Behavioral correlates of semi-zygodactyly in Ospreys (Pandion haliaetus) based on analysis of internet images

Ospreys are renowned for their fishing abilities, which have largely been attributed to their specialized talon morphology and semi-zygodactyly−the ability to rotate the fourth toe to accompany the first toe in opposition of toes II and III. Anecdotal observations indicate that zygodactyly in Ospreys is associated with prey capture, although to our knowledge this has not been rigorously tested. As a first pass toward understanding the functional significance of semi-zygodactyly in Ospreys, we scoured the internet for images of Osprey feet in a variety of circumstances. From these we cross-tabulated the number of times each of three toe configurations (anisodactylous, zygodactylous, and an intermediate condition between these) was associated with different grasping scenarios (e.g., grasping prey or perched), contact conditions (e.g., fish, other objects, or substrate), object sizes (relative to foot size), and grasping behaviors (e.g., using one or both feet). Our analysis confirms an association between zygodactyly and grasping behavior; the odds that an osprey exhibited zygodactyly while grasping objects in flight were 5.7 times greater than whilst perched. Furthermore, the odds of zygodactyly during single-foot grasps were 4.1 times greater when pictured grasping fish compared to other objects. These results suggest a functional association between predatory behavior and zygodactyly and has implications for the selective role of predatory performance in the evolution of zygodactyly more generally

Behavioral correlates of semi-zygodactyly in Ospreys (Pandion haliaetus) based on analysis of internet images

Ospreys are renowned for their fishing abilities, which have largely been attributed to their specialized talon morphology and semi-zygodactyly-the ability to rotate the fourth toe to accompany the first toe in opposition of toes II and III. Anecdotal observations indicate that zygodactyly in Ospreys is associated with prey capture, although to our knowledge this has not been rigorously tested. As a first pass toward understanding the functional significance of semi-zygodactyly in Ospreys, we scoured the internet for images of Osprey feet in a variety of circumstances. From these we cross-tabulated the number of times each of three toe configurations (anisodactylous, zygodactylous, and an intermediate condition between these) was associated with different grasping scenarios (e.g., grasping prey or perched), contact conditions (e.g., fish, other objects, or substrate), object sizes (relative to foot size), and grasping behaviors (e.g., using one or both feet). Our analysis confirms an association between zygodactyly and grasping behavior; the odds that an osprey exhibited zygodactyly while grasping objects in flight were 5.7 times greater than whilst perched. Furthermore, the odds of zygodactyly during single-foot grasps were 4.1 times greater when pictured grasping fish compared to other objects. These results suggest a functional association between predatory behavior and zygodactyly and has implications for the selective role of predatory performance in the evolution of zygodactyly more generally

Biomechanics of Feeding in Loggerhead Shrikes

A major thrust of organismal biology involves understanding how an organism’s phenotype relates to its environment, via its performance capabilities. I investigated this linkage in Loggerhead Shrikes − small North American predatory songbirds that feed on arthropods and vertebrates, whose physical and behavioral attributes differ substantially. My dissertation is composed of three components, aimed at uncovering how shrikes accommodate the disparate demands of their prey. I examined geographic variation in bill morphology of museum specimens to investigate the relationship between environmental factors and upper bill form, particularly of the hooked tip and tomial teeth, which are thought to play a key role for processing vertebrate prey. My geometric morphometric analysis revealed significant intra- and interspecific variation, mostly along an axis of increasing hook curvature and length. Whereas as dietary differences mostly explained bill shape variation among species, variance in temperature and longitude explained variation within Loggerhead Shrikes. My field component was aimed at understanding the functional and ecological consequences of morphological variation. I captured shrikes throughout California to measure bill morphology and bite performance. I collected feather and prey samples for stable isotopes analysis, to infer dietary variation. Increased bill and hook lengths and curvatures were associated with lower bite forces, whereas bill shape was unrelated to bite pressure (force/area). Thus, shrikes with different bill shapes may achieve functional equivalence by modulating bite force. Bite force, rather than bill shape, was associated with isotopic variation, and with greater consumption of vertebrates. This suggested the importance of bite performance for handling less tractable prey, and possibly for responding to spatiotemporal variation in resources. Finally, I studied how prey-processing varied with prey type and ontogeny in captive shrikes. I performed high-speed video kinematics of adult and juvenile shrikes attacking crickets and mice. My results suggested that the head-shaking behavior that shrikes use when handling vertebrates may enhance killing efficiency. Although there were few differences between age classes in procuring crickets, juveniles had greater difficulty handling mice, consistent with their reduced bill hook and tomial tooth lengths. Collectively, these results demonstrate how functional performance mediates the relationship between morphology and feeding ecology in shrikes

