Localization Transition of Biased Random Walks on Random Networks

We study random walks on large random graphs that are biased towards a randomly chosen but fixed target node. We show that a critical bias strength b_c exists such that most walks find the target within a finite time when b>b_c. For b<b_c, a finite fraction of walks drifts off to infinity before hitting the target. The phase transition at b=b_c is second order, but finite size behavior is complex and does not obey the usual finite size scaling ansatz. By extending rigorous results for biased walks on Galton-Watson trees, we give the exact analytical value for b_c and verify it by large scale simulations.Comment: 4 pages, includes 4 figure

The approach to criticality in sandpiles

A popular theory of self-organized criticality relates the critical behavior of driven dissipative systems to that of systems with conservation. In particular, this theory predicts that the stationary density of the abelian sandpile model should be equal to the threshold density of the corresponding fixed-energy sandpile. This "density conjecture" has been proved for the underlying graph Z. We show (by simulation or by proof) that the density conjecture is false when the underlying graph is any of Z^2, the complete graph K_n, the Cayley tree, the ladder graph, the bracelet graph, or the flower graph. Driven dissipative sandpiles continue to evolve even after a constant fraction of the sand has been lost at the sink. These results cast doubt on the validity of using fixed-energy sandpiles to explore the critical behavior of the abelian sandpile model at stationarity.Comment: 30 pages, 8 figures, long version of arXiv:0912.320

Bonds - Income Bonds - Rights of Bondholders and Deductibility of Interest for Federal Income Tax Purposes

An income bond is an obligation of a corporation on which interest is payable only out of earnings, as distinguished from the ordinary corporate bond on which interest is a fixed charge regardless of earnings. Long regarded as a hybrid security which is to be issued only as a last resort, income bonds have grown surprisingly in popularity over the past two decades. It is the purpose of this comment to consider the historical background of income bonds, to make a comparative analysis of the bond indentures as they affect investors\u27 rights, and to consider the deductibility of income bond interest in determining taxable income for federal income tax purposes. A study of the twenty-three companies whose income bonds are currently listed on the New York Stock Exchange is the focal point for this comment, but the particular problems incident to unlisted bonds of small and closely-held corporations will also be considered

Raman Response in Doped Antiferromagnets

The resonant part of the $B_{1g}$ electronic Raman scattering response is calculated within the $t-J$ model on a planar lattice as a function of temperature and hole doping, using a finite-temperature diagonalization method for small systems. Results, directly applicable to experiments on cuprates, reveal on doping a very pronounced increase of the width of the two-magnon Raman peak, accompanied by a decrease of the total intensity. At the same time the peak position does not shift substantially in the underdoped regime.Comment: 11 pages revtex, 3 postscript figures. Minor corrections and changes from previous version, to be published in Phys. Rev.

Examining the relationship between measures of autistic traits and neural synchrony during movies in children with and without autism

Children who have been diagnosed with autism spectrum disorder (ASD) often show a marked deficit in measures of social cognition. In autistic adults, measures of social cognition have been shown to relate to differences in brain synchronization (as measured by fMRI) when individuals are processing naturalistic stimuli, such as movies. However, whether children who differ in their degree of autistic traits, with or without a diagnosis of ASD, differ in their neural responses to movies has not yet been investigated. In the current study, neural synchrony, measured using fMRI, was examined in three groups of children aged 7 to 12, who differed with respect to scores on a measure of autistic traits associated with social impairment and whether or not they had been diagnosed with ASD. While watching the movie ‘Despicable Me’, those diagnosed with ASD had significantly less neural synchrony in areas that have been previously shown to be associated with social cognition (e.g. areas related to ‘theory of mind’), and plot following (e.g. the lateral prefrontal cortex), than those who did not have an ASD diagnosis. In contrast, two groups who differed in their degree of autistic traits, but did not have a diagnosis of ASD, showed no significant differences in neural synchrony across the whole brain. These results shed some light on how autistic traits may contribute to an individual\u27s conscious experience of the world, and how, for children with ASD, that experience may differ markedly from that of those without ASD

