62 research outputs found

    Symbiotic Organisms Search Optimization to Predict Optimal Thread Count for Multi-threaded Applications

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    Multicore systems have emerged as a cost-effective option for the growing demands for high-performance, low-energy computing. Thread management has long been a source of concern for developers, as overheads associated with it reduce the overall throughput of the multicore processor systems. One of the most complex problems with multicore processors is determining the optimal number of threads for the execution of multithreaded programs. To address this issue, this paper proposes a novel solution based on a modified symbiotic organism search (MSOS) algorithm which is a bio-inspired algorithm used for optimization in various engineering domains. This technique uses mutualism, commensalism and parasitism behaviours seen in organisms for searching the optimal solutions in the available search space. The algorithm is simulated on the NVIDIA DGX Intel-Xeon E5-2698-v4 server with PARSEC 3.0 benchmark suit.  The results show that keeping the thread count equal to the number of processors available in the system is not necessarily the best strategy to get maximum speedup when running multithreaded programs. It was also observed that when programs are run with the optimal thread count, the execution time is substantially decreased, resulting in energy savings due to the use of fewer processors than are available in the system

    How Chromatin Is Remodelled during DNA Repair of UV-Induced DNA Damage in Saccharomyces cerevisiae

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    Global genome nucleotide excision repair removes DNA damage from transcriptionally silent regions of the genome. Relatively little is known about the molecular events that initiate and regulate this process in the context of chromatin. We've shown that, in response to UV radiation–induced DNA damage, increased histone H3 acetylation at lysine 9 and 14 correlates with changes in chromatin structure, and these alterations are associated with efficient global genome nucleotide excision repair in yeast. These changes depend on the presence of the Rad16 protein. Remarkably, constitutive hyperacetylation of histone H3 can suppress the requirement for Rad7 and Rad16, two components of a global genome repair complex, during repair. This reveals the connection between histone H3 acetylation and DNA repair. Here, we investigate how chromatin structure is modified following UV irradiation to facilitate DNA repair in yeast. Using a combination of chromatin immunoprecipitation to measure histone acetylation levels, histone acetylase occupancy in chromatin, MNase digestion, or restriction enzyme endonuclease accessibility assays to analyse chromatin structure, and finally nucleotide excision repair assays to examine DNA repair, we demonstrate that global genome nucleotide excision repair drives UV-induced chromatin remodelling by controlling histone H3 acetylation levels in chromatin. The concerted action of the ATPase and C3HC4 RING domains of Rad16 combine to regulate the occupancy of the histone acetyl transferase Gcn5 on chromatin in response to UV damage. We conclude that the global genome repair complex in yeast regulates UV-induced histone H3 acetylation by controlling the accessibility of the histone acetyl transferase Gcn5 in chromatin. The resultant changes in histone H3 acetylation promote chromatin remodelling necessary for efficient repair of DNA damage. Recent evidence suggests that GCN5 plays a role in NER in human cells. Our work provides important insight into how GG-NER operates in chromatin

    Using fMRI Brain Activation to Identify Cognitive States Associated with Perception of Tools and Dwellings

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    Previous studies have succeeded in identifying the cognitive state corresponding to the perception of a set of depicted categories, such as tools, by analyzing the accompanying pattern of brain activity, measured with fMRI. The current research focused on identifying the cognitive state associated with a 4s viewing of an individual line drawing (1 of 10 familiar objects, 5 tools and 5 dwellings, such as a hammer or a castle). Here we demonstrate the ability to reliably (1) identify which of the 10 drawings a participant was viewing, based on that participant's characteristic whole-brain neural activation patterns, excluding visual areas; (2) identify the category of the object with even higher accuracy, based on that participant's activation; and (3) identify, for the first time, both individual objects and the category of the object the participant was viewing, based only on other participants' activation patterns. The voxels important for category identification were located similarly across participants, and distributed throughout the cortex, focused in ventral temporal perceptual areas but also including more frontal association areas (and somewhat left-lateralized). These findings indicate the presence of stable, distributed, communal, and identifiable neural states corresponding to object concepts
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