Soil Viruses: A New Hope.

As abundant members of microbial communities, viruses impact microbial mortality, carbon and nutrient cycling, and food web dynamics. Although most of our information about viral communities comes from marine systems, evidence is mounting to suggest that viruses are similarly important in soil. Here I outline soil viral metagenomic approaches and the current state of soil viral ecology as a field, and then I highlight existing knowledge gaps that we can begin to fill. We are poised to elucidate soil viral contributions to terrestrial ecosystem processes, considering: the full suite of potential hosts across trophic scales, the ecological impacts of different viral replication strategies, links to economically relevant outcomes like crop productivity, and measurable in situ virus-host population dynamics across spatiotemporal scales and environmental conditions. Soon, we will learn how soil viruses contribute to food webs linked to organic matter decomposition, carbon and nutrient cycling, greenhouse gas emissions, and agricultural productivity

Genes, geología y biodiversidad: diversidad de la fauna y flora de la isla de Gran Canaria

High levels of floral and faunal diversity in the Canary Islands have attracted much attention to the archipelago for both evolutionary and ecological study. Among the processes that have influenced the development of this diversity, the volcanic history of each individual island must have played a pivotal role. The central island of Gran Canaria has a long geological history of approximately 15 million years that was interrupted by violent volcanism between 5.5 and 3 million years ago. Volcanic activity is thought to have been so great as to have made all plant and animal life virtually extinct, with survival being limited to some coastal species. The implication from this is that the higher altitude laurel forest and pine woods environments must have been re–established following the dramatic volcanic period. This paper reviews the evidence for this using recent molecular phylogenetic data for a number of plant and animal groups on the island of Gran Canaria, and concludes that there is general support for the hypotheses that the forest environments of Gran Canaria post–date the Roque Nublo eruptive period.La extensa diversidad de la flora y fauna de las Islas Canarias ha convertido el archipiélago en un centro de especial interés para los estudios sobre evolución y ecología. De entre los procesos que han influido en el desarrollo de esta diversidad, cabe destacar el importante papel que ha desempeñado la historia volcánica de cada una de las islas. La isla principal del archipiélago, Gran Canaria, tiene una larga historia geológica de aproximadamente unos 15 millones de años, que fue interrumpida por un violento volcanismo que tuvo lugar hace entre 5,5 y 3 millones de años. Se considera que la actividad volcánica fue de tal magnitud, que prácticamente extinguió toda la vida vegetal y animal de las islas, a excepción de unas pocas especies costeras que lograron sobrevivir. De ello puede deducirse que los entornos de mayor altitud, como los bosques de laureles y pinos, seguramente se reestablecieron tras el dramático período volcánico antes mencionado. En este trabajo, se revisa la evidencia de ello mediante el análisis de datos filogénicos moleculares recientes de una serie de grupos de plantas y animales de la isla de Gran Canaria, y se demuestra la validez general de la hipótesis que sostiene que los entornos forestales de Gran Canaria son posteriores al ciclo eruptivo de Roque Nublo

The JPL MSAT mobile laboratory and the pilot field experiments

A Mobile Laboratory/Propagation Measurement Van (PMV) was developed to support the field experiments of the Mobile Satellite Experiment (MSAT-X) Project. This van was designed to provide flexibility, self-sufficiency and data acquisition to allow for both measurement of equipment performance and the mobile environment. The design philosophy and implementation of the PMV are described. The Pilot Field Experiments and an overall description of the three experiments in which the PMV was used are described

Judicial Citation to Legislative History: Contextual Theory and Empirical Analysis

Judge Leventhal famously described the invocation of legislative history as the equivalent of entering a crowded cocktail party and looking over the heads of the guests for one\u27s friends. The volume of legislative history is so great and varied, some contend, that judges cite it selectively to advance their policy agendas. In this article, we employ positive political and contextual theories of judicial behavior to examine how judges use legislative history. We consider whether opinion-writing judges, as Judge Leventhal might suggest, cite legislative history from legislators who share the same political-ideological perspective as the opinion-writing judge? Or do judges make such choices in a broader context than Judge Levanthal\u27s statement suggests. We posit that an opinion writing judge would cite legislative statements supporting an outcome preferred by the opinion-writing judge, when such statements come from legislators who share the same political-ideological perspective as the opinion-writing judge\u27s colleagues or superiors. This should be so regardless of whether the cited legislator shares the broader perspectives of the opinion-writing judge himself. Put in Leventhal\u27s terms, instead of looking for their own ideological friends, judges look over the heads of the guests for the legislative friends of the judge\u27s colleagues on the bench (or superiors on higher benches). We test this approach with court opinion data gathered from LEXIS and find evidence of hierarchy (high court oversight) and panel (co-members on a court) effects in citation to legislative history, effects that appear related to the political-ideological identification of judges who review or are co-members on a panel of the authoring judge. Specifically, we find that the higher the proportion of Republicans in the reviewing court or sitting on the same three-judge panel, the higher the proportion of legislative history cites that will be to Republican legislators, independent of the political orientation of the authoring judge

