The influence of tree age and microhabitat quality on the occurrence of crustose lichens associated with old oaks

Questions: How do tree age, microhabitat characteristics and epiphytic competitors affect the occurrence of crustose lichens associated with old oaks? How do microhabitat characteristics and microclimate affect the cover of competitors (bryophytes and macrolichens)? How do microhabitat characteristics cor¬relate with microclimatic variables? Location: Southeast Sweden. Methods: Eight crustose lichen species were surveyed on 165 Quercus robur trees, 17-478 years old, at three study sites. The occurrence patterns of these species were examined at two spatial scales: among trees and within trees. Occurrence patterns within trees were examined in 10 cm × 10 cm plots at all four cardinal aspects at different heights from 0.5 to 4.5 m above the ground. Results: At the tree level, age-related factors were the most important predictors of species occurrence. All species were more frequent on trees > 100 years than on younger trees. At the plot level, the frequency of occurrence increased with increasing bark crevice depth. The frequencies of all study species de¬creased with increasing cover of bryophytes. Bryophytes were in turn more frequent in plots that were exposed to rainwater and showed a low evaporation rate. Patches most exposed to rainwater were directed upwards, and the lowest evaporation rates occurred on the northern side of the trunks. Conclusions: For many crustose lichens the association with old oak trees seems at least partly to depend on their preference for the deep bark crevices that only occur on old trees. Trees represent epiphyte habitat patches that differ in size due to within-tree variability in habitat quality, such as bark crevice depth and microclimate. This study shows that variability at a finer scale, within habitat patches, contribute to explain species occurrence patterns at habitat patch level

Expansion of kk-Schur functions for maximal kk-rectangles within the affine nilCoxeter algebra

We give several explicit combinatorial formulas for the expansion of k-Schur functions indexed by maximal rectangles in terms of the standard basis of the affine nilCoxeter algebra. Using our result, we also show a commutation relation of k-Schur functions corresponding to rectangles with the generators of the affine nilCoxeter algebra.Comment: to appear in Journal of Combinatorics, 28 page

Leveling the Playing Field: Applying Federal Corporate Charging Considerations to Individuals

The American prison system is grappling with a well-publicized carceral crisis. In the words of former U.S. Attorney General Eric Holder, “too many Americans go to too many prisons for far too long, and for no truly good law enforcement reason.” And, as a result of developments in federal law over the past few decades, the power of federal prosecutors to decide when and how to charge individuals with crimes is crucial to when and how American citizens go to prison. Many ideas have been proposed to revise prosecutorial discretionary powers, but few have been heeded by the Department of Justice (DOJ). However, this Note posits that the DOJ has already paved the way to enhanced guidance for federal prosecutors when charging individuals with crimes. This is because the DOJ’s prosecutorial guidance for charging corporations with federal crimes is more robust than the guidance for charging individuals. In particular, a discussion on collateral consequences is included in the corporate charging guidance, yet lacking in the individual charging guidance. This enhanced corporate guidance has had the purposeful impact of curtailing the prosecution of corporate crime. This Note argues that a similar discussion of collateral consequences in the individual charging guidance could have important and far-reaching effects on the federal criminal regime. Perhaps more importantly, such a discussion could remedy some of the unfairness presented by the current system in which federal prosecutors are guided to consider a superior set of factors before charging corporations with crimes

Graph Convolutional Matrix Completion

We consider matrix completion for recommender systems from the point of view of link prediction on graphs. Interaction data such as movie ratings can be represented by a bipartite user-item graph with labeled edges denoting observed ratings. Building on recent progress in deep learning on graph-structured data, we propose a graph auto-encoder framework based on differentiable message passing on the bipartite interaction graph. Our model shows competitive performance on standard collaborative filtering benchmarks. In settings where complimentary feature information or structured data such as a social network is available, our framework outperforms recent state-of-the-art methods.Comment: 9 pages, 3 figures, updated with additional experimental evaluatio

Religious Conservatives and the Death Penalty

With the increased fervor surrounding the death penalty, many religious sects have re-examined their position on this issue. New statistics concerning possible discrimination in the application of the death penalty prompted several religious groups to call for a moratorium on the death penalty. In this Essay, Professor Thomas C. Berg examines how religious conservatives, especially Roman Catholics and evangelical Protestants, have dealt with the recent concerns over the death penalty. Part I of the Essay documents how Roman Catholics and evangelical Protestants traditionally approach the death penalty. In this section, Professor Berg concludes that critics of the death penalty can use theological arguments, as well as practical concerns about the death penalty, to persuade both groups to oppose the death penalty. Part II analyzes the particular theological arguments and practical concerns that will be most effective in persuading religious conservatives to oppose the death penalty

A Determination of Interface Free Energies

We determine the interface free energy $F_{o.d.}$ between disordered and ordered phases in the q=10 and q=20 2-d Potts models using the results of multicanonical Monte Carlo simulations on $L^2$ lattices, and suitable finite volume estimators. Our results, when extrapolated to the infinite volume limit, agree to high precision with recent analytical calculations. At the transition point $\beta_t$ the probability distribution function of the energy exhibits two maxima. Their locations have $1/L^2$ corrections, in contradiction with claims of $1/L$ behavior made in the literature. Our data show a flat region inbetween the two maxima which characterizes two domain configurations.Comment: Submited to Nuclear Physics B (FS) Latex file, 24 pages, 11 PostScript figures. Saclay preprint SPhT-93/6

Quantifying microbubble clustering in turbulent flow from single-point measurements

Single-point hot-wire measurements in the bulk of a turbulent channel have been performed in order to detect and quantify the phenomenon of preferential bubble accumulation. We show that statistical analysis of the bubble-probe colliding-times series can give a robust method for investigation of clustering in the bulk regions of a turbulent flow where, due to the opacity of the flow, no imaging technique can be employed. We demonstrate that micro-bubbles (radius R_0 ~ 0.1 mm) in a developed turbulent flow, where the Kolmogorov length-scale is, eta ~ R_0, display preferential concentration in small scale structures with a typical statistical signature ranging from the dissipative range, O(eta), up to the low inertial range, O(100 eta). A comparison with Eulerian-Lagrangian numeri- cal simulations is also presented to further support our proposed way to characterize clustering from temporal time series at a fixed position.Comment: 7 pages, 4 figure