A High-Throughput Solver for Marginalized Graph Kernels on GPU

We present the design and optimization of a linear solver on General Purpose GPUs for the efficient and high-throughput evaluation of the marginalized graph kernel between pairs of labeled graphs. The solver implements a preconditioned conjugate gradient (PCG) method to compute the solution to a generalized Laplacian equation associated with the tensor product of two graphs. To cope with the gap between the instruction throughput and the memory bandwidth of current generation GPUs, our solver forms the tensor product linear system on-the-fly without storing it in memory when performing matrix-vector dot product operations in PCG. Such on-the-fly computation is accomplished by using threads in a warp to cooperatively stream the adjacency and edge label matrices of individual graphs by small square matrix blocks called tiles, which are then staged in registers and the shared memory for later reuse. Warps across a thread block can further share tiles via the shared memory to increase data reuse. We exploit the sparsity of the graphs hierarchically by storing only non-empty tiles using a coordinate format and nonzero elements within each tile using bitmaps. Besides, we propose a new partition-based reordering algorithm for aggregating nonzero elements of the graphs into fewer but denser tiles to improve the efficiency of the sparse format.We carry out extensive theoretical analyses on the graph tensor product primitives for tiles of various density and evaluate their performance on synthetic and real-world datasets. Our solver delivers three to four orders of magnitude speedup over existing CPU-based solvers such as GraKeL and GraphKernels. The capability of the solver enables kernel-based learning tasks at unprecedented scales

Low-energy excitations in the magnetized state of the bond-alternating quantum S=1 chain system NTENP

High intensity inelastic neutron scattering experiments on the S=1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C9D24N4)(NO2)ClO4 (NTENP) are performed in magnetic fields of up to 14.8~T. Excitation in the high field magnetized quantum spin solid (ordered) phase are investigated. In addition to the previously observed coherent long-lived gap excitation [M. Hagiwara et al., Phys. Rev. Lett 94, 177202 (2005)], a broad continuum is detected at lower energies. This observation is consistent with recent numerical studies, and helps explain the suppression of the lowest-energy gap mode in the magnetized state of NTENP. Yet another new feature of the excitation spectrum is found at slightly higher energies, and appears to be some kind of multi-magnon state.Comment: 5 pages, 4 fugure

Behavior of Some Earth Dams on Liquefiable Soil

The 1977 March 4 Vrancea earthquake emphasized several zones with liquefiable materials on Romanian territory. Some earth dams of such zones, placed to over 200 km from the earthquake epicenter were damaged. Important hydropower works are at present in different design or construction stages in such area, comprising long earth dams. The Seismic analysis procedure applied to their design was based on the finite element method. Some characteristic cross - sections of the earth dams in different versions have been studied. The analysed sections had different shapes (with and without stabilizing benches downstream) and included different zoning of the materials (sand fine sand and free draining materials). The analyses pointed out the importance of the drainage blanket at the base of the dam for the increase of the liquefaction strength capacity of the soil - structure system. Some improvement works in certain zones of the foundation soil resulted as being necessary

Comments Upon an Earth Dam Severely Damaged by Foundation Liquefaction

The damage of the Draganesti earth dam on lower sector of the Olt river due to foundation liquefaction during 30th May 1990, 0.12 g in site maximum acceleration, Vrancea earthquake is described. The dam is up to 20 m maximum height and border cross-wise and laterally the reservoir with 12.6 km length of the low head hydroelectric power station. The damage consisting of a large slide with about 60 m length at the dam downstream face and some cracks and lift-up of the reinforced concrete slabs at the corresponding upstream toe zone was placed in a zone where any special technology for increasing the relative density of the foundation loose sand layer was not applied. The natural relative density of the above mentioned layer having 1.20…7.00 m thickness was Dr =0.15…0.30, but it was increased up to 0.55…0.65 by vibrated-compacted gravel microcolumns technology, that was applied for over 80 % of dam foundation area. A comprehensive seismic backanalysis is performed in order to explain the damage mechanism

Infection with a Virulent Strain of Wolbachia Disrupts Genome Wide-Patterns of Cytosine Methylation in the Mosquito Aedes aegypti