Judicial Citation to Legislative History: Contextual Theory and Empirical Analysis

Judge Leventhal famously described the invocation of legislative history as the equivalent of entering a crowded cocktail party and looking over the heads of the guests for one\u27s friends. The volume of legislative history is so great and varied, some contend, that judges cite it selectively to advance their policy agendas. In this article, we employ positive political and contextual theories of judicial behavior to examine how judges use legislative history. We consider whether opinion-writing judges, as Judge Leventhal might suggest, cite legislative history from legislators who share the same political-ideological perspective as the opinion-writing judge? Or do judges make such choices in a broader context than Judge Levanthal\u27s statement suggests. We posit that an opinion writing judge would cite legislative statements supporting an outcome preferred by the opinion-writing judge, when such statements come from legislators who share the same political-ideological perspective as the opinion-writing judge\u27s colleagues or superiors. This should be so regardless of whether the cited legislator shares the broader perspectives of the opinion-writing judge himself. Put in Leventhal\u27s terms, instead of looking for their own ideological friends, judges look over the heads of the guests for the legislative friends of the judge\u27s colleagues on the bench (or superiors on higher benches). We test this approach with court opinion data gathered from LEXIS and find evidence of hierarchy (high court oversight) and panel (co-members on a court) effects in citation to legislative history, effects that appear related to the political-ideological identification of judges who review or are co-members on a panel of the authoring judge. Specifically, we find that the higher the proportion of Republicans in the reviewing court or sitting on the same three-judge panel, the higher the proportion of legislative history cites that will be to Republican legislators, independent of the political orientation of the authoring judge

Parameterized Model-Checking for Timed-Systems with Conjunctive Guards (Extended Version)

In this work we extend the Emerson and Kahlon's cutoff theorems for process skeletons with conjunctive guards to Parameterized Networks of Timed Automata, i.e. systems obtained by an \emph{apriori} unknown number of Timed Automata instantiated from a finite set $U_1, \dots, U_n$ of Timed Automata templates. In this way we aim at giving a tool to universally verify software systems where an unknown number of software components (i.e. processes) interact with continuous time temporal constraints. It is often the case, indeed, that distributed algorithms show an heterogeneous nature, combining dynamic aspects with real-time aspects. In the paper we will also show how to model check a protocol that uses special variables storing identifiers of the participating processes (i.e. PIDs) in Timed Automata with conjunctive guards. This is non-trivial, since solutions to the parameterized verification problem often relies on the processes to be symmetric, i.e. indistinguishable. On the other side, many popular distributed algorithms make use of PIDs and thus cannot directly apply those solutions

Local stability analysis and eigenvalue sensitivity of reacting bluff-body wakes

This paper presents an experimental and theoretical investigation of high-Reynolds-number low-density reacting wakes near a hydrodynamic Hopf bifurcation. This configuration is applicable to the wake flows that are commonly used to stabilize flames in high-velocity flows. First, an experimental study is conducted to measure the limit-cycle oscillation of this reacting bluff-body wake. The experiment is repeated while independently varying the bluff-body lip velocity and the density ratio across the flame. In all cases, the wake exhibits a sinuous oscillation. Linear stability analysis is performed on the measured time-averaged velocity and density fields. In the first stage of this analysis, a local spatiotemporal stability analysis is performed on the measured time-averaged velocity and density fields. The stability analysis results are compared to the experimental measurement and demonstrate that the local stability analysis correctly captures the influence of the lip-velocity and density-ratio parameters on the sinuous mode. In the second stage of the analysis, the linear direct and adjoint global modes are estimated by combining the local results. The sensitivity of the eigenvalue to changes in intrinsic feedback mechanisms is found by combining the direct and adjoint global modes. This is referred to as the eigenvalue sensitivity throughout the paper for reasons of brevity. The predicted global mode frequency is consistently within 10 % of the measured value, and the linear global mode shape closely resembles the measured nonlinear oscillations. The adjoint global mode reveals that the oscillation is strongly sensitive to open-loop forcing in the shear layers. The eigenvalue sensitivity identifies a wavemaker in the recirculation zone of the wake. A parametric study shows that these regions change little when the density ratio and lip velocity change. In the third stage of the analysis, the stability analysis is repeated for the varicose hydrodynamic mode. Although not physically observed in this unforced flow, the varicose mode can lock into longitudinal acoustic waves and cause thermoacoustic oscillations to occur. The paper shows that the local stability analysis successfully predicts the global hydrodynamic stability characteristics of this flow and shows that experimental data can be post-processed with this method in order to identify the wavemaker regions and the regions that are most sensitive to external forcing, for example from acoustic waves.Matthew Juniper acknowledges the financial support of the European Research Council under grant 2590620. Tim Lieuwen acknowledges the support of the University Turbine Systems Research (contract #DE-FC21-92MC29061) program under contract monitor Dr. Mark Freeman, and the Air Force Office of Scientific Research (contract #FA9550- 12-1-0107/RC657), under contract monitor Dr. Chiping Lee.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/jfm.2015.72