60 research outputs found

    Isomorphic routing on a toroidal mesh

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    We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every processor is actively routing messages with the same descriptors as any other processor. We call this isomorphic routing. Our objective is to find the isomorphic routing schedule with least makespan. We consider a number of variations on the problem, yielding complexity results from O(k) to NP-complete. Most of our results follow after we transform the problem into a scheduling problem, where it is related to other well-known scheduling problems

    Neuroendocrine Control of Hepatic Gluconeogenesis

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    Glucose is intricately regulated in human body through a complex network of hormonal and neuronal factors. A series of evidence suggests that the gastrointestinal tract and the central nervous system play prominent roles in the regulation of glucose and energy homeostasis. The gut senses the nutrient supply to co-ordinate the release of hormones that activate neuronal networks in the brain, leading to the subsequent modulation of hepatic glucose output via the gut-brain-liver axis. The gut hormones also act on multiple peripheral tissues to regulate glucose level through an insulin-dependent and/or -independent mechanism. The brain, especially the hypothalamus, could also response to the hormones such as insulin and leptin and different nutrients to modulate the glucose homeostasis. In this chapter, we review the gut-brain-liver axis and the role of this organ interaction in the control of glucose homeostasis. A better understanding of these pathways will provide novel strategies for improved glycaemic control

    Hormonal Regulation of Cholesterol Homeostasis

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    Cholesterol homeostasis is tightly regulated by a group of endocrine hormones under physiological conditions. Hormonal dysregulation is often associated with disturbed cholesterol homeostasis, resulting in many clinical disorders including atherosclerosis, fatty liver and metabolic syndrome. Circulating hormones regulate cholesterol metabolism by altering levels of relative genes either through their interactions with nuclear receptors or by interfering with bile acid signaling pathways. A better understanding of hormonal regulation of cholesterol metabolism would improve our likelihood of identifying effective and selective targets for the intervention of disturbed cholesterol. In this review, we discuss selected hormones critical for the cholesterol balance, including thyroid hormone, sex hormones, growth hormone, glucagon and irisin. We focus our discussion on the most recent advance in clinical epidemiology, animal mechanistic studies and the clinical application

    Arbitrating Traffic Contention for Power Saving with Multiple PSM Clients

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    Data transmission over WiFi quickly drains the batteries of mobile devices. Although the IEEE 802.11 standards provide power save mode (PSM) to help mobile devices conserve energy, PSM fails to bring expected benefits in many real scenarios. In particular, when multiple PSM mobile devices associate to a single access point (AP), PSM does not work well under transmission contention. Optimizing power saving of multiple PSM clients is a challenging task, because each PSM client expects to complete data transmission early so that it can turn to low power mode. In this paper, we define an energy conserving model to describe the general PSM traffic contention problem. We prove that the optimization of energy saving for multiple PSM clients under constraint is an NPcomplete problem. Following this direction, we propose a solution called harmonious power saving mechanism (HPSM) to address one specific case, in which multiple PSM clients associate to a single AP. In HPSM, we first use a basic sociological concept to define the richness of a PSM client based on the link resource it consumes. Then, we separate these poor PSM clients from rich PSM clients in terms of link resource consumption and favor the former to save power when they face PSM transmission contention. We implement prototypes of HPSM based on the open source projects Mad-wifi and NS-2. Our evaluations show that HPSM can help the poor PSM clients effectively save power while only slightly degrading the rich PSM clients\u27 performance in comparison with the existing PSM solutions

    Mutations in KEOPS-Complex Genes Cause Nephrotic Syndrome with Primary Microcephaly

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    Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced apoptosis. Knockdown of OSGEP or TP53RK induced defects in the actin cytoskeleton and decreased the migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identified four new monogenic causes of GAMOS, describe a link between KEOPS function and human disease, and delineate potential pathogenic mechanisms

    Multi-Operation Multi-Machine Scheduling

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    Abstract. In the multi-operation scheduling that arises in industrial engineering, each job contains multiple tasks (operations) that require execution in different shops. It is assumed that in each shop there is only one machine to perform the required operations. In this paper, a parallel model of multi-operation scheduling is proposed, in which multiple machines are available in each shop to perform the same type of operations. A multi-machine open-shop scheduling problem is studied in detail
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