Sound ranking algorithms for XML search

Ranking algorithms for XML should reflect the actual combined content and structure constraints of queries, while at the same time producing equal rankings for queries that are semantically equal. Ranking algorithms that produce different rankings for queries that are semantically equal are easily detected by tests on large databases: We call such algorithms not sound. We report the behavior of different approaches to ranking content-and-structure queries on pairs of queries for which we expect equal ranking results from the query semantics. We show that most of these approaches are not sound. Of the remaining approaches, only 3 adhere to the W3C XQuery Full-Text standard

The Effect of Compost Amendment on Ammonia-Oxidizing Microbial Community Structure in an Agricultural Soil

The effect of compost amendment on nitrification rates and ammonia-oxidizing microorganisms in an agricultural soil was examined. Four different rates from 11.2 to 89.6 Mg compost ha-1 of partially composted dairy manure was applied annually from 2000 to 2003 and again in 2005 to 32 plots on a Dormont silt loam that was shifted from long term pasture to crop cultivation. An additional 8 plots were not amended with compost and served as negative controls. Except for lime in the initial year of the experiment, no other fertilizer was used on these plots. Soil physical, chemical, and biochemical measurements were taken from 4 randomly chosen replicate plots of each treatment. Additionally, T-RFLP was used to fingerprint the community of bacteria and archaea responsible for the process of ammonia oxidation using the amoA gene. Extracted DNA concentration and potentially mineralizable nitrogen both significantly increased with increasing rates of compost amendment. There were significant positive correlations between potential ammonia oxidation and potentially mineralizable nitrogen, extracted DNA concentration and potentially mineralizable nitrogen, and extracted DNA and microbial biomass carbon in these plots. Many relationships were stronger when only the three lowest treatments were analyzed. Diversity measures generally did not show strong relationships with compost amendment rates, but there were significant correlations with biochemical variables. Ammonia-oxidizing archaeal (AOA) Shannon diversity and richness negatively correlated with the microbial biomass carbon pool size. Ammonia-oxidizing bacterial (AOB) Shannon evenness and Smith and Wilson evenness negatively correlated with potentially mineralizable nitrogen rate. Analysis of similarity showed that AOB communities with similar rates of nitrogen mineralization were more similar in community composition than would be predicted by chance alone. Nonmetric multidimensional scaling analysis showed that both AOA and AOB communities had nonlinear differences in community similarity based on compost amendment rate. AOA community similarity had a linear relationship with microbial biomass carbon and a nonlinear relationship with potentially mineralizable nitrogen. AOB community similarity had a linear relationship with both potentially mineralizable nitrogen and potential ammonia oxidation, and a weak nonlinear relationship with microbial biomass carbon. Linearity suggests a direct relationship between the two variables, while nonlinearity suggests an indirect relationship between the two variables. This evidence suggests that there is a difference in the ecological niches of the AOA and AOB, with AOB primarily responsible for ammonia oxidation in these plots

Bayesian Renormalization

In this note we present a fully information theoretic approach to renormalization inspired by Bayesian statistical inference, which we refer to as Bayesian Renormalization. The main insight of Bayesian Renormalization is that the Fisher metric defines a correlation length that plays the role of an emergent RG scale quantifying the distinguishability between nearby points in the space of probability distributions. This RG scale can be interpreted as a proxy for the maximum number of unique observations that can be made about a given system during a statistical inference experiment. The role of the Bayesian Renormalization scheme is subsequently to prepare an effective model for a given system up to a precision which is bounded by the aforementioned scale. In applications of Bayesian Renormalization to physical systems, the emergent information theoretic scale is naturally identified with the maximum energy that can be probed by current experimental apparatus, and thus Bayesian Renormalization coincides with ordinary renormalization. However, Bayesian Renormalization is sufficiently general to apply even in circumstances in which an immediate physical scale is absent, and thus provides an ideal approach to renormalization in data science contexts. To this end, we provide insight into how the Bayesian Renormalization scheme relates to existing methods for data compression and data generation such as the information bottleneck and the diffusion learning paradigm.Comment: 20 pages, no figures. V2: Citation format fixed, references adde

Nonconscious Motivational Influences on Cognitive Processes in Addictive Behaviors

This chapter presents the motivational and goal theory of current concerns in relation to addiction and choice. A current concern is an individual’s motivational state from the point of becoming committed to pursuing a particular goal until the goal is reached or the pursuit is relinquished. During this time, the current concern guides the person’s cognitive processes, including attention, memory, thoughts, and dreams. What is true of goals in general is true of the goal of drinking alcohol or using another addictive substance. We hold that the decision to use a substance is voluntary; thus, the choice to use is subject to the person’s conscious control. Nevertheless, implicit processes influence the decision. One of these processes is addiction-related attentional bias. We describe (1) the research on attentional bias and (2) interventions for helping drinkers overcome the attentional and motivational influences on their addictive behavior

BRST Cohomology is Lie Algebroid Cohomology

In this paper we demonstrate that the exterior algebra of an Atiyah Lie algebroid generalizes the familiar notions of the physicist's BRST complex. To reach this conclusion, we develop a general picture of Lie algebroid morphisms as commutative diagrams between algebroids preserving the geometric structure encoded in their brackets. We illustrate that a necessary and sufficient condition for such a diagram to define a morphism is that the two algebroids possess gauge-equivalent connections. This observation indicates that the set of Lie algebroid morphisms should be regarded as equivalent to the set of local diffeomorphisms and gauge transformations. Moreover, a Lie algebroid morphism being a chain map in the exterior algebra sense ensures that morphic algebroids are cohomologically equivalent. The Atiyah Lie algebroids derived from principal bundles with common base manifolds and structure groups may therefore be divided into equivalence classes of morphic algebroids. Each equivalence class possesses a representative which we refer to as the trivialized Lie algebroid, and we show that the exterior algebra of the trivialized algebroid gives rise to the BRST complex. We conclude by illustrating the usefulness of Lie algebroid cohomology in computing quantum anomalies. In particular, we pay close attention to the fact that the geometric intuition afforded by the Lie algebroid (which was absent in the naive BRST complex) provides hints of a deeper picture that simultaneously geometrizes the consistent and covariant forms of the anomaly. In the algebroid construction, the difference between the consistent and covariant anomalies is simply a different choice of basis.Comment: 24 pages, 1 figure, LaTe

Soliton stripes in two-dimensional nonlinear photonic lattices

We study experimentally the interaction of a soliton with a nonlinear lattice. We observe the formation of a novel type of composite soliton created by strong coupling of mutually incoherent periodic and localized beam components. By imposing an initial transverse momentum on the soliton stripe, we observe the effect of lattice compression and deformation.Comment: three pages, four figure