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The theory of special relativity finds a convenient formulation in Minkowski spacetime, a mathematical structure that combines three dimensions of space with a single dimension of time. In this formalism, distances in space can be measured by how long light takes to travel that distance, e.g., a light-year is a measure of distance, and a meter is now defined in terms of how far light travels in a certain amount of time. Two events in Minkowski spacetime are separated by an invariant interval, which can be either space-like, light-like, or time-like. Events that have a time-like separation cannot be simultaneous in any frame of reference, there must be a temporal component (and possibly a spatial one) to their separation. Events that have a space-like separation will be simultaneous in some frame of reference, and there is no frame of reference in which they do not have a spatial separation. Different observers may calculate different distances and different time intervals between two events, but the invariant interval between the events is independent of the observer (and his velocity).
What are two events in Minkowski spacetime separated by?
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The answer: by an invariant interval


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Some organisms have multiple copies of chromosomes: diploid, triploid, tetraploid and so on. In classical genetics, in a sexually reproducing organism (typically eukarya) the gamete has half the number of chromosomes of the somatic cell and the genome is a full set of chromosomes in a diploid cell. The halving of the genetic material in gametes is accomplished by the segregation of homologous chromosomes during meiosis. In haploid organisms, including cells of bacteria, archaea, and in organelles including mitochondria and chloroplasts, or viruses, that similarly contain genes, the single or set of circular or linear chains of DNA (or RNA for some viruses), likewise constitute the genome. The term genome can be applied specifically to mean what is stored on a complete set of nuclear DNA (i.e., the "nuclear genome") but can also be applied to what is stored within organelles that contain their own DNA, as with the "mitochondrial genome" or the "chloroplast genome". Additionally, the genome can comprise non-chromosomal genetic elements such as viruses, plasmids, and transposable elements.
What are two cellular organelles which contain genetic material?
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The answer: mitochondria and chloroplasts


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This office was first held by Gabriel Nicolas de la Reynie, who had 44 commissaires de police (police commissioners) under his authority. In 1709, these commissioners were assisted by inspecteurs de police (police inspectors). The city of Paris was divided into 16 districts policed by the commissaires, each assigned to a particular district and assisted by a growing bureaucracy. The scheme of the Paris police force was extended to the rest of France by a royal edict of October 1699, resulting in the creation of lieutenants general of police in all large French cities and towns.
When was Paris's police system expanded to the rest of France?
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The answer: October 1699


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On March 30, 2015, it was announced that West is a co-owner, with various other music artists, in the music streaming service Tidal. The service specialises in lossless audio and high definition music videos. Jay Z acquired the parent company of Tidal, Aspiro, in the first quarter of 2015. Including Beyoncé and Jay-Z, sixteen artist stakeholders (such as Rihanna, Beyoncé, Madonna, Chris Martin, Nicki Minaj and more) co-own Tidal, with the majority owning a 3% equity stake. The idea of having an all artist owned streaming service was created by those involved to adapt to the increased demand for streaming within the current music industry, and to rival other streaming services such as Spotify, which have been criticised for their low payout of royalties. "The challenge is to get everyone to respect music again, to recognize its value", stated Jay-Z on the release of Tidal.
What platform was Kanye named  a co-owner of in 2015?
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The answer:
Tidal