Finding Top-k Dominance on Incomplete Big Data Using Map-Reduce Framework

Incomplete data is one major kind of multi-dimensional dataset that has random-distributed missing nodes in its dimensions. It is very difficult to retrieve information from this type of dataset when it becomes huge. Finding top-k dominant values in this type of dataset is a challenging procedure. Some algorithms are present to enhance this process but are mostly efficient only when dealing with a small-size incomplete data. One of the algorithms that make the application of TKD query possible is the Bitmap Index Guided (BIG) algorithm. This algorithm strongly improves the performance for incomplete data, but it is not originally capable of finding top-k dominant values in incomplete big data, nor is it designed to do so. Several other algorithms have been proposed to find the TKD query, such as Skyband Based and Upper Bound Based algorithms, but their performance is also questionable. Algorithms developed previously were among the first attempts to apply TKD query on incomplete data; however, all these had weak performances or were not compatible with the incomplete data. This thesis proposes MapReduced Enhanced Bitmap Index Guided Algorithm (MRBIG) for dealing with the aforementioned issues. MRBIG uses the MapReduce framework to enhance the performance of applying top-k dominance queries on huge incomplete datasets. The proposed approach uses the MapReduce parallel computing approach using multiple computing nodes. The framework separates the tasks between several computing nodes that independently and simultaneously work to find the result. This method has achieved up to two times faster processing time in finding the TKD query result in comparison to previously presented algorithms

History of Neuroscience: Mesoglia and Microglia

Microglia are mononuclear phagocytes that reside within the central nervous system (CNS). They differ from macroglia (astrocytes and oligodendrocytes) in terms of their origin, phenotype and functions, but more closely resemble tissue-resident macrophages in all these aspects. The principal role of microglia is to provide a first line of defence against pathological insults at this primary site. Modern consensus holds that microglia are of myeloid origin, much like tissue-resident mononuclear phagocytes within other organs, and arise during fetal development from progenitors in the yolk sac, liver or spleen or from mesenchymal tissues surrounding the nervous system that subsequently seed the CNS during gestation and perinatally, and differentiate morphologically to ramified and immunophenotypically suppressed adult varieties (20, 31). These intriguing and controversial cells have been the focus of intense scientific research for the past two decades, and the subject of many recent reviews to which the reader is referred (8, 11, 12, 14-16, 18, 20-22, 24-27, 31-34, 54-57)