tissues and facilitate prey identification. Each specimen was subjected to detailed biometric analysis, including measurements of total weight, total length, and standard length. Food components were identified and classified into nine categories, with algae standing out as the most consumed component, followed by detritus and invertebrates. The Relative Importance Index (%IIR) confirmed the importance of these components in the diet of S. acapulcoensis. Trophic spectrum analysis revealed that this species is a generalist predator, with a diet encompassing a moderate diversity of food components. In addition, a significant positive correlation was found between the weight of individuals and their consumption of algae, suggesting a relationship between size and feeding habits. The morphology of the food system, including the mandibular apparatus and pharyngeal plates, supported the adaptation of S. acapulcoensis to an opportunistic herbivore. The incisor teeth and pharyngeal plate characteristics indicated a specialization in the capture and processing of plant foods. Taken together, these findings provided a comprehensive view of the feeding ecology of S. acapulcoensis in La Entrega, highlighting the importance of algae in its diet and its ability to adjust to different food sources. In addition, our understanding of the relationship between morphology and feeding ecology in damselfish was expanded, contributing to the knowledge of these marine ecosystems and their management.

Dieta, ecología, morfología mandibular Diet, ecology, jaw morphology BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA OTRAS ESPECIALIDADES DE LA BIOLOGÍA OTRAS OTRAS

Stability of FeVO4-II under Pressure: A First-Principles Study

PRICILA BETBIRAI ROMERO VAZQUEZ SINHUE LOPEZ MORENO Daniel Errandonea (2022, [Artículo])

"In this work, we report first-principles calculations to study FeVO4 in the CrVO4-type (phase II) structure under pressure. Total-energy calculations were performed in order to analyze the structural parameters, the electronic, elastic, mechanical, and vibrational properties of FeVO4-II up to 9.6 GPa for the first time. We found a good agreement in the structural parameters with the experimental results available in the literature. The electronic structure analysis was complemented with results obtained from the Laplacian of the charge density at the bond critical points within the Quantum Theory of Atoms in Molecules methodology. Our findings from the elastic, mechanic, and vibrational properties were correlated to determine the elastic and dynamic stability of FeVO4-II under pressure. Calculations suggest that beyond the maximum pressure covered by our study, this phase could undergo a phase transition to a wolframite-type structure, such as in CrVO4 and InVO4."

FeVO4 under pressure CrVO4-type structure First-principles Mechanical properties Vibrational properties Electronic properties CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA FÍSICA DEL ESTADO SÓLIDO CRISTALOGRAFÍA CRISTALOGRAFÍA

The cerato-mandibular ligament: a key functional trait for grazing in damselfishes (Pomacentridae)

Damien Olivier Bruno Frederich MILTON ALEJANDRO SPANOPOULOS ZARCO Eduardo Francisco Balart Páez Eric Parmentier (2014, [Artículo])

"The success of a taxonomic group can be promoted by a key character that allows the group to interact with its environment in a different way and to potentially occupy new niches. The Pomacentridae possess a synapomorphic trait, the cerato-mandibular (c-md) ligament, which joins the hyoid bar to the inner part of the lower jaw. It has previously been shown that this ligament is a key trait in communication in damselfishes because it enables them to slam the oral jaws shut causing teeth collision and sound production. This specific behavior of mouth closing could, however, also be used for other tasks, such as feeding. Many territorial damselfishes are referred to as farmers, due to their ability to manage algal crops on which they feed. This study hypothesizes that the c-md ligament provides an advantage for grazing filamentous algae, and should thus be considered a key trait for farming behavior."

Biomechanics, Evolution, Farming, Functional morphology BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) ZOOLOGÍA MARINA ZOOLOGÍA MARINA

Nitrogen fertilizer application alters the root endophyte bacterial microbiome in maize plants, but not in the stem or rhizosphere soil

Alejandra Miranda Carrazco Yendi Navarro-Noya Bram Govaerts Nele Verhulst Luc Dendooven (2022, [Artículo])

Plant-associated microorganisms that affect plant development, their composition, and their functionality are determined by the host, soil conditions, and agricultural practices. How agricultural practices affect the rhizosphere microbiome has been well studied, but less is known about how they might affect plant endophytes. In this study, the metagenomic DNA from the rhizosphere and endophyte communities of root and stem of maize plants was extracted and sequenced with the “diversity arrays technology sequencing,” while the bacterial community and functionality (organized by subsystems from general to specific functions) were investigated in crops cultivated with or without tillage and with or without N fertilizer application. Tillage had a small significant effect on the bacterial community in the rhizosphere, but N fertilizer had a highly significant effect on the roots, but not on the rhizosphere or stem. The relative abundance of many bacterial species was significantly different in the roots and stem of fertilized maize plants, but not in the unfertilized ones. The abundance of N cycle genes was affected by N fertilization application, most accentuated in the roots. How these changes in bacterial composition and N genes composition might affect plant development or crop yields has still to be unraveled.

Bacterial Community Structure DArT-Seq Bacterial Community Functionality Genes Involved in N Cycling CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGRICULTURAL PRACTICES MAIZE RHIZOSPHERE STEMS NITROGEN FERTILIZERS