Renormalization : A number theoretical model

We analyse the Dirichlet convolution ring of arithmetic number theoretic functions. It turns out to fail to be a Hopf algebra on the diagonal, due to the lack of complete multiplicativity of the product and coproduct. A related Hopf algebra can be established, which however overcounts the diagonal. We argue that the mechanism of renormalization in quantum field theory is modelled after the same principle. Singularities hence arise as a (now continuously indexed) overcounting on the diagonals. Renormalization is given by the map from the auxiliary Hopf algebra to the weaker multiplicative structure, called Hopf gebra, rescaling the diagonals.Comment: 15 pages, extended version of talks delivered at SLC55 Bertinoro,Sep 2005, and the Bob Delbourgo QFT Fest in Hobart, Dec 200

Put to the Test: For a New Sociology of Testing

In an age defined by computational innovation, testing seems to have become ubiquitous, and tests are routinely deployed as a form of governance, a marketing device, an instrument for political intervention, and an everyday practice to evaluate the self. This essay argues that something more radical is happening here than simply attempts to move tests from the laboratory into social settings. The challenge that a new sociology of testing must address is that ubiquitous testing changes the relations between science, engineering and sociology: Engineering is today in the very stuff of where society happens. It is not that the tests of 21st Century engineering occur within a social context but that it is the very fabric of the social that is being put to the test. To understand how testing and the social relate today, we must investigate how testing operates on social life, through the modification of its settings. One way to clarify the difference is to say that the new forms of testing can be captured neither within the logic of the field test nor of the controlled experiment. Whereas tests once happened inside social environments, today’s tests directly and deliberately modify the social environment

Insulin inhibition of alpha-adrenergic actions in liver.

The effects of insulin on alpha-agonist (phenylephrine)- and [Arg8]vasopressin-induced Ca2+ and glucose release and mitochondrial Ca2+ fluxes in isolated perfused rat livers were examined. Insulin (6 nM) inhibited the ability of phenylephrine (1 and 0.5 microM) to elicit Ca2+ and glucose release, whereas it was without effect on vasopressin (10 and 2.5 nM) actions. Correspondingly, insulin inhibited the action of phenylephrine to induce a stable increase in mitochondrial Ca2+ uptake, but it did not affect the alteration caused by vasopressin. Phenylephrine and vasopressin caused transient increases in hepatocyte respiration. Insulin inhibited the effect of phenylephrine on this parameter, but not that of vasopressin. Insulin added alone did not alter any of the above parameters. It is concluded from these data that insulin does not alter cellular Ca2+ fluxes and respiration themselves, but selectively inhibits alpha-adrenergic stimulation of these processes. It is proposed that insulin acts either to inhibit binding of alpha-agonists to their specific plasma-membrane receptors or to alter generation and/or degradation of the putative alpha-adrenergic 'second messenger'. If this latter possibility is the case, then the alpha-adrenergic 'second messenger' must be different from the 'second messenger' of vasopressin

Studies on -adrenergic activation of hepatic glucose output. The role of mitochondrial calcium release in -adrenergic activation of phosphorylase in perfused rat liver.

info:eu-repo/semantics/publishe

Hormonal control of hepatic mitochondrial calcium.

info:eu-repo/semantics/publishe

Studies on α-adrenergic activation of hepatic glucose output. The insulin inhibition of α-adrenergic mobilization of mitochondrial calcium in perfused liver.

info:eu-repo/semantics/publishe

Studies on the alpha-adrenergic activation of hepatic glucose output. alpha-Adrenergic activation of phosphorylase by immobilized epinephrine.

In VitroJournal ArticleResearch Support, U.S. Gov't, P.H.S.info:eu-repo/semantics/publishe