Redmond’s Midtown Neighborhood: Five Visions

97 pagesIn the fall term of 2015, graduate planning students at the University of Oregon developed concept plans for the Midtown Neighborhood in Redmond, Oregon. Redmond wanted ideas for revitalizing Midtown, an area seen as struggling somewhat given its adjacency to the city’s revitalized downtown core. As part of this project, the city also asked the student teams to examine the neighborhood through the lens of its Great Neighborhood Planning Principles, a set of guidelines the city had adopted for new development, to see if there were ways the principles could be better adapted to existing neighborhoods. Common elements such as background research, site analysis, and an overall analysis of the Great Neighborhood Principles are presented as a synthesis of the teams’ findings. Each team’s vision for the neighborhood is also presented

Exposure to bacterial signals does not alter pea aphids' survival upon a second challenge or investment in production of winged offspring

Pea aphids have an obligate nutritional symbiosis with the bacteria Buchneraaphidicola and frequently also harbor one or more facultative symbionts. Aphids are also susceptible to bacterial pathogen infections, and it has been suggested that aphids have a limited immune response towards such pathogen infections compared to other, more well-studied insects. However, aphids do possess at least some of the genes known to be involved in bacterial immune responses in other insects, and immune-competent hemocytes. One possibility is that immune priming with microbial elicitors could stimulate immune protection against subsequent bacterial infections, as has been observed in several other insect systems. To address this hypothesis we challenged aphids with bacterial immune elicitors twenty-four hours prior to live bacterial pathogen infections and then compared their survival rates to aphids that were not pre-exposed to bacterial signals. Using two aphid genotypes, we found no evidence for immune protection conferred by immune priming during infections with either Serratia marcescens or with Escherichia coli. Immune priming was not altered by the presence of facultative, beneficial symbionts in the aphids. In the absence of inducible immune protection, aphids may allocate energy towards other defense traits, including production of offspring with wings that could escape deteriorating conditions. To test this, we monitored the ratio of winged to unwinged offspring produced by adult mothers of a single clone that had been exposed to bacterial immune elicitors, to live E. coli infections or to no challenge. We found no correlation between immune challenge and winged offspring production, suggesting that this mechanism of defense, which functions upon exposure to fungal pathogens, is not central to aphid responses to bacterial infections.Toxicolog

Assisted protein folding at low temperature: evolutionaryadaptation of the Antarctic fish chaperonin CCT and its clientproteins

Eukaryotic ectotherms of the Southern Ocean face energetic challenges to protein folding assisted by the cytosolic chaperonin CCT. We hypothesize that CCT and its client proteins (CPs) have co-evolved molecular adaptations that facilitate CCT–CP interaction and the ATP-driven folding cycle at low temperature. To test this hypothesis, we compared the functional and structural properties of CCT–CP systems from testis tissues of an Antarctic fish, Gobionotothen gibberifrons (Lo¨nnberg) (habitat/body T=-1.9 to +2˚C), and of the cow (body T=37˚C). We examined the temperature dependence of the binding of denatured CPs (bactin, b-tubulin) by fish and bovine CCTs, both in homologous and heterologous combinations and at temperatures between 24˚C and 20˚C, in a buffer conducive to binding of the denatured CP to the open conformation of CCT. In homologous combination, the percentage of G. gibberifrons CCT bound to CP declined linearly with increasing temperature, whereas the converse was true for bovine CCT. Binding of CCT to heterologous CPs was low, irrespective of temperature. When reactions were supplemented with ATP, G. gibberifrons CCT catalyzed the folding and release of actin at 2˚C. The ATPase activity of apo-CCT from G. gibberifrons at 4˚C was, 2.5-fold greater than that of apo-bovine CCT, whereas equivalent activities were observed at 20˚C. Based on these results, we conclude that the catalytic folding cycle of CCT from Antarctic fishes is partially compensated at their habitat temperature, probably by means of enhanced CP-binding affinity and increased flexibility of the CCT subunits

