Advance research on control systems for the Saturn launch vehicle Final report, Jan., 1964 - May, 1965

Minimax problem in control systems for Saturn launch vehicl

The Evolution of Multi-component Visual Signals in Darters (genus Etheostoma)

As complex traits evolve, each component of the trait may be under different selection pressures and could respond independently to distinct evolutionary forces. We used comparative methods to examine patterns of evolution in multiple components of a complex courtship signal in darters, specifically addressing the question of how nuptial coloration evolves across different areas of the body. Using spectral reflectance, we defined 4 broad color classes present on the body and fins of 17 species of freshwater fishes (genus Etheostoma) and quantified differences in hue within each color class. Ancestral state reconstruction suggests that most color traits were expressed in the most recent common ancestor of sampled species and that differences among species are mostly due to losses in coloration. The evolutionary lability of coloration varied across body regions; we found significant phylogenetic signal for orange color on the body but not for most colors on fins. Finally, patterns of color evolution and hue of the colors were correlated among the two dorsal fins and between the anterior dorsal and anal fins, but not between any of the fins and the body. The observed patterns support the hypothesis that different components of complex signals may be subject to distinct evolutionary pressures, and suggests that the combination of behavioral displays and morphology in communication may have a strong influence on patterns of signal evolution [Current Zoology 57 (2): 125–139, 2011]

Addendum: One‐Speed Neutron Transport in Two Adjacent Half‐Spaces

The interface current for the problem of two half‐spaces with a constant source in one half‐space is obtained in closed form.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70010/2/JMAPAQ-5-12-1804-1.pd

Sex and design in our evolutionary cousins: The perception of beauty in nature

Desde un enfoque evolutivo de la belleza, en este texto analizamos la expresión y la percepción de la belleza sexual en el reino animal. Los cerebros de los animales perciben la belleza y detectan las características del entorno que resultan más relevantes para su supervivencia. A lo largo de la evolución, los animales con reproducción sexual han explotado este proceso de detección para maximizar su atractivo para el sexo opuesto. Habitualmente, esto ha conllevado la aparición de comportamientos y rasgos de cortejo extremos. Estos son rasgos de belleza sexual. Combinando principios neurocientíficos y neuroestéticos modernos con otros provenientes de la biología evolutiva, tratamos de entender las bases biológicas y la evolución de la belleza en todos los animales, incluidos nosotros mismos.; Des d’un enfocament evolutiu de la bellesa, en aquest text analitzem l’expressió i la percepció de labellesa sexual en el regne animal. Els cervells dels animals perceben la bellesa i detecten les característiquesde l’entorn que resulten més rellevants per a la seua supervivència. Al llarg de l’evolució,els animals amb reproducció sexual han explotat aquest procés de detecció per a maximitzar el seuatractiu per a l’altre sexe. Habitualment, això ha comportat l’aparició de comportaments i trets defesteig extrems. Aquests són trets de bellesa sexual. Combinant principis neurocientífics i neuroestèticsmoderns amb altres provinents de la biologia evolutiva, tractem d’entendre les bases biològiquesi l’evolució de la bellesa en tots els animals, inclosos nosaltres mateixos.; Taking an evolutionary approach to the question of beauty, we discuss the expression and perception of sexual beauty across the animal kingdom. Animals experience beauty in their brains, and animal brains are tuned to features of the environment most relevant to their survival. Over evolutionary time, sexually reproducing animals have exploited that tuning to maximize their attractiveness to the opposite sex, often leading to extreme courtship traits and behaviors. These are the traits of sexual beauty. Combining modern principles of neuroscience and neuroaesthetics with established principles of evolutionary biology, we aim to understand the biological basis and evolution of beauty in all animals, including ourselves

One‐Speed Neutron Transport in Two Adjacent Half‐Spaces

Using Case's method for solving the one‐speed transport equation with isotropic scattering, the Milne problem solution, the solution for a constant source in one half‐space, and the Green's function solution are obtained for two adjacent half‐spaces. These problems have been solved previously by other methods. Here the derivations are greatly simplified by using Case's method.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71048/2/JMAPAQ-5-5-668-1.pd

Calculations of the Performance of a Compression-Ignition Engine-Compressor Turbine Combination I : Performance of a Highly Supercharged Compression-Ignition Engine

Small high-speed single-cylinder compression-ignition engines were tested to determine their performance characteristics under high supercharging. Calculations were made on the energy available in the exhaust gas of the compression-ignition engines. The maximum power at any given maximum cylinder pressure was obtained when the compression pressure was equal to the maximum cylinder pressure. Constant-pressure combustion was found possible at an engine speed of 2200 rpm. Exhaust pressures and temperatures were determined from an analysis of indicator cards. The analysis showed that, at rich mixtures with the exhaust back pressure equal to the inlet-air pressure, there is excess energy available for driving a turbine over that required for supercharging. The presence of this excess energy indicates that a highly supercharged compression-ignition engine might be desirable as a compressor and combustion chamber for a turbine