Feeding in Birds: Thriving in Terrestrial, Aquatic, and Aerial Niches

We start with a general description of the structure of the feeding apparatus in birds (Sect. 17.1), then we describe the biomechanics of those parts (Sect. 17.2), including a review of contemporary approaches to the study of bird feeding morphology and function. We establish explicit links between form and function, and consequent relations to foraging behaviors. In Sect. 17.3, we systematically explore the vast diversity of bird feeding environments by grouping foraging (searching) and feeding (handling—consumption) mechanisms that birds use on land, air, and water. Each one of these subsections addresses not only what birds eat, but also how they feed. We dedicate a separate Sect. (17.4) to drinking because most birds have to perform this process regardless of their diet, and often using different mechanisms than the ones they use to feed. We then discuss evolutionary forces and patterns in bird feeding (convergences, radiations, trade-offs, etc.), including functions different from handling and ingestion that also act to shape the feeding apparatus in birds (Sect. 17.5)

Insights on the Molecular Behavior of Polypropylene in the Process of Ultrasonic Injection Molding

Product miniaturization is a constant trend in industries that demand ever-smaller products that can be mass produced while maintaining high precision dimensions in the final pieces. Ultrasonic micro injection molding (UMIM) technology has emerged as a polymer processing technique capable of achieving the mass production of polymeric parts with micro-features, while still assuring replicability, repeatability, and high precision, contrary to the capabilities of conventional processing technologies of polymers. In this study, it is shown that the variation of parameters during the UMIM process, such as the amplitude of the ultrasound waves and the processing time, lead to significant modification on the molecular structure of the polymer. The variation of both the amplitude and processing time contribute to chain scission; however, the processing time is a more relevant factor for this effect as it is capable of achieving a greater chain scission in different areas of the same specimen. Further, the presence of polymorphism within the samples produced by UMIM is demonstrated. Similarly to conventional processes, the UMIM technique leads to some degree of chain orientation, despite the fact that it is carried out in a relatively small time and space. The results presented here aim to contribute to the optimization of the use of the UMIM process for the manufacture of polymeric micro parts

El Ojo de Orfeo : visiones contemporáneas de la relación arte-tecnología

En El ojo de Orfeo desde puntos dispares y con estrategias escópicas diversas, los autores han asumido el compromiso de analizar la situación de prácticas artísticas y culturales de nuestros días, que dan lugar a las siguientes cuestiones.: ¿Cómo se reconfigura el arte hoy en un campo que incorpora la experiencia digital?; ¿Qué implicaciones tiene la redefinición digital de la experiencia socio-cultural sobre las concepciones y procesos de creación artística? ¿Cuáles son los limites de la técnica en las prácticas artísticas actuales? Es un trabajo planteado en términos interdisciplinarios, que investiga los vínculos del arte con otras manifestaciones culturales, manteniendo en primer plano la pregunta por lo técnico. Las ciencias sociales y las humanidades concurren buscando a un tiempo una clarificación y una problematización de la condición del arte en nuestros días. Las y los investigadores aquí convocados provienen de diversas formaciones académicas, y de distintas instituciones de enseñanza superior (Universidad Complutense de Madrid, UAM-Xochimilco, Universidad de Zacatecas, Universidad de Guanajuato, Universidad de Vigo, Universidad del País Vasco) lo cual permite la generación de miradas en un diálogo donde se manifiestan las coincidencias tanto como las diferencias de interpretación y análisis. Rica visión de conjunto que contribuye a la construcción de un juego de miradas, polivalente y sutil, sobre la condición del arte en sus convergencias tecnológicas

Horrores estridentes : arte, violencia y ruina social

El horror y la estridencia son fantasmas de la violencia, signos que aparecen como negación de lo real [Dimensión social] y como realidad de la imaginación [Dimensión Humanística]. Es en este doble sentido, el real y el imaginario, que el libro Horrores estridentes presenta su propuesta de analizar la violencia en un diálogo transdisciplinario. En lo social se abordan las dimensiones de la violencia, desde su debate conceptual-histórico hasta el análisis de la realidad en México. El horror se vislumbra como la aparición de la destrucción de lo social y de la estructura cultural, en particular se conjetura la paradoja de que la violencia destructora de lo social es la misma que funda lo social. En la dimensión humanística los capítulos le dan Corpus a debates abiertos en el mundo contemporáneo, sugieren un aura de comprensión: los cuerpos intervenidos como metáfora artística, narconarrativa, resistencia y arte, justicia, mal e identidad, representan la apertura para la comprensión de la violencia social