Life-history strategy determines constraints on immune function

Determining the factors governing investment in immunity is critical to understanding host-pathogen ecological and evolutionary dynamics. Studies often consider disease resistance in the context of life-history theory, with the expectation that investment in immunity will be optimized in anticipation of disease risk. Immunity, however, is constrained by context-dependent fitness costs. How the costs of immunity vary across life-history strategies has yet to be considered. Pea aphids are typically unwinged but produce winged offspring in response to high population densities and deteriorating conditions. This is an example of polyphenism, a strategy used by many organisms to adjust to environmental cues. The goal of this study was to examine the relationship between the fitness costs of immunity, pathogen resistance and the strength of an immune response across aphid morphs that differ in life-history strategy but are genetically identical. We measured fecundity of winged and unwinged aphids challenged with a heat-inactivated fungal pathogen, and found that immune costs are limited to winged aphids. We hypothesized that these costs reflect stronger investment in immunity in anticipation of higher disease risk, and that winged aphids would be more resistant due to a stronger immune response. However, producing wings is energetically expensive. This guided an alternative hypothesis - that investing resources into wings could lead to a reduced capacity to resist infection. We measured survival and pathogen load after live fungal infection, and we characterized the aphid immune response to fungi by measuring immune cell concentration and gene expression. We found that winged aphids are less resistant and mount a weaker immune response than unwinged aphids, demonstrating that winged aphids pay higher costs for a less effective immune response. Our results show that polyphenism is an understudied factor influencing the expression of immune costs. More generally, our work shows that in addition to disease resistance, the costs of immunity vary between individuals with different life-history strategies. We discuss the implications of these findings for understanding how organisms invest optimally in immunity in the light of context-dependent constraints

Las Secuencias Depositacionales del Plioceno-Cuaternario en la Plataforma Submarina adyacente al Litoral del Este Bonaerense

Se describen las características sismoestratigráficas, sedimentológicas y morfológicas del sector de plataforma submarina adyacente al este bonaerense. El trabajo se basa en los resultados obtenidos durante el desarrollo de sucesivos proyectos destinados al estudio de la cubierta sedimentaria del Plioceno-Cuaternario y reciente, utilizando metodologías de relevamiento sísmico de reflexión de media a alta resolución y muestreos de sedimentos. El sector de plataforma estudiado constituye una típica plataforma submarina silicoclástica de margen pasivo, de gran extensión y suave relieve. Su configuración morfológica está caracterizada por relieves aterrazados con una cobertura sedimentaria de depósitos arenosos relicto a palimpsestos que resultaron del retrabajamiento de sistemas costeros de playas, barreras y lagunas litorales durante el retroceso de la línea de costa como consecuencia del ascenso del nivel del mar durante la transgresión postglacial, con una etapa final de remodelado parcial durante el descenso del nivel del mar del Holoceno superior. Se diferencian dos ámbitos, la plataforma interior ("Terraza Rioplatense", entre la línea de costa y los 30/40 m de profundidad) con geoformas ajustadas a la hidrodinámica actual, y la plataforma exterior (entre la isobata de 70 m y el borde exterior de la plataforma en transición al talud), con sedimentos relicto de poca movilidad; en ambas se hallan relieves pre-transgresivos labrados en depósitos marinos y continentales del Plio-Pleistoceno que afloran bajo la cubierta sedimentaria reciente. Un escalón abrupto de 30/40 m de desnivel separa ambas plataformas. La secuencia estratigráfica estudiada está constituida por seis Secuencias Depositacionales (SD 1 a SD 6 de techo a base) que representan paquetes sedimentarios separados por discordancias. La SD 6 constituye la base de la secuencia, y corresponde a depósitos marinos del Mioceno correlacionables con las unidades costeras conocida como "Paranense-Entrerriense-Chapadmalense". La SD 5 son depósitos marinos en transición a continentales equivalentes a la Fm Barranca de los Lobos del litoral marplatense y a la unidad conocida como "Fm Puelches Equivalente" del Plioceno. La SD 4 está caracterizada por sedimentos marinos correspondientes al denominado "Interensenadense" en el litoral bonaerense, de edad aproximada a los 2,41 Ma (Plioceno superior), y se reconocen en ella diversas sismofacies de ambientes marinos, costeros y continentales con una secuencia litológica granodecreciente hacia arriba. La SD 3, marina, tiene la particularidad de tener una distribución saltuaria, a diferencia de las restantes que se extienden de manera uniforme en toda la región, lo que demuestra la ocurrencia, con posterioridad a su depositación, de importantes procesos erosivos probablemente asociados a tectónica y/o glacioeustatismo. La SD 2 representa a los depósitos marinos-costeros formados durante el estadío isotópico 5e (120 ka), que en las llanuras costeras vecinas se lo conoce como "Belgranense", y está constituida por diversas facies entre las que se destacan barreras-lagunas litorales, playas y estuarios. La SD 1 es la cobertura superficial formada durante la transgresión postglacial en ambientes de barreras-lagunas costeras-estuarios. La secuencia integrada por las SD 5 a 1 representa a las transgresiones glacioeustáticas del Plioceno- Cuaternario, con diferentes grados de preservación en la plataforma y el Río de la Plata en virtud de variantes tectónicas y morfológicas. Existe la posibilidad de que no todas las transgresiones marinas ocurridas en la región hayan quedado preservadas en el registro geológico