Investigating red knot migration ecology along the Georgia coast: fall 2015 and spring 2013, 2015-16 season summaries

The rufa subspecies of the Red Knot (Calidris canutus) has declined significantly in the past 35 years, leading to federal listing (US Fish and Wildlife Service Federal Register Vol. 79 No. 238, 2014a) under the Endangered Species Act in the United States (16 U.S.C. 1531 et. seq) and Canada (COSEWIC 2007, SARA 2007). The determination of regional population estimates and identification of major stopover sites are considered to be the highest priority for the Georgia Department of Natural Resources State Wildlife Action Plan (2015), the Atlantic Flyway Shorebird Business Strategy (Winn et al. 2013), the US Shorebird Plan (Brown et al. 2001), the USFWS Red Knot Spotlight Species Action Plan (2010), and the Western Hemisphere Shorebird Reserve Network (WHSRN) Red Knot Conservation Plan for the Western Hemisphere (Niles et al. 2010a). The Georgia Department of Natural Resources State Wildlife Action Plan ranks the Red Knot as a high priority species (with state status of “Rare”) and ranks research of the Red Knot as one of the primary conservation actions needed within the state. A large percentage (3-6%) of Red Knots have been previously captured and tagged with unique 2 to 3 digits alpha-numeric bands. This marked population allows for mark-resight studies of migratory populations of Red Knots with no capturing involved. We detected a total of 43,686 Red Knots during daily surveys in spring 2016 along the Georgia Coast; of those, 10,029 were scanned for flags, and 1,255 individually banded Red Knots were resighted within the spring migrant population. A total of 158 marked to unmarked ratios were recorded during the field season, with an average of 3.8% of Red Knots individually marked over the course of the spring. The estimated superpopulation size for the spring 2016 season is 11,948 Red Knots (95% credible interval: 9,821 – 16,405). The mean Minimum-length-of-stay (MINLOS) for Red Knots staging in Georgia was 9.8day±11.1SD. A total of 3,805 Red Knots were detected on daily surveys during fall migration 2015; of those, 2,231 individuals were scanned for flags, and 140 individually banded Red Knots were resighted within that group. A total of 78 marked to unmarked ratios were recorded during the field season, with an average 3.4% of Red Knots banded. A total of 68 individuals were identified during the fall season, which was not enough data to analyze the population migrating through the Georgia Coast in fall 2015. We determined relative use along the Georgia Coast in spring and fall migration through a combination of aerial and ground based surveys. We created a GIS database of all encounters of Red Knots along the barrier Island chain, totaling 299 locations and 98,155 Red Knots mapped. The Georgia Coast is a major stopover area annually for rufa Red Knots in spring migration and in certain years in fall migration. The superpopulation utilizing the coast in fall migration can exceed 23,000 birds (Lyons et al. 2017 in press) and the estimates of spring migration superpopulation from this study ranges between 8,000 and 14,000 birds. The total estimated population of rufa Red Knots is 42,000 birds (Andres et al. 2012), suggesting that a high percentage of rufa knots are using the Georgia Coast in spring and in some years fall migration. There appears to be less variation in spring migration superpopulations between years than in fall migration, suggesting a more stable (but less abundant) food source for spring migrants

Mean value coordinates–based caricature and expression synthesis

We present a novel method for caricature synthesis based on mean value coordinates (MVC). Our method can be applied to any single frontal face image to learn a specified caricature face pair for frontal and 3D caricature synthesis. This technique only requires one or a small number of exemplar pairs and a natural frontal face image training set, while the system can transfer the style of the exemplar pair across individuals. Further exaggeration can be fulfilled in a controllable way. Our method is further applied to facial expression transfer, interpolation, and exaggeration, which are applications of expression editing. Additionally, we have extended our approach to 3D caricature synthesis based on the 3D version of MVC. With experiments we demonstrate that the transferred expressions are credible and the resulting caricatures can be characterized and recognized