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Asymptotic Matrix Behaviors and Iterative Algorithms
Get PDFThis presentation examines the asymptotic behavior of matrix iterations, focusing on the QR and LR algorithms and their significance in eigenvalue computation. It highlights foundational developments by Rutishauser, Francis, and Kublanovskaya and modern refinements by Huang and Tam, particularly on matrix decompositions and spectral properties. Extensions of Yamamoto’s theorem, including recent works by Nayak and Shekhawat, and Huang and Tam, are discussed, connecting iterative processes to spectral radius formulas and Jordan decompositions. This is a joint work with Huajun Huang of Auburn University
Elemental Mimicry in Seal Teeth Reveal More Than You Realize
No full textThe South American sea lions and Peruvian fur seals residing along the Pacific coast of Peru are important apex marine predators as well as threatened marine mammals within the Humboldt Current upwelling marine ecosystem. These pinniped species have undergone extreme population fluctuations over the past century due to natural and anthropogenic events. Environmental contaminates from Peru’s expanding coastal mining activities in the vicinity of Punta San Juan, combined with El Niño-Southern Oscillation (ENSO) events, may influence the concentration of trace elements incorporated into teeth structure. Pinniped teeth consist of annual growth layer groups (GLGs) which provide fine-scale resolution of contaminant incorporation over the animals’ lifetime. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) provided both transect and point sampling across 3 to 10 GLGs (years). Sampling at an oblique angle across the GLGs provides greater resolution in contaminate concentrations. The inorganic structure of the teeth allows for elemental replacement and bioaccumulation of some elements in question (As, Ba, Cd, Cu, Fe, Li, Mg, Mn, Sr, Zn). The initial results indicate periods of high and low concentrations which may correspond to both seasonal and interannual variations. Some elements reveal apparent bioaccumulation, such as Cu and Li potentially related to near-coast mining, and interannual concentration differences (Ba and Sr) possibly correlated to diet differences concurrent with ENSO events. These elemental fluctuations were analyzed while considering periodic ENSO events and the influence of sea surface temperature anomalies. Temperature reflects the intensity of up- and downwelling and its impact on ocean production, which can alter the pinnipeds’ prey base and influence elemental concentrations
Predicting Demography From Species Traits: Larval Development Time and its Sensitivity to Warming Depend on Egg Size in Corals
No full textIn the absence of demographic data, readily measurable life history traits, like egg size, can be used to predict how vital rates vary across species, facilitating modeling and analysis of high-diversity assemblages. We assessed the larval survival and competency dynamics of four previously unstudied coral species at current and warmed temperatures, and combined it with data for three other species to assess how well egg size predicts mortality and the minimum time to competency, both determinants of larval dispersal. Minimum time to competency increased with egg size; moreover, warming-induced reductions in time to competency were greater for species with larger eggs. In contrast, morality rate and its response to warming were both independent of egg size. These findings show how assemblage-level responses to environmental change can be projected in diverse communities, and indicate how warming-induced changes in larval biology may reshape reef coral metacommunities
Pacific Pit Stops: Leveraging Genomics to Understand Scalloped Hammerhead Aggregations in the Galapagos Islands
No full textAuthors:
Geoffrey Walker1,2, Andrea Bernard1, Pelayo Salinas-de-León1,3, Jennifer Suarez-Moncada4, Mahmood Shivji1,2
1. Save Our Seas Foundation Shark Research Center, HCAS, NSU
2. Guy Harvey Research Institute, HCAS, NSU
3. Charles Darwin Research Station, Charles Darwin Foundation, Galapagos Islands, Ecuador
4. Galapagos National Park Directorate, Galapagos Islands, Ecuador.
Scalloped hammerhead sharks (Sphyrna lewini; IUCN Red List: Critically Endangered) form iconic seasonal aggregations around Wolf and Darwin Islands in the Galápagos (Eastern Tropical Pacific). The genetic characteristics of these mainly adult aggregating sharks are unknown. Through collaboration with the Charles Darwin Foundation and Parque Nacional Galápagos, and as part of our satellite tag tracking studies on this species, we collected biopsy tissue samples from free-swimming sharks from 2016 to 2023 and are investigating the comparative genetic health and resilience of these aggregations. In this study, we employ a reduced representation genomic approach to obtain high-resolution single nucleotide polymorphism (SNP) genotype data from the Galápagos aggregating scalloped hammerheads, as well as non-aggregating adults of this species near Seychelles (Western Indian Ocean) and Florida (Western North Atlantic). Initial data analysis on population genetic differentiation and diversity shows clear genetic divergence among the three geographic groups, and much higher diversity in the sharks from Indo-Pacific (Seychelles and Galápagos) than Western North Atlantic (Florida). The genotype data are also being used to investigate whether genetic relatedness exists in the annually aggregating Galápagos sharks and if individuals sampled return to the aggregation over multiple years.
