Repression, defined

The hydrocarbon feed must contain sufficient steam to avoid carbon formation on the catalyst. The steam-to-carbon ratio is defined as moles of steam per mole of carbon in the hydrocarbon. The steam-to-carbon ratios are about 3.0 for hydrocarbon feedstocks but lower values can be used for some feedstocks. Carbon formation is more likely with heavier feedstocks. An alkali-based catalyst can be used to repress carbon formation. 

Various groups of workers have attempted to determine the k, by the use of common-ion salts so as to repress the dissociation of the ion-pairs at the growing end. In this context the two types of initiator pose different, but related, problems. If the initiator is a protonic acid AH, as in most of the stopped-flow experiments, the greatest part of the AH does not participate in the initiation (see Section 4.3.2). In these systems, therefore, conjugate ions A2H can be formed from the added salt Bs+A" and therefore the effective [A ] < [Bs+A ]0. In the usual plots [Equation (23) below] of kp (defined in Section 2.5.3) versus [Bs+A ]01/2 this uncertainty will not affect the intercept k, at [Bs+A ]0 1/2 = 0, but it will make the slope, from which the kp can be found, smaller, so that the resulting kp will be an underestimate. 

Heintzen C, Loros JJ, Dunlap JC 2001 The PAS protein VIVID defines a clock-associated feedback loop that represses light input, modulates gating, and regulates clock resetting. Cell 104 453-464... 

Be able to define constitutive enzymes, inducible enzymes, enzyme repression, coordinate repression, and derepression. 

Repression of our essence was instituted in the enculturation process and for many people is now very thorough. As a vital child, you could not have walked by a strange animal on the sidewalk without stopping to look and wonder. As an adult, chances are you don t even feel the urge to look. You re too important you have to get to work. The widespread repression of most of our native curiosity, so that you are only allowed to be curious about things the culture defines as important, is one of the most horrible things about enculturation. 

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