PPDD: scheduling multi-site divisible loads in single-level tree networks

This paper investigates scheduling strategies for divisible jobs/loads originating from multiple sites in hierarchical networks with heterogeneous processors and communication channels. In contrast, most previous work in the divisible load scheduling theory (DLT) literature mainly addressed scheduling problems with loads originating from a single processor. This is one of the first works that address scheduling multiple loads from multiple sites in the DLT paradigm. In addition, scheduling multi-site jobs is common in Grids and other general distributed systems for resource sharing and coordination. An efficient static scheduling algorithm PPDD (Processor-set Partitioning and Data Distribution Algorithm) is proposed to near-optimally distribute multiple loads among all processors so that the overall processing time of all jobs is minimized. The PPDD algorithm is applied to two cases: when processors are equipped with front-ends and when they are not equipped with front-ends. The application of the algorithm to homogeneous systems is also studied. Further, several important properties exhibited by the PPDD algorithm are proven through lemmas. To implement the PPDD algorithm, we propose a communication strategy. In addition, we compare the performance of the PPDD algorithm with a Round-robin Scheduling Algorithm (RSA), which is most commonly used. Extensive case studies through numerical analysis have been conducted to verify the theoretical findings.     

Thermal Stress Impacts on Reproductive Development and Grain Yield in Grain Legumes

Temperature stress (cold, heat) during reproductive development is one of the serious constraints to the productivity of grain legumes as their cultivation is expanding to warmer environments and temperature variability is increasing due to climate change. Grain legumes exposed to temperature below 10-15°C or above 30°C show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to substantial reduction in grain yield. For managing these effects of temperature extremes, it is important to improve the resistance of grain legumes by using improved breeding and genetic engineering tools. In this review article, the impact of both high and low temperature stress on different phases of the reproductive stage, from meiosis to grain filling, and the sensitivity of different reproductive organs to temperature extremes are discussed. The review also covers the management options to improve resistance to temperature stress in grain legumes. Furthermore, innovative breeding, genetic and molecular strategies in grain legumes against temperature stress are also discussed.     

High Defibrillation Threshold: The Science,Signs and Solutions

Defibrillation threshold (DFT) testing has traditionally been an integral part of implantable cardioverter defibrillator (ICD) implantation. With the increasing number of patients receiving ICDs, physicians are encountering high DFT more often than before. Tackling the problem of high DFT, warrants an in-depth understanding of the science of defibrillation including the key electrophysiological concepts and the underlying molecular mechanisms. Numerous factors have been implicated in the causation of high DFT. Due consideration to the past medical history, pharmacotherapy, laboratory data and cardiac imaging, help in assessing the pre-procedural risk for occurrence of high DFT. Drugs, procedural changes, type and location of ICD lead system are some of the key players in predicting DFT during implantation. In the event of encountering an unacceptably high DFT, we recommend to follow a step-wise algorithm. Ruling out procedural complications like pneumothorax and tamponade is imperative before embarking on a search for potentially reversible clinical or metabolic derangements. Finally, if these attempts fail, the electrophysiologist must choose from a wide range of options for device adjustment and system modification. Although this review article is meant to be a treatise on the science, signs and solutions for high DFT, it is bound by limitations of space and scope of the article.