Search results for "Shut down"
showing 3 items of 3 documents
A Calvin Bestiary
2017
This paper compares a number of mathematical models for the Calvin cycle of photosynthesis and presents theorems on the existence and stability of steady states of these models. Results on five-variable models in the literature are surveyed. Next a number of larger models related to one introduced by Pettersson and Ryde-Pettersson are discussed. The mathematical nature of this model is clarified, showing that it is naturally defined as a system of differential-algebraic equations. It is proved that there are choices of parameters for which this model admits more than one positive steady state. This is done by analysing the limit where the storage of sugars from the cycle as starch is shut d…
A Simple Complex on the Verge of Breakdown: Isolation of the Elusive Cyanoformate Ion
2014
Cyanide Hitches a Ride Cyanide is a by-product of the biosynthesis of ethylene in plants and it has been somewhat puzzling how the ion is safely removed before it can shut down enzymatic pathways by coordination to catalytic iron centers. A proposed mechanism has implicated the cyanoformate ion—essentially, a weak adduct of cyanide and carbon dioxide—as the initial product, although its lifetime was uncertain. Murphy et al. (p. 75 ; see the Perspective by Alabugin and Mohamed ) crystallized this previously elusive adduct and found that its solution-phase stability varies inversely with the dielectric properties of the medium. The results bolster a picture in which the adduct shuttles the cy…
A Late Roman industrial complex with glass furnaces in the northern area of Valencia
2008
Abstract Information from excavations in Conde de Trenor street (1997) and Cisneros square (1986 and 1998) has confirmed that this area situated in the north of Valencia was a river port district dedicated to commercial activities and storing goods during the Roman Imperial period and maybe also in the Republican period. At the end of the third century A.D. the function of these port buildings changed and the evidence suggests that they became industrial workshops. The bases of three circular furnaces were found with fragments of glass containers, bottles, glasses, window panes and some slag. The recent excavation which took place in 2004–2006 in the Palau Cervero , 4 Cisneros square also s…