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Topic Review
Discrete Global Grid
A Discrete Global Grid (DGG) is a mosaic which covers the entire Earth's surface. Mathematically it is a space partitioning: it consists of a set of non-empty regions that form a partition of the Earth’s surface. In a usual grid-modeling strategy, to simplify position calculations, each region is represented by a point, abstracting the grid as a set of region-points. Each region or region-point in the grid is called a cell. When each cell of a grid is subject to a recursive partition, resulting in a "series of discrete global grids with progressively finer resolution", forming a hierarchical grid, it is named Hierarchical DGG (sometimes "DGG system"). Discrete Global Grids are used as the geometric basis for the building of geospatial data structures. Each cell is related with data objects or values, or (in the hierarchical case) may be associated with other cells. DGGs have been proposed for use in a wide range of geospatial applications, including vector and raster location representation, data fusion, and spatial databases. The most usual grids are for horizontal position representation, using a standard datum, like WGS84. In this context is commom also to use a specific DGG as foundation for geocoding standardization. In the context of a spatial index, a DGG can assign unique identifiers to each grid cell, using it for spatial indexing purposes, in geodatabases or for geocoding.
  • 626
  • 03 Nov 2022
Topic Review
List of Volcanic Features on Io
This is a list of named volcanic surface features on Jupiter's moon Io. These names have been approved for use by the International Astronomical Union. The features listed below represent a subset of the total known volcanic features on Io's surface with the majority currently not having an officially approved name. The names of volcanic features on Io use a combination of a name derived from mythological figures from around the world related to the Sun, fire, volcanoes, thunder, or smithing, places from the Greek mythological story of Io, Dante's Inferno, or from the name of a nearby feature on Io's surface and an approved descriptive term. The descriptive term used is based on the type of feature named and how it was first discovered. Volcanoes that were first observed as an active feature from observations of a volcanic plume fit under the category of "Eruptive Center" and do not use a descriptive term, though portions of these features may have also received names that do use a descriptive term, like Prometheus Patera or Masubi Fluctus. Lava flows use the descriptive term fluctus or the plural fluctūs, e.g. Acala Fluctus. Volcanic depressions use the term patera or the plural paterae, e.g. Ah Peku Patera. The term has also become the generic term for referring to these structures. Small shield volcanoes use the term tholus or the plural tholi, e.g. Inachus Tholus. Finally, channels carved by volcanic lava flows through thermal erosion use the term vallis or the plural valles. See also the list of mountains on Io and the list of regions on Io.
  • 625
  • 02 Nov 2022
Topic Review
Nanotechnology Education
Nanotechnology education involves a multidisciplinary natural science education with courses such as physics, chemistry, mathematics and molecular biology. It is being offered by many universities around the world. The first program involving nanotechnology was offered by the University of Toronto's Engineering Science program, where nanotechnology could be taken as an option. Here is a partial list of universities offering nanotechnology education, and the degrees offered (Bachelor of Science, Master of Science, and/or Ph.D in Nanotechnology).
  • 623
  • 14 Oct 2022
Topic Review
Recombination Mediators Proteins
The recombination mediator proteins (RMPs) are ubiquitous and play a crucial role in genome stability. RMPs facilitate the loading of recombinases like RecA onto single-stranded (ss) DNA coated by single-strand binding proteins like SSB.
  • 622
  • 22 Apr 2021
Topic Review
Holeum
Holeums are hypothetical stable, quantized gravitational bound states of primordial or micro black holes. Holeums were proposed by L. K. Chavda and Abhijit Chavda in 2002. They have all the properties associated with cold dark matter. Holeums are not black holes, even though they are made up of black holes.
  • 621
  • 28 Sep 2022
Biography
Hans Kopfermann
Hans Kopfermann (26 April 1895, in Breckenheim near Wiesbaden – 28 January 1963, in Heidelberg) was a Germany atomic and nuclear physicist. He devoted his entire career to spectroscopic investigations, and he did pioneering work in measuring nuclear spin. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club. Kopfermann began his studies at the
  • 620
  • 29 Nov 2022
Topic Review
Yajnavalkya's 95 Years Cycle of Synchronisation
Yajnavalkya's 95 Years Cycle of Synchronisation is the model proposed by the great Indian philosopher Yajnavalkya which explains the mathematical concept of the synchronisation of the motions of the Sun and the Moon. Yajnavalkya invented the 95 years of the periodic cycle, when the solar and lunar motions get synchronised. This 95 years of the periodic cycle is also known as Yajnavalkya Cycle. 
  • 618
  • 25 Dec 2023
Topic Review
Shock Capturing Method
In computational fluid dynamics, shock-capturing methods are a class of techniques for computing inviscid flows with shock waves. The computation of flow containing shock waves is an extremely difficult task because such flows result in sharp, discontinuous changes in flow variables such as pressure, temperature, density, and velocity across the shock.
  • 616
  • 25 Nov 2022
Topic Review
Photoacoustic Imaging Techniques
2D materials can be used as carriers for delivering therapeutic agents into a lesion, leading to phototherapy. Various optical imaging techniques have been used for the monitoring of the treatment process. 
  • 616
  • 21 Feb 2021
Biography
George Doundoulakis
George James Doundoulakis (October 19, 1921 – March 17, 2007) was a Greek American physicist and soldier who worked under British Intelligence during World War II with SOE agent Patrick Leigh Fermor, and then served with the OSS in Thessaly, Greece. He is known by his twenty-six US Patents in the fields of radar, electronics, and narrowband television. Doundoulakis is best remembered for the
  • 614
  • 11 Nov 2022
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