Multi-GPU Acceleration of the iPIC3D Implicit Particle-in-Cell Code

iPIC3D is a widely used massively parallel Particle-in-Cell code for the simulation of space plasmas. However, its current implementation does not support execution on multiple GPUs. In this paper, we describe the porting of iPIC3D particle mover to GPUs and the optimization steps to increase the performance and parallel scaling on multiple GPUs. We analyze the strong scaling of the mover on two GPU clusters and evaluate its performance and acceleration. The optimized GPU version which uses pinned memory and asynchronous data prefetching outperform their corresponding CPU versions by 5-10x on two different systems equipped with NVIDIA K80 and V100 GPUs.Comment: Accepted for publication in ICCS 201

Monitoring water-chemistry evolution in the bentonite buffer using magnets: Effects of corrosion on buffer stability

Bentonite has been chosen as a buffer material by several national nuclear-waste management companies because of its swelling capacity and low water permeability, and because it retards the transport of radionuclides and corrosion products toward the geosphere. The aim of the present study was to develop a magnetic material that has the ability to detect changes in groundwater compositions in an underground nucleardeposit facility through variation in its magnetic properties with time. The present study has investigated the effect of the corrosion of NdFeB magnets on the Na-bentonite buffer under different environmental conditions. Seven different aqueous solutions were used for long-time exposure tests (708C, 5 months) with fragments of NdFeB magnets and powdered Na-bentonite. The corrosion of NdFeB alloy had no detectable effect on the mineralogy of the clay minerals, and any change on the bentonite matrix, measured through X-ray diffraction analysis, was related to the different initial chemistry of the solutions.© 2016 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/)

Monetary Policies And Credit Financing As Factors In Agricultural Productivity In Cross River State

The study evaluates the influence of credit policies on institutional lending behaviour of farmers in Cross River State. It also ascertains the relationship between credit and agricultural development. Using econometric methods, results reveal that credit quota and portfolio lending devices and pursuit of cheap interest rate polices has negative effect on credit supply while policies associated with plough back of rural savings mobilization and availability of guarantee were marginally effective. Results also show that farmers demand for credit was influenced mainly by the availability of credit subsidies and availability of guarantees. Also, the study showed that a positive but inelastic relationship exist between credit and agricultural output. Finally, it was revealed that some factors which militate against the effectiveness of agricultural credit polices include lack of viable technologies, defective production environments and wrong perception of the roles of credit in development. An agenda for credit policy reforms stressed the need to evolve and adopt policies, which foster desirable financial technologies, which serve both the interest of institutional borrowers and lenders. Keywords: Agricultural Productivity, Credit policies, Agricultural development, Monetary policies and Cross River State Global Journal of Agricultural Sciences Vol. 7 (1) 2008: pp. 1-

Matrix Metalloproteinase 13 Is Induced in Fibroblasts in Polyomavirus Middle T Antigen-Driven Mammary Carcinoma without Influencing Tumor Progression

Matrix metalloproteinase (MMP) 13 (collagenase 3) is an extracellular matrix remodeling enzyme that is induced in myofibroblasts during the earliest invasive stages of human breast carcinoma, suggesting that it is involved in tumor progression. During progression of mammary carcinomas in the polyoma virus middle T oncogene mouse model (MMTV-PyMT), Mmp13 mRNA was strongly upregulated concurrently with the transition to invasive and metastatic carcinomas. As in human tumors, Mmp13 mRNA was found in myofibroblasts of invasive grade II and III carcinomas, but not in benign grade I and II mammary intraepithelial neoplasias. To determine if MMP13 plays a role in tumor progression, we crossed MMTV-PyMT mice with Mmp13 deficient mice. The absence of MMP13 did not influence tumor growth, vascularization, progression to more advanced tumor stages, or metastasis to the lungs, and the absence of MMP13 was not compensated for by expression of other MMPs or tissue inhibitor of metalloproteinases. However, an increased fraction of thin collagen fibrils was identified in MMTV-PyMT;Mmp13−/− compared to MMTV-PyMT;Mmp13+/+ tumors, showing that collagen metabolism was altered in the absence of MMP13. We conclude that the expression pattern of Mmp13 mRNA in myofibroblasts of invasive carcinomas in the MMTV-PyMT breast cancer model recapitulates the expression pattern observed in human breast cancer. Our results suggest that MMP13 is a marker of carcinoma-associated myofibroblasts of invasive carcinoma, even though it does not make a major contribution to tumor progression in the MMTV-PyMT breast cancer model