18 research outputs found

    Antibiotic-Induced Anomalous Statistics of Collective Bacterial Swarming

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    Under sublethal antibiotics concentrations, the statistics of collectively swarming Bacillus subtilis transitions from normal to anomalous, with a heavy-tailed speed distribution and a two-step temporal correlation of velocities. The transition is due to changes in the properties of the bacterial motion and the formation of a motility-defective subpopulation that self-segregates into regions. As a result, both the colonial expansion and the growth rate are not affected by antibiotics. This phenomenon suggests a new strategy bacteria employ to fight antibiotic stress

    Competitive analysis of flash-memory algorithms

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    Abstract. The cells of flash memories can only endure a limited number of write cycles, usually between 10,000 and 1,000,000. Furthermore, cells containing data must be erased before they can store new data, and erasure operations erase large blocks of memory, not individual cells. To maximize the endurance of the device (the amount of useful data that can be written to it before one of its cells wears out), flash-based systems move data around in an attempt to reduce the total number of erasures and to level the wear of the different erase blocks. This data movement introduces interesting online problems called wear-leveling problems. We show that a simple randomized algorithm for one problem is essentially optimal. For a more difficult problem, we show that clever offline algorithms can improve upon naive approaches, but online algorithms essentially cannot.

    Competitive analysis of flash memory algorithms

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    Effect of wine on carotid atherosclerosis in type 2 diabetes: A 2-year randomized controlled trial

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    BACKGROUND/OBJECTIVES: The progression of carotid-plaque volume in patients with type 2 diabetes is common. Previous observational studies showed an association between moderate alcohol and reduced risk of coronary disease. We examined whether consuming moderate wine affects the progression of carotid atherosclerosis. SUBJECTS/METHODS: In the CASCADE (CArdiovaSCulAr Diabetes and Ethanol), a 2-year randomized controlled trial, we randomized abstainers with type 2 diabetes were to drink 150 ml of either red wine, white wine, or water, provided for 2 years. In addition, groups were guided to maintain a Mediterranean diet. We followed 2-year changes in carotid total plaque volume (carotid-TPV) and carotid vessel wall volume (carotid-VWV), using three-dimensional ultrasound. RESULTS: Carotid images were available from 174 of the 224 CASCADE participants (67% men; age = 59 yr; HbA1C = 6.8%). Forty-five percent had detectable plaque at baseline. After 2 years, no significant progression in carotid-TPV was observed (water, -1.4 (17.0) mm CONCLUSIONS: No progression in carotid-TPV was observed. In subgroup analyses, those with the greatest plaque burden assigned to drink wine may have had a small regression of plaque burden
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