A survey of natural parasitism of mirid bugs by parasitoids on apples and pears in Norway

Mirid bugs are important pests in both integrated and organic fruit production. In a survey in 2006 the proportion of mirids parasitized by parasitoids was investigated in 18 Norwegian orchards. More than 50 beating samples were collected from apple and pear orchards under integrated and organic management in different areas of Norway. About 30% of nymphs of the most abundant mirid bug species, Lygocoris pabulinus, Ortholylus marginalis and Psallus ambiguus, were parasitized. Important factors for enhancing biological control in organic fruit production are discussed

Control methods against bugs (Hemiptera; Heteroptera) in organic apple and pear production

True bugs (Hemiptera; Heteroptera) are important pests in fruit production in Norway. In organic fruit pro-duction they may damage up to 40% of the crop. Several of the Heteropteran species attacking apple and pear are polyphagous, with many other hostplants than pome fruit. In organic production few control meth-ods are available against bugs. In this study we have tried a cultural control method (mowing of ground-cover) as well as spray applications of various biological insecticides against bugs. Spray application of azadirachtin (NeemAzal), rape oil and garlic extract (Ecoguard) were tested. Results indicate that the effect of mowing groundcover inside the orchard is variable and small. Applying NeemAzal reduced the number of bugs and damage. Oil and Ecoguard showed little effect in this study, however further testing is needed. Results from the first two years of the study will be discussed in relation to both cultural and direct control methods against bugs

Static Deflection Compensation of Multi-Link Flexible Manipulators Under Gravity

The static deflection compensation method of a planar multi-link flexible manipulator is proposed using the feedback from inertial sensors mounted at the tip of each link. The proposed compensation technique is validated experimentally using a high-precision laser tracker. The proposed strategy is experimentally verified using a three-link flexible manipulator. A strategy to compensate for the centripetal and tangential acceleration induced on the accelerometer mounted on the rotating link is proposed for correct inclination estimation. The improvement in the inclination estimation using the proposed compensation technique is verified both in simulation and experimental studies.publishedVersio

Combining checkpointing and data compression for large scale seismic inversion

Seismic inversion and imaging are adjoint-based optimization problems that processes up to terabytes of data, regularly exceeding the memory capacity of available computers. Data compression is an effective strategy to reduce this memory requirement by a certain factor, particularly if some loss in accuracy is acceptable. A popular alternative is checkpointing, where data is stored at selected points in time, and values at other times are recomputed as needed from the last stored state. This allows arbitrarily large adjoint computations with limited memory, at the cost of additional recomputations. In this paper we combine compression and checkpointing for the first time to compute a realistic seismic inversion. The combination of checkpointing and compression allows larger adjoint computations compared to using only compression, and reduces the recomputation overhead significantly compared to using only checkpointing

Towards self-verification in finite difference code generation

Code generation from domain-specific languages is becoming increasingly popular as a method to obtain optimised low-level code that performs well on a given platform and for a given problem instance. Ensuring the correctness of generated codes is crucial. At the same time, testing or manual inspection of the code is problematic, as the generated code can be complex and hard to read. Moreover, the generated code may change depending on the problem type, domain size, or target platform, making conventional code review or testing methods impractical. As a solution, we propose the integration of formal verification tools into the code generation process. We present a case study in which the CIVL verification tool is combined with the Devito finite difference framework that generates optimised stencil code for PDE solvers from symbolic equations. We show a selection of properties of the generated code that can be automatically specified and verified during the code generation process. Our approach allowed us to detect a previously unknown bug in the Devito code generation tool

Land cover type modulates the distribution of litter in a Nordic cultural landscape

Litter pollution is a global environmental problem that occurs in virtually all ecosystems. Scientific research on anthropogenic litter and its environmental impacts focusses predominantly on plastics and the marine environment. Little empirical knowledge exists about the distribution and ecological impacts of litter in terrestrial environments, where most litter is produced. To start closing that knowledge gap, we investigated the distribution of litter in a cultural landscape in central Norway and in relation to land cover types. We registered and collected litter in 110 survey plots that were randomly stratified across various land cover types. Our results show that land cover type modulates the occurrence, abundance, fragments size, and that litter is most present and abundant in or near land cover types associated with high human activities. Plastic was by far the most common litter material type, although the litter community (in terms of materials type) was not independent from land cover type. This knowledge can help to inform and optimize litter management and clean-up activities in terrestrial landscapes. How and to what extent the spatial structure of the litter community mediates ecological effects across various land cover types remains unknown to a large extent and warrants further study.publishedVersio

Scaling of Transport Coefficients of Porous Media under Compaction

Porous sediments in geological systems are exposed to stress by the above-laying mass and consequent compaction, which may be significantly nonuniform across the massif. We derive scaling laws for the compaction of sediments of similar geological origin. With these laws, we evaluate the dependence of the transport properties of a fluid-saturated porous medium (permeability, effective molecular diffusivity, hydrodynamic dispersion, electrical and thermal conductivities) on its porosity. In particular, we demonstrate that the assumption of a uniform geothermal gradient is not adequate for systems with nonuniform compaction and show the importance of the derived scaling laws for mathematical modelling of methane hydrate deposits; these deposits are believed to have potential for impact on global climate change and Glacial-Interglacial cycles.Comment: 6 pages, 2 figure

Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6-2.7A. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and Instrumentation 201