In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

An approximation of it named for Russell uses the TDS value to determine one of its parameters via the Langelier approximation, while one constant that appears in it has units of moles per kilogram to the one half power, according the Bates-Guggenheim convention. Along with Guggenheim, Scatchard and Bronsted improved upon this model by developing the SIT theory, and that model has a better fit than a modification of it named for Davies. This relationship assumes the existence of only long-range interactions, and it was extended to account for Brownian motion by Lars Onsager. It assumes that the solvent is structure-less and that the solution is dilute, and the theory behind it implies that the electrostatic potential falls off exponentially when r is greater than the atomic radius due to screening by counter ions. For 10 points, identify this equation which is used to calculate the activity coefficients, and is named for a German and a Dutch scientist.
Science

Imetelstat, a potential new cancer therapy agent, works by targeting the enzyme that repairs these structures. Blackburn, Greider, and Szostak received the 2009 Nobel Prize for determining the role of these structures, which typically adopt a G-quadruplex shape. The shortening of these structures explains the Hayflick limit to cell division and is the basis for the cellular theory of aging, and that shortening of these structures can lead to cell senescence or apoptosis. Consisting of thousands of TTAGGG repeats in humans, name these end sequences of chromosomes that prevent genes from being lost during DNA replication.
Science

Egorov's theorem relates two types of this property for measurable functions. A theorem named for Vitali applies when a dominating function cannot be found; when one can, Lebesgue's dominated this theorem applies. This property also makes Fatou's lemma reduce to that theorem. The pointwise type of this property is weaker than the uniform type. On the complex plane, this condition's equivalent is named for Cauchy, since there, it's possible for each element past some point to be arbitrarily close, without approaching a unique value. For 10 points, name this property lacked by the partial sums of the harmonic series, which requires that a sequence has a limit.
Science