Capacity and Security of Heterogeneous Distributed Storage Systems

We study the capacity of heterogeneous distributed storage systems under repair dynamics. Examples of these systems include peer-to-peer storage clouds, wireless, and Internet caching systems. Nodes in a heterogeneous system can have different storage capacities and different repair bandwidths. We give lower and upper bounds on the system capacity. These bounds depend on either the average resources per node, or on a detailed knowledge of the node characteristics. Moreover, we study the case in which nodes may be compromised by an eavesdropper, and give bounds on the system secrecy capacity. One implication of our results is that symmetric repair maximizes the capacity of a homogeneous system, which justifies the model widely used in the literature.Comment: 7 pages, 2 figure

Towards High-Order CFD-DEM: Development and Validation

CFD-DEM is used to simulate solid-fluid systems. DEM models the motion of discrete particles while CFD models the fluid phase. Coupling both necessitates the calculation of the void fraction and the solid-fluid forces resulting in a computationally expensive method. Additionally, evaluating volume-averaged quantities locally restricts particle to cell size ratios limiting the accuracy of the CFD. To mitigate these limitations, we develop a monolithic finite element CFD-DEM solver which supports dynamically load-balanced parallelization. This allows for more stable, accurate and time efficient simulations as load balancing ensures the even distribution of workloads among processors; thus, exploiting available resources efficiently. Our solver also supports high order schemes; thus, allowing the use of larger elements enhancing the validity and stability of the void fraction schemes while achieving better accuracy. We verify and validate our CFD-DEM solver with a large array of test cases: the Rayleigh Taylor instability, particle sedimentation, a fluidized bed, and a spouted bed

Fidelity of flight control systems in a real-time optimal trajectory planner

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991.Includes bibliographical references (leaves 56).by Toni El-Dirani.M.S

Primary Hepatic Diffuse Large B-cell Lymphoma Mimicking Acute Fulminant Hepatitis

Primary hepatic lymphoma (PHL) is a rare variant of non-Hodgkin's lymphoma. Diffuse hepatic involvement is uncommon and therefore presentation as progressive hepatitis or acute fulminant hepatic failure is rare. Acute onset of signs and symptoms can mimic a variety of infectious and inflammatory disorders, thus delaying the diagnosis. A high index of suspicion and liver biopsy early in the course of liver dysfunction may establish the diagnosis and allow rapid initiation of chemotherapy to prevent a fatal outcome. In this report, we describe a rare case of fulminant primary hepatic diffuse large B-cell lymphoma in a 55-year-old woman who died 2 weeks after admission, before the initiation of chemotherapy

Trends in yeast diversity discovery

Yeasts, usually defined as unicellular fungi, occur in various fungal lineages. Hence, they are not a taxonomic unit, but rather represent a fungal lifestyle shared by several unrelated lineages. Although the discovery of new yeast species occurs at an increasing speed, at the current rate it will likely take hundreds of years, if ever, before they will all be documented. Many parts of the earth, including many threatened habitats, remain unsampled for yeasts and many others are only superficially studied. Cold habitats, such as glaciers, are home to a specific community of cold-adapted yeasts, and, hence, there is some urgency to study such environments at locations where they might disappear soon due to anthropogenic climate change. The same is true for yeast communities in various natural forests that are impacted by deforestation and forest conversion. Many countries of the so-called Global South have not been sampled for yeasts, despite their economic promise. However, extensive research activity in Asia, especially China, has yielded many taxonomic novelties. Comparative genomics studies have demonstrated the presence of yeast species with a hybrid origin, many of them isolated from clinical or industrial environments. DNA-metabarcoding studies have demonstrated the prevalence, and in some cases dominance, of yeast species in soils and marine waters worldwide, including some surprising distributions, such as the unexpected and likely common presence of Malassezia yeasts in marine habitats.TG acknowledges support from the Spanish Ministry of Science and Innovation for grant PGC2018-099921-B-I00, cofounded by European Regional Development Fund (ERDF); from the Catalan Research Agency (AGAUR) SGR423; from the European Union’s Horizon 2020 research and innovation program (ERC-2016–724173); from the Gordon and Betty Moore Foundation (Grant # GBMF9742). JG acknowledges support from the Lendület Program (award no. 96049) of the Hungarian Academy of Sciences and the Eötvös Lóránd Research Network. Q-MW was supported by grants No. 31961133020 and No. 31770018 from the National Natural Science Foundation of China (NSFC). ASA and FEB were supported by grant 9343 from the Gordon and Betty Moore Foundation: https://doi.org/10.37807/GBMF9343."Article signat per 12 autors/es: Teun Boekhout, Anthony S. Amend, Fouad El Baidouri, Toni Gabaldón, József Geml, Moritz Mittelbach, Vincent Robert, Chen Shuhui Tan, Benedetta Turchetti, Duong Vu, Qi-Ming Wang & Andrey Yurkov "Postprint (published version