This project conducted under Permit MAE-DBI-CM-2021-0209 from the Ecuador Ministry of Environment
Sharks in the Parks: Use of MPAs by Silky Sharks, Carcharhinus falciformis, in the Eastern Tropical Pacific
No full textMarine protected areas (MPAs) are increasingly being used to protect at risk species, however, their effectiveness in protecting wide-ranging species is unclear. The silky shark (Carcharhinus falciformis) has experienced large declines in the Eastern Tropical Pacific and may benefit from the network of MPAs in the region. We examined silky shark use of MPAs and fisheries overlap by tracking 38 sub-adult and adult silky sharks tagged within the Galapagos Marine Reserve (GMR) with satellite tags for periods of up to 639 d. Based on movement patterns, sharks were split into three groups: males, eastern females, and western females. Sharks from all groups tended to show site fidelity to the GMR and the GMR was the most used MPA. Use of MPAs varied little between the wet (Dec-May) and dry seasons (Jun-Nov) for males and eastern females; males and eastern females spent ~55% and ~70% of their time within MPAs, respectively. Western females spent more time within MPAs during the wet season (~50%) compared to the dry season (~15%). Combining silky shark space use with fishing effort data from Global Fishing Watch revealed that sharks were most at risk from fisheries during the dry season within the northern Galapagos EEZ. Risk was much lower in the wet season; however, Global Fishing Watch data severely underestimates fishing effort in the region. Overall, for a wide-ranging species, silky sharks spent a great deal of time within the protected waters of the GMR, but much of their movements extended far beyond the GMR and other MPAs, putting them at risk from commercial fisheries operating in the Eastern Tropical Pacific
Simulation-Based Assessment of Blood Pressure by Certified Athletic Trainers
No full textPurpose: Blood pressure (BP) assessment is a key component of pre-participation examinations and can aid athletic trainers (ATs) in diagnosing hypertension. However, the current pedagogical technique, which involves practicing BP assessment on healthy individuals, may not adequately prepare healthcare providers to recognize Korotkoff sounds at abnormal pressures during clinical practice. Therefore, the purpose of this study was to examine AT\u27s ability to and confidence in assessing and interpreting BP using a high-fidelity simulator.
Methods: We recruited ATs through conferences, in-services, and postprofessional athletic training programs. In total, 100 ATs from various job settings (age=31±11 years; men=37, women=63, clinical experience=8±10 years; self-identified hearing concerns=31; previous simulation experience=36) completed the cross-sectional study focused on descriptive quality assurance. First, participants verbally reported the professional guidelines they used in clinical practice to interpret findings. Second, ATs completed a practice trial BP assessment to familiarize themselves with the provided stethoscope, cuff, and high-fidelity manikin. Then, ATs completed 3 randomized BP assessment trials out of 11 pre-set BP cases. Participants reported the systolic and diastolic reading, interpretation (hypotension, hypertension, normal), and their confidence (0%=no confidence, 100%=complete confidence) in assessing the BP and the interpretation for that case. Assessment correctness scores were calculated by case, with each correct systolic or diastolic value within a ±5 mmHg range counting as 1 and each incorrect value as 0.
Results: Most participants (n=48) used the American Heart Association BP interpretation guidelines. Participants had a low overall assessment correctness score (42.67±20.88%) with only 50% of the systolic values (n=150; mean difference=-5.85±13.32) and 68.7% of the diastolic values (n=206; mean difference=-0.34±9.60) reported within ±5 mmHg. Participants were most accurate with Case 5 (normal) and least accurate with Case 2 (hypertensive). The participants correctly interpreted the BP by their reported guidelines in 56.3% of the trials (n=169). Despite the substandard performance, participants expressed high confidence in BP assessment (80±16%) and interpretation (87±16%).
Conclusions: We identified a confidence-to-practice gap using simulation-based assessment with ATs having low achievement in assessing and interpreting BP despite their high confidence levels
Efectividad del Liderazgo Femenino en la Gestión Universitaria de Puerto Rico
No full textEsta investigación tuvo como propósito determinar la efectividad del liderazgo femenino en la gestión universitaria de programas de ciencias de la enfermería en el área Noroeste de Puerto Rico. La teoría que se utilizó en la investigación fue la Teoría del Liderazgo Transformacional de Bass (1985). El diseño de esta investigación fue descriptivo y cuantitativo. La población a impactar son mujeres profesionales de enfermería con un puesto de liderazgo de una institución educativa del área Noroeste de Puerto Rico y la muestra por conveniencia fue de 12 participantes.
