Optimisation of patch distribution strategies for AMR applications

As core counts increase in the world's most powerful supercomputers, applications are becoming limited not only by computational power, but also by data availability. In the race to exascale, efficient and effective communication policies are key to achieving optimal application performance. Applications using adaptive mesh refinement (AMR) trade off communication for computational load balancing, to enable the focused computation of specific areas of interest. This class of application is particularly susceptible to the communication performance of the underlying architectures, and are inherently difficult to scale efficiently. In this paper we present a study of the effect of patch distribution strategies on the scalability of an AMR code. We demonstrate the significance of patch placement on communication overheads, and by balancing the computation and communication costs of patches, we develop a scheme to optimise performance of a specific, industry-strength, benchmark application

Major Facilitator Superfamily Domain-Containing Protein 2a (MFSD2A) Has Roles in Body Growth, Motor Function, and Lipid Metabolism

10.1371/journal.pone.0050629PLoS ONE711

Bedrijfsuitkomsten in de Nederlandse particuliere bosbouw over 2007

De gemiddelde opbrengst van het particuliere bosbedrijf steeg van bijna 260 euro in 2006 naar ruim 300 euro per ha in 2007. De prijzen voor hout is voor het tweede achtereenvolgend jaar drastisch toegenomen. Het inkomen van grotere bedrijven steeg naar 90 euro per hectar

Solar Stereoscopy with STEREO/EUVI A and B spacecraft from small (6 deg) to large (170 deg) spacecraft separation angles

We performed for the first time stereoscopic triangulation of coronal loops in active regions over the entire range of spacecraft separation angles ($\alpha_{sep}\approx 6^\circ, 43^\circ, 89^\circ, 127^\circ$, and $170^\circ$). The accuracy of stereoscopic correlation depends mostly on the viewing angle with respect to the solar surface for each spacecraft, which affects the stereoscopic correspondence identification of loops in image pairs. From a simple theoretical model we predict an optimum range of $\alpha_{sep} \approx 22^\circ-125^\circ$, which is also experimentally confirmed. The best accuracy is generally obtained when an active region passes the central meridian (viewed from Earth), which yields a symmetric view for both STEREO spacecraft and causes minimum horizontal foreshortening. For the extended angular range of $\alpha_{sep}\approx 6^\circ-127^{\circ}$ we find a mean 3D misalignment angle of $\mu_{PF} \approx 21^\circ-39^\circ$ of stereoscopically triangulated loops with magnetic potential field models, and $\mu_{FFF} \approx 15^\circ-21^\circ$ for a force-free field model, which is partly caused by stereoscopic uncertainties $\mu_{SE} \approx 9^\circ$. We predict optimum conditions for solar stereoscopy during the time intervals of 2012--2014, 2016--2017, and 2021--2023.Comment: Solar Physics, (in press), 22 pages, 9 figure

Calculation of electron emission from a tantalum foil irradiated by 100-kV and 50-kV x-rays

Two Monte Carlo programs, XITRAN and XMTRAN, were developed for calculating the emission of electrons from high-Z foils irradiated with x rays. XITRAN follows all individual elastic collisions of electrons with atoms, whereas XMTRAN uses the condensed-random-walk model. Both codes take into account photo-electrons, fluorescence radiation, and Auger electrons. Comparisons are made with an experiment by Dolan at Sandia Laboratories involving the backward and forward emission of electrons from a tantalum foil irradiated by 100-kV and 50-kV x-ray beams. There is good agreement between results from the XITRAN and XMTRAN codes. There emitted per incident x-ray photon, and in regard to the angular distribution of the emerging electrons. In regard to the electron energy spectra, there is fair agreement down to a spectral energy of 20 keV, whereas below 20 keV the calculated spectra lie considerably below the measurements

Bedrijfsuitkomsten in de Nederlandse particuliere bosbouw over 2004

Annual overview of yields, costs and farm results of private forestry holdings with more than 5 hectares of forest, based on an accountancy network consisting of about 150 holdings. This edition contains the results for 2004 and previous years, specified by area of forest and region. In addition, the yield prices for wood and the size of wood sales are shown. Finally, this report further specifies costs and yields by the functions private forestry companies serve, such as wood production, nature conservation, recreation and landscape, and game management.Resource /Energy Economics and Policy,

