Dynamics of latent voters

We study the effect of latency on binary-choice opinion formation models. Latency is introduced into the models as an additional dynamic rule: after a voter changes its opinion, it enters a waiting period of stochastic length where no further changes take place. We first focus on the voter model and show that as a result of introducing latency, the average magnetization is not conserved, and the system is driven toward zero magnetization, independently of initial conditions. The model is studied analytically in the mean-field case and by simulations in one dimension. We also address the behavior of the Majority Rule model with added latency, and show that the competition between imitation and latency leads to a rich phenomenology

Decoherence and entropy of primordial fluctuations. I: Formalism and interpretation

We propose an operational definition of the entropy of cosmological perturbations based on a truncation of the hierarchy of Green functions. The value of the entropy is unambiguous despite gauge invariance and the renormalization procedure. At the first level of truncation, the reduced density matrices are Gaussian and the entropy is the only intrinsic quantity. In this case, the quantum-to-classical transition concerns the entanglement of modes of opposite wave-vectors, and the threshold of classicality is that of separability. The relations to other criteria of classicality are established. We explain why, during inflation, most of these criteria are not intrinsic. We complete our analysis by showing that all reduced density matrices can be written as statistical mixtures of minimal states, the squeezed properties of which are less constrained as the entropy increases. Pointer states therefore appear not to be relevant to the discussion. The entropy is calculated for various models in paper II.Comment: 23 page

The role of cracks in the nonlinear interaction of a P-wave with an S-wave

Cracks play a key role in our ability to produce oil and gas, from micro-scalecracks that enable permeability in tight formations to faults and fractures that compartmentalize reservoirs; our ability to sense and understand them remotely is thus of key importance. We explore the role that cracks play in the nonlinear interaction of propagating waves. We present a laboratory experiment in which a strong S-wave slightly changes the velocity of a lower amplitude P-wave, and use a rock sample with aligned fractures to demonstrate that this signal is strongly dependent on fracture orientation. We build on the linear slip theory to show that the propagating S-wave is indeed able to open the cracks that the P-wave velocity will be most sensitive to. This gives firm, direct evidence that cracks are a controlling factor in the nonlinear elastic properties of rocks, and opens up the possibility of using such signals to remotely map fracture orientations

10/16/1947 Letter from Les Attractions Artistiques

Letter from P. D. Renaud of Les Attractions Artistiques in Montreal to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-1947-10-12/1011/thumbnail.jp

12/17/1947 Western Union Telegram

A Western Union Telegram from P. D. Renaud of Les Attractions Artistiques to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-1947-10-12/1048/thumbnail.jp

Chesapeake Coastal Community Flood Vulnerability--Prediction and Verification

Fast moving hurricanes and stationary nor’easters have resulted in significant flood damage in Chesapeake tidewater communities. The Chesapeake Bay region is one of A m erica’s most vulnerable regions with respect to sea-level rise, which will only increase storm surge impacts over upcoming decades. While the general trends are well documented, there is limited information relevant to specific communities’ relative flood risk and response. The dearth o f data is especially troublesome given the lengthy period o f time generally needed for communities to plan and implement adaptive action. This study contributes to the regional understanding of flood and sea-level rise vulnerability by applying physical, social, and combined vulnerability indices to tidally influenced localities along the Chesapeake Bay. Unlike other combinations of physical and socioeconomic data, the physical vulnerability index for this study is calculated at a scale that can directly link into social vulnerability index information at local and regional levels. The research also considers the distribution of coastal natural capital (in the form o f marshes and forests) alongside these indices at comparable scales. By calculating the indices for conditions o f the early 2000s, this study also tested their predictive value against Hurricane Isabel, a landmark 2003 storm that flooded areas across the region. Systematic verification “hindcasts” o f past events are relatively rare for vulnerability index evaluation. By attempting to establish connections between real flooding data, socioeconomic activity, and vulnerability indices, this study questions whether theoretical vulnerability indices work as true proxies for real world conditions. The results question the true utility o f these indices by showing limited relationships between vulnerability and changes in community socio-economic activity. The research also emphasizes the need for more data collection and consideration in order to better comprehensively understand coastal flood impacts and their management implications

Single-hole transistor in p-type GaAs/AlGaAs heterostructures

A single-hole transistor is patterned in a p-type, C-doped GaAs/AlGaAs heterostructure by AFM oxidation lithography. Clear Coulomb blockade resonances have been observed at T=300 mK. A charging energy of ~ 1.5 meV is extracted from Coulomb diamond measurements, in agreement with the lithographic dimensions of the dot. The absence of excited states in Coulomb diamond measurements, as well as the temperature dependence of Coulomb peak heights indicate that the dot is in the multi-level transport regime. Fluctuations in peak spacings larger than the estimated mean single-particle level spacing are observed.Comment: 4 pages, 5 figure

South-West extension of the hard X-ray emission from the Coma cluster

We explore the morphology of hard (18-30 keV) X-ray emission from the Coma cluster of galaxies. We analyze a deep (1.1 Ms) observation of the Coma cluster with the ISGRI imager on board the \emph{INTEGRAL} satellite. We show that the source extension in the North-East to South-West (SW) direction ($\sim 17'$) significantly exceeds the size of the point spread function of ISGRI, and that the centroid of the image of the source in the 18-30 keV band is displaced in the SW direction compared to the centroid in the 1-10 keV band. To test the nature of the SW extension we fit the data assuming different models of source morphology. The best fit is achieved with a diffuse source of elliptical shape, although an acceptable fit can be achieved assuming an additional point source SW of the cluster core. In the case of an elliptical source, the direction of extension of the source coincides with the direction toward the subcluster falling onto the Coma cluster. If the SW excess is due to the presence of a point source with a hard spectrum, we show that there is no obvious X-ray counterpart for this additional source, and that the closest X-ray source is the quasar EXO 1256+281, which is located $6.1'$ from the centroid of the excess. The observed morphology of the hard X-ray emission clarifies the nature of the hard X-ray "excess" emission from the Coma cluster, which is due to the presence of an extended hard X-ray source SW of the cluster core.Comment: 7pages, 10 figure