Recent Investigations of Mission Period Activity on Sapelo Island, Georgia

Prior to their retreat to Florida in 1684, Muskogean-speaking Guale Indians inhabited much of what is now the Georgia coast. The arrival of Spanish missionaries in Florida and Georgia in the mid-1500s began what is known archaeologically as the mission period (1568-1684), a time of sustained interaction between the Spanish and the Guale people. Over time, population loss due to European-introduced diseases and conflict with English-backed Native American slave raiders resulted in a drastic reconfiguration of Guale society and the abandonment of the Guale\u27s ancestral homeland (Worth 2007). Sapelo Island (Figure 6.1) is the site of at least one Spanish mission, the Mission San Joseph de Sapala (Worth 2007:194). Ethnohistoric data indicate that this mission played a critical role in the story of Guale culture change, serving as an aggregation point for other Guale towns that were forced to relocate after attacks by slave raiders and pirates. Of particular interest is the period from ca. 1660 to 1684, when extensive demographic shuffling and relocation led to the mixing of many formerly separate Native American social entities and the emergence of the Yamassee, a newly formed but culturally distinct sociopolitical group made up of individuals from several collapsed chiefdoms (Saunders 2001; Worth 2004a, 2004b)

Topological synchronization of fractionalized spins

The gapped symmetric phase of the Affleck-Kennedy-Lieb-Tasaki (AKLT) model exhibits fractionalized spins at the ends of an open chain. We show that breaking SU(2) symmetry and applying a global spin-lowering dissipator achieves synchronization of these fractionalized spins. Additional local dissipators ensure convergence to the ground state manifold. In order to understand which aspects of this synchronization are robust within the entire Haldane-gap phase, we reduce the biquadratic term which eliminates the need for an external field but destabilizes synchronization. Within the ground state subspace, stability is regained using only the global lowering dissipator. These results demonstrate that fractionalized degrees of freedom can be synchronized in extended systems with a significant degree of robustness arising from topological protection.Comment: 5+1 pages, 2 figures, comments are welcom

SLIDES: Introduction to Constructive Engagement in the Oil and Gas Industry

Presenters: Susan T. Wildau and Christopher W. Moore, CDR Associates (Collaborative Decision Resources), Boulder, CO 22 slide

SLIDES: Introduction to Constructive Engagement in the Oil and Gas Industry

Presenters: Susan T. Wildau and Christopher W. Moore, CDR Associates (Collaborative Decision Resources), Boulder, CO 22 slide

On Mutualism, Models, and Masting: The Effects of Seed-Dispersing Animals on the plants they Disperse

© 2020 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society Species interactions are context dependent, in that their direction and magnitude can vary across ecological conditions. For seed dispersal interactions—especially interactions between plants and seed-caching animals—the direction of the interactions is often obscured because of seed mortality inherent in seed handling and the delayed effects of fitness benefits received by plants. It is, therefore, an open question in ecology to understand the ecological contexts under which seed dispersal interactions are facilitative, antagonistic or null. We review the fitness benefits of animal-mediated seed dispersal, extend a recently published model to include negative density-dependent effects, and review the feedback between seed production (with a focus on masting) and seed-caching animal populations. Negative density-dependent effects are pervasive and strongly affect the direction of plant-seed-disperser interactions, and including them into models will give a more accurate understanding of the direction of the interaction. Including negative density-dependent effects also makes the interpretation of interaction more mutualistic since seed dispersers decrease seed densities. Additionally, there is substantial interannual variability in seed production in most nut-producing plant species, and the lags between seed production and seed-disperser population sizes complicate and limit inferences made about the direction of interactions in any given short-term study. Synthesis. If we wish to know the direction of species interactions in real ecological communities, we need models that contain a minimum level of biological realism. For complex and long-term phenomena such as context-dependent species interactions we should embrace a multifaceted approach of short-term field research, long-term field research, simple models, and complex models to form a more robust understanding of the ecological problem of context dependency

City Best Practices to Improve Transit Operations and Safety

Public, fixed-route transit services most commonly operate on public streets. In addition, transit passengers must use sidewalks to access transit stops and stations. However, streets and sidewalks are under the jurisdiction of municipalities, not transit agencies. Various municipal policies, practices, and decisions affect transit operations, rider convenience, and passenger safety. Thus, these government entities have an important influence over the quality, safety, and convenience of transit services in their jurisdictions. This research identified municipal policies and practices that affect public transport providers’ ability to deliver transit services. They were found from a comprehensive literature review, interviews and discussions with five local transit agencies in the U.S., five public transportation experts and staff from five California cities. The city policies and practices identified fall into the following five categories: Infrastructure for buses, including bus lanes, signal treatments, curbside access; Infrastructure for pedestrians walking and bicycling to, and waiting at, transit stops and stations; Internal transportation planning policies and practices; Land development review policies; Regional and metropolitan planning organization (MPO) issues. The understanding, acknowledgment, and implementation of policies and practices identified in this report can help municipalities proactively work with local transit providers to more efficiently and effectively operate transit service and improve passenger comfort and safety on city streets

The Mismatch in Distributions of Vertebrates and the Plants that they Disperse

© 2018 The Authors Little is known about how mutualistic interactions affect the distribution of species richness on broad geographic scales. Because mutualism positively affects the fitness of all species involved in the interaction, one hypothesis is that the richness of species involved should be positively correlated across their range, especially for obligate relationships. Alternatively, if mutualisms involve multiple mutualistic partners, the distribution of mutualists should not necessarily be related, and patterns in species distributions might be more strongly correlated with environmental factors. In this study, we compared the distributions of plants and vertebrate animals involved in seed-dispersal mutualisms across the United States and Canada. We compiled geographic distributions of plants dispersed by frugivores and scatter-hoarding animals, and compared their distribution of richness to the distribution in disperser richness. We found that the distribution of animal dispersers shows a negative relationship to the distribution of the plants that they disperse, and this is true whether the plants dispersed by frugivores or scatter-hoarders are considered separately or combined. In fact, the mismatch in species richness between plants and the animals that disperse their seeds is dramatic, with plants species richness greatest in the in the eastern United States and the animal species richness greatest in the southwest United States. Environmental factors were corelated with the difference in the distribution of plants and their animal mutualists and likely are more important in the distribution of both plants and animals. This study is the first to describe the broad-scale distribution of seed-dispersing vertebrates and compare the distributions to the plants they disperse. With these data, we can now identify locations that warrant further study to understand the factors that influence the distribution of the plants and animals involved in these mutualisms