The Singularity Threshold of the Nonlinear Sigma Model Using 3D Adaptive Mesh Refinement

Numerical solutions to the nonlinear sigma model (NLSM), a wave map from 3+1 Minkowski space to S^3, are computed in three spatial dimensions (3D) using adaptive mesh refinement (AMR). For initial data with compact support the model is known to have two regimes, one in which regular initial data forms a singularity and another in which the energy is dispersed to infinity. The transition between these regimes has been shown in spherical symmetry to demonstrate threshold behavior similar to that between black hole formation and dispersal in gravitating theories. Here, I generalize the result by removing the assumption of spherical symmetry. The evolutions suggest that the spherically symmetric critical solution remains an intermediate attractor separating the two end states.Comment: 5 pages, 5 figures, 1 table; To be published in Phys. Rev. D.; Added discussion of initial data; Added figure and reference

Skin cancer risk and shade: comparing the risk of foresters with other outdoor workers

Background: Keratinocyte carcinoma (KC) is an increasingly important public health problem with an especially high prevalence in outdoor workers. In contrast to other occupations, foresters spend most of their outdoor time under the shade of trees. Objectives: We aimed to compare the unique sun exposure patterns and sun protection behaviour of foresters with those of other outdoor workers and their relation to the KC risk. Methods: In July 2018, a cross‐sectional study was conducted at an international forestry fair using a questionnaire about health awareness and skin cancer screening by dermatologists to assess the prevalence of KC. Results: A total of 591 participants (78.7% male; mean age 46.8 ± 16.2 years) including 193 foresters were enrolled. Of all foresters, 72% experienced sunburns (solar erythema) within the past year and 50% of them experienced the worst sunburn during work. Foresters were most likely to often/always wear protective clothes (29.0%) but were least likely to often/always avoid midday sun (23.8%) and stay in the shade (31.1%). Having an outdoor profession or spending hours outside for leisure was negatively associated with sun protection. Skin examination revealed an overall KC prevalence of 16.7%, with 16.5% of foresters being affected. Conclusion: Despite being protected by trees, the risk of KC for foresters is comparable to that of other professional groups. Shade alone may not provide sufficient protection. Additional sun protection measures are necessary

Prior-based Bayesian information criterion

We present a new approach to model selection and Bayes factor determination, based on Laplace expansions (as in BIC), which we call Prior-based Bayes Information Criterion (PBIC). In this approach, the Laplace expansion is only done with the likelihood function, and then a suitable prior distribution is chosen to allow exact computation of the (approximate) marginal likelihood arising from the Laplace approximation and the prior. The result is a closed-form expression similar to BIC, but now involves a term arising from the prior distribution (which BIC ignores) and also incorporates the idea that different parameters can have different effective sample sizes (whereas BIC only allows one overall sample size n). We also consider a modification of PBIC which is more favourable to complex models

Bedrijfsuitkomsten in de Nederlandse particuliere bosbouw over 2003

Jaarlijks overzicht van opbrengsten, kosten en bedrijfsresultaten van particuliere bosbedrijven met meer dan 5 ha bos op basis van een Informatienet bestaande uit circa 150 bedrijven. Deze editie bevat uitkomsten over 2001 en voorgaande jaren, gespecificeerd naar oppervlakte bos en regio. Verder worden de opbrengstprijzen van hout evenals de omvang van de houtverkopen weergegeven. Tot slot wordt in deze rapportage verslag gedaan van een verbijzondering van kosten en opbrengsten naar de functies die particuliere bosbedrijven vervullen (houtproductie, natuurbehoud, recreatie en landschap en wildbeheer). Gemiddeld leed het Nederlandse particuliere bosbedrijf met meer dan 5 ha bos in 2001 een verlies van 56 euro per ha bos, wat gelijk is aan 2000, maar slechter dan in 1999. Het resultaat wordt sterk bepaald door de omvang van de bedrijfsoppervlakte. Bij de grotere bedrijven, met meer dan 50 ha bos, bedroeg het verlies 17 euro per ha