BACKGROUND Cytosine methylation is one of several reversible epigenetic modifications of DNA that allow a greater flexibility in the relationship between genotype and phenotype. Methylation in the simplest models dampens gene expression by modifying regions of DNA critical for transcription factor binding. The capacity to methylate DNA is variable in the insects due to diverse histories of gene loss and duplication of DNA methylases. Mosquitoes like Drosophila melanogaster possess only a single methylase, DNMT2. DESCRIPTION Here we characterise the methylome of the mosquito Aedes aegypti and examine its relationship to transcription and test the effects of infection with a virulent strain of the endosymbiont Wolbachia on the stability of methylation patterns. CONCLUSION We see that methylation in the A. aegypti genome is associated with reduced transcription and is most common in the promoters of genes relating to regulation of transcription and metabolism. Similar gene classes are also methylated in aphids and honeybees, suggesting either conservation or convergence of methylation patterns. In addition to this evidence of evolutionary stability, we also show that infection with the virulent wMelPop Wolbachia strain induces additional methylation and demethylation events in the genome. While most of these changes seem random with respect to gene function and have no detected effect on transcription, there does appear to be enrichment of genes associated with membrane function. Given that Wolbachia lives within a membrane-bound vacuole of host origin and retains a large number of genes for transporting host amino acids, inorganic ions and ATP despite a severely reduced genome, these changes might represent an evolved strategy for manipulating the host environments for its own gain. Testing for a direct link between these methylation changes and expression, however, will require study across a broader range of developmental stages and tissues with methods that detect splice variants.This research was supported by The National Health and Medical Research Council of Australia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Evaluation of Florida Physicians’ Knowledge and Attitudes Toward Accessing the State Prescription Drug Monitoring Program as a Prescribing Tool

Objective The purpose of this study is to assess Florida physicians\u27 attitudes and knowledge toward accessing the state\u27s prescription drug monitoring program (PDMP). Design Five thousand medical doctors and osteopathic physicians licensed in Florida were randomly selected for a voluntary and anonymous 15-question self-administered survey approved by the Institutional Review Board. Surveys were distributed through U.S. postal service mail. Likert-scale questions were used to assess prior knowledge (1 = none to 5 = excellent) and attitudes toward accessing the PDMP (1 = strongly disagree to 5 = strongly agree). Results The study yielded a response rate of 7.8%, 71.5% of whom agreed or strongly agreed that the PDMP is a useful tool. Among participants that have access and answered the PDMP usefulness question, 94.8% agree or strongly agree that it is a useful tool. There were 63 out of 64 physicians (98.4%) who conducted 25 or more searches who agreed or strongly agreed that the PDMP is a useful tool for monitoring patients\u27 controlled substance histories. There were 72.5% of participants with access that answered the “doctor shopping” question who agreed that “doctor shopping” will decrease. Among the 64 most frequent PDMP users, 69.4% agreed or strongly agreed that they have prescribed fewer controlled substances after accessing the PDMP. Conclusions The study revealed that a majority of participants believe that the PDMP is a useful tool for monitoring patients\u27 controlled substance histories. More continuing education programs should be provided to Florida physicians to enhance their knowledge regarding PDMPs

Critical comments on the philosophical context of Ludwig von Mises’s ‘Human action’

Mises’s work of ‘Human action’ is analyzed in relation to the methodological conceptions of his predecessor C. Menger and of his successor F. von Hayek. Also, it is placed in the continuation of one of his previous works and in contrast to one that followed it. Some of his ideas can be better understood in such a way, while others show themselves as contradictory. It results that his attempt to combine apriorism with scientific realism explains some of major difficulties of Mises’s argumentation

Effects of False Tilt Cues on the Training of Manual Roll Control Skills

This paper describes a transfer-of-training study performed in the NASA Ames Vertica lMotion Simulator. The purpose of the study was to investigate the effect of false tilt cues on training and transfer of training of manual roll control skills. Of specific interest were the skills needed to control unstable roll dynamics of a mid-size transport aircraft close to the stall point. Nineteen general aviation pilots trained on a roll control task with one of three motion conditions: no motion, roll motion only, or reduced coordinated roll motion. All pilots transferred to full coordinated roll motion in the transfer session. A novel multimodal pilot model identification technique was successfully applied to characterize how pilots' use of visual and motion cues changed over the course of training and after transfer. Pilots who trained with uncoordinated roll motion had significantly higher performance during training and after transfer, even though they experienced the false tilt cues. Furthermore, pilot control behavior significantly changed during the two sessions, as indicated by increasing visual and motion gains, and decreasing lead time constants. Pilots training without motion showed higher learning rates after transfer to the full coordinated roll motion case