Bivariate stochastic modeling of functional response with natural mortality

A correction due to Abbott (1925) is the standard method of dealing with control mortality in insect bioassay to estimate the mortality of an insect conditional on control mortality not having occurred. In this article a bivariate stochastic process for overall mortality is developed in which natural mortality and predation are jointly modeled to take account of the competing-risks associated with prey loss. The total mortality estimate from this model is essentially identical with that from more classical modeling. However, when predation loss is estimated in the absence of control mortality the results are somewhat different, with the estimate from the bivariate model being lower than that from using Abbott’s formula in conjunction with the classical model. It is argued that overdispersion in observed mortality data corresponds to correlated outcomes (death or survival) for the prey initially present, while Abbott’s correction relies implicitly on independence

Benefits of European climate policies for mercury air pollution

This paper presents the methodology and results of impact assessment of renewable energy policies on atmospheric emissions of mercury in Europe. The modeling exercise described here involves an interaction of several models. First, a set of energy scenarios has been developed with the REMix (Renewable Energy Mix) model that simulates different levels of penetration of renewable energies in the European power sector. The energy scenarios were input to the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) model, which prepared projections of mercury releases to the atmosphere through 2050, based on the current air pollution control policies in each country. Data on mercury emissions from individual sectors were subsequently disaggregated to a fine spatial resolution using various proxy parameters. Finally, the dispersion of mercury in the atmosphere was computed by the chemistry transport model, implemented to the air quality system, Polyphemus. The simulations provided information on changes in concentrations and depositions of various forms of mercury over Europe. Scenarios that simulate a substantial expansion of renewable energies within the power sector indicate extensive co-benefits for mercury abatement, due to the restructuring of the energy system and changes in the fuel mix. The potential for mercury reductions in Europe depends on the rate of fuel switches and renewable technology deployment, but is also influenced by the stringency and timing of the air quality measures. The overall scope for co-benefits is therefore higher in regions relying on coal combustion as a major energy source

Pheromone traps for monitoring Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) in the presence of mating disruption

High-dose pheromone lures have proved useful for monitoring some lepidopteran pests in the presence of mating disruption, but not others. We performed experiments in commercial and pilot scale facilities to examine the effect of pheromone dose on detection of Indianmeal moth, Plodia interpunctella (Lepidoptera: Pyralidae), in the presence of mating disruption. When P. interpunctella males were released into 1000 m3 rooms containing traps baited with 0, 1, or 10 mg (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac), traps containing 10 mg captured more than those baited with 1 mg in both the presence and absence of mating disruption. Traps baited with 1 mg captured fewer males in the presence of mating disruption than in its absence, but the opposite was observed with traps baited with 10 mg. When males released into 73 m3 rooms were exposed sequentially to blank traps, traps baited with unmated females, and traps baited with 0.1 mg and then 1.0 mg Z9, E12-14:Ac in the presence or absence of mating disruption, 92% of trapped males were captured in female-baited traps in the absence of mating disruption, whereas in the presence of mating disruption 72% of males captured were caught in synthetic pheromone traps. These data suggest that pheromone lures can be used for monitoring P. interpunctella in the presence of mating disruption. Implications of these data for mass trapping are also discussed. Keywords: Plodia interpunctella, Mating disruption, Monitoring, Pheromone lures, Mass trappin

The shape and erosion of pebbles

The shapes of flat pebbles may be characterized in terms of the statistical distribution of curvatures measured along their contours. We illustrate this new method for clay pebbles eroded in a controlled laboratory apparatus, and also for naturally-occurring rip-up clasts formed and eroded in the Mont St.-Michel bay. We find that the curvature distribution allows finer discrimination than traditional measures of aspect ratios. Furthermore, it connects to the microscopic action of erosion processes that are typically faster at protruding regions of high curvature. We discuss in detail how the curvature may be reliable deduced from digital photographs.Comment: 10 pages, 11 figure

A LRRK2-Dependent EndophilinA Phosphoswitch Is Critical for Macroautophagy at Presynaptic Terminals.

Synapses are often far from the soma and independently cope with proteopathic stress induced by intense neuronal activity. However, how presynaptic compartments turn over proteins is poorly understood. We show that the synapse-enriched protein EndophilinA, thus far studied for its role in endocytosis, induces macroautophagy at presynaptic terminals. We find that EndophilinA executes this unexpected function at least partly independent of its role in synaptic vesicle endocytosis. EndophilinA-induced macroautophagy is activated when the kinase LRRK2 phosphorylates the EndophilinA-BAR domain and is blocked in animals where EndophilinA cannot be phosphorylated. EndophilinA-phosphorylation promotes the formation of highly curved membranes, and reconstitution experiments show these curved membranes serve as docking stations for autophagic factors, including Atg3. Functionally, deregulation of the EndophilinA phosphorylation state accelerates activity-induced neurodegeneration. Given that EndophilinA is connected to at least three Parkinson's disease genes (LRRK2, Parkin and Synaptojanin), dysfunction of EndophilinA-dependent synaptic macroautophagy may be common in this disorder