Para recopilar la data se utilizó el instrumento “Efectividad y Estilos del Liderazgo Femenino en la Gestión Universitaria , con tres secciones: datos sociodemográficos; Factores y Retos en la Efectividad del Liderazgo Femenino; y el Multifactor Leadership Questionnaire (MLQ-5X forma corta) elaborado por Bass y Avolio (1995), adaptado por Vega y Zavala (2004). El cuestionario fue enviado por medio electrónico y se utilizó el programa Statistical Package for the Social Sciences (SPSS), versión 25, para tabular los datos.
Los hallazgos evidenciaron que el estilo de liderazgo predominante es el liderazgo Transformacional, caracterizado por altos niveles en las dimensiones de influencia idealizada, motivación inspiracional, estimulación intelectual y consideración individualizada. Además, las participantes demostraron una alta autopercepción de efectividad y satisfacción en su gestión, lo cual refuerza la visión de un liderazgo comprometido, ético y centrado en el desarrollo del equipo. Como factores que contribuyen a su efectividad, se destacaron el dominio de competencias y habilidades profesionales, seguido de la gestión académica, la efectividad interpersonal y, en menor grado, el género. También se identificaron retos importantes, tales como la dificultad para equilibrar el rol profesional con las responsabilidades familiares, la percepción negativa al ejercer autoridad y la existencia de desigualdad en las oportunidades de liderazgo por género
Participant Empowerment, Inclusivity, and Social Justice: A Review of Meng Tian’s Arts-Based Research Methods for Educational Researchers
No full textIn reviewing Arts-Based Research Methods for Educational Researchers by Meng Tian (2023), I found a priceless resource for contemporary scholars wishing to add cutting-edge arts-based techniques to their qualitative research inquiries. This book offers a thorough examination of how artistic mediums like poetry, theater, and visual arts can be used to investigate the emotional, psychological, and cultural aspects of education that conventional research frequently ignores. It does this by fusing theoretical understanding with helpful advice. The book focuses on participant empowerment, inclusivity, and ethical considerations when working with vulnerable populations highlights the book’s commitment to social justice, making it especially relevant in today’s educational context. Through concrete examples and case studies, the book illustrates how arts-based methods can be applied in diverse educational settings, bridging the gap between theory and real-world application. This practical emphasis makes the book particularly beneficial for novice and seasoned researchers, offering tools to navigate the moral and emotional complexities inherent in arts-based research. The book also addresses contemporary challenges; encouraging researchers to adapt and innovate in their approaches to educational inquiry. These are remarkable aspects of the book that I particularly valued in my review
Herramientas Tecnológicas Implementadas Por los Docentes de Matemáticas a Nivel Superior y Su Relación Con los Años en Servicio en el Sistema Educativo
No full textEl propósito de realizar la investigación fue identificar las herramientas tecnológicas educativas de mayor uso y la frecuencia con la cual los docentes especialistas en matemáticas lo utilizan en sus clases. Adicional determinar si existe alguna relación entre los años de servicio y la cantidad de herramientas tecnológicas utilizadas por los maestros.
La metodología del trabajo de investigación fue cuantitativa descriptiva correlacional no experimental transversal. La investigación se enfocó en trabajar con los maestros especialista en matemáticas del nivel superior de las escuelas del sistema público de enseñanza de Puerto Rico. Los docentes participantes fueron de varias escuelas del área este de Puerto Rico.
La recolección de los datos fue realizada mediante la contestación de un cuestionario que constó de 16 ítems. Las preguntas del cuestionario se contestaron mediante selección múltiple y escala de Likert. Los ítems que fueron contestados utilizando la escala de Likert se enfocaron en identificar las herramientas tecnológicas que más utilizaban y la frecuencia de uso en las áreas de planificación y organización, elaboración y contenido del curso, uso en las evaluaciones de los estudiantes y del curso e integradas en las clases de matemáticas.
Los resultados obtenidos identificaron cuales fueron las herramientas tecnológicas más utilizada y la frecuencia con que la utilizan los docentes del programa de matemáticas de las escuelas públicas de Puerto Ricos. Adicional se estableció la existencia leve de la relación entre las herramientas tecnológicas implementadas y los años de experiencia o de servicio como maestro