Analysis of two-player quantum games in an EPR setting using geometric algebra

The framework for playing quantum games in an Einstein-Podolsky-Rosen (EPR) type setting is investigated using the mathematical formalism of Clifford geometric algebra (GA). In this setting, the players' strategy sets remain identical to the ones in the classical mixed-strategy version of the game, which is then obtained as proper subset of the corresponding quantum game. As examples, using GA we analyze the games of Prisoners' Dilemma and Stag Hunt when played in the EPR type setting.Comment: 20 pages, no figure, revise

The RS Oph outburst of 2021 monitored in X-rays with NICER

The 2021 outburst of the symbiotic recurrent nova RS Oph was monitored with the Neutron Star Interior Composition Explorer Mission (NICER) in the 0.2-12 keV range from day one after the optical maximum, until day 88, producing an unprecedented, detailed view of the outburst development. The X-ray flux preceding the supersoft X-ray phase peaked almost 5 days after optical maximum and originated only in shocked ejecta for 21 to 25 days. The emission was thermal; in the first 5 days only a non-collisional-ionization equilibrium model fits the spectrum, and a transition to equilibrium occurred between days 6 and 12. The ratio of peak X-rays flux measured in the NICER range to that measured with Fermi in the 60 MeV-500 GeV range was about 0.1, and the ratio to the peak flux measured with H.E.S.S. in the 250 GeV-2.5 TeV range was about 100. The central supersoft X-ray source (SSS), namely the shell hydrogen burning white dwarf (WD), became visible in the fourth week, initially with short flares. A huge increase in flux occurred on day 41, but the SSS flux remained variable. A quasi-periodic oscillation every ~35 s was always observed during the SSS phase, with variations in amplitude and a period drift that appeared to decrease in the end. The SSS has characteristics of a WD of mass >1 M(solar). Thermonuclear burning switched off shortly after day 75, earlier than in 2006 outburst. We discuss implications for the nova physics.Comment: Accepted for publication in the Astrophysical Journa

Heritability of symbiont density reveals distinct regulatory mechanisms in a tripartite symbiosis

Beneficial eukaryotic–bacterial partnerships are integral to animal and plant evolution. Understanding the density regulation mechanisms behind bacterial symbiosis is essential to elucidating the functional balance between hosts and symbionts. Citrus mealybugs, Planococcus citri (Risso), present an excellent model system for investigating the mechanisms of symbiont density regulation. They contain two obligate nutritional symbionts, Moranella endobia, which resides inside Tremblaya princeps, which has been maternally transmitted for 100–200 million years. We investigate whether host genotype may influence symbiont density by crossing mealybugs from two inbred laboratory-reared populations that differ substantially in their symbiont density to create hybrids. The density of the M. endobia symbiont in the hybrid hosts matched that of the maternal parent population, in keeping with density being determined either by the symbiont or the maternal genotype. However, the density of the T. princeps symbiont was influenced by the paternal host genotype. The greater dependency of T. princeps on its host may be due to its highly reduced genome. The decoupling of T. princeps and M. endobia densities, in spite of their intimate association, suggests that distinct regulatory mechanisms can be at work in symbiotic partnerships, even when they are obligate and mutualistic

Immunity and other defenses in pea aphids, Acyrthosiphon pisum

The genome of the pea aphid Acyrthosiphon pisum lacks genes thought to be crucial in other insects for recognition, signaling and killing of microbes

Costs and benefits of sub-lethal Drosophila C Virus infection

Viruses are major evolutionary drivers of insect immune systems. Much of our knowledge of insect immune responses derives from experimental infections using the fruit fly Drosophila melanogaster. Most experiments, however, employ lethal pathogen doses through septic injury, frequently overwhelming host physiology. While this approach has revealed several immune mechanisms, it is less informative about the fitness costs hosts may experience during infection in the wild. Using both systemic and oral infection routes we find that even apparently benign, sub-lethal infections with the horizontally transmitted Drosophila C Virus (DCV) can cause significant physiological and behavioral morbidity that is relevant for host fitness. We describe DCV-induced effects on fly reproductive output, digestive health, and locomotor activity, and we find that viral morbidity varies according to the concentration of pathogen inoculum, host genetic background and sex. Notably, sub-lethal DCV infection resulted in a significant increase in fly reproduction, but this effect depended on host genotype. We discuss the relevance of sub-lethal morbidity for Drosophila ecology and evolution, and more broadly, we remark on the implications of deleterious and beneficial infections for the evolution of insect immunity