Discussion

Alícia CalmellPla general de la paret d'entrada al Saló de Cent. S'observen bancs, vidrieres, làmpades, domassos, arcs i el sostre de fusta. Destaquen les escultures de Jaume I (esquerra) i Sant Jordi (dreta) cobertes per pinacles de fusta

Measurement and modification of forces between lecithin bilayers

We probe in two different ways the competing attractive and repulsive forces that create lamellar arrays of the phospholipid lecithin when in equilibrium with pure water. The first probe involves the addition of low molecular weight solutes, glucose and sucrose, to a system where the phospholipid is immersed in a large excess of water. Small solutes can enter the aqueous region between bilayers. Their effect is first to increase and then to decrease the separation between bilayers as sugar concentration increases. We interpret this waxing and waning of the lattice spacing in terms of the successive weakening and strengthening of the attractive van der Waals forces originally responsible for creation of a stable lattice. The second probe is an "osmotic stress method," in which very high molecular weight neutral polymer is added to the pure water phase but is unable to enter the multilayers. The polymer competes for water with the lamellar lattice, and thereby compresses it. From the resulting spacing (determined by X-ray diffraction) and the directly measured osmotic pressure, we find a force vs. distance curve for compressing the lattice (or, equivalently, the free energy of transfer to bulk water of water between bilayers. This method reveals a very strong, exponentially varying "hydration force" with a decay distance of about 2 A

Adolf Prag (1906–2004)

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Electron Microscopic Studies of the Virus of Human Warts*1From the Department of Pathology, University of California School of Medicine, San Francisco and the Virus Laboratory, Berkeley, California.

Servei d'Elements UrbansPrimer pla d'una reixa interceptora de barres inclinades en calçada

Cut elimination for a simple formulation of epsilon calculus

AbstractA simple cut elimination proof for arithmetic with the epsilon symbol is used to establish the termination of a modified epsilon substitution process. This opens a possibility of extension to much stronger systems

Iterated extended ultrapowers and supercompactness without choice

AbstractWorking in ZF + DC with no additional use of the axiom of choice, we show how to iterate the extended ultrapower construction of Spector (1988, 1991). This generalizes the technique of iterated ultrapowers to choiceless set theory. As an application, we prove the following theorem: Assume V = LU[Pκ(λ)] + “κ is λ-supercompact with normal ultrafilter U” + DC. Then for every sufficiently large regular cardinal ρ, there exists a set-generic extension V[G] of the universe in which there exists for some σ a set S ⊆ Pρ(σ) for which one can define an elementary embedding j mapping V to LD[S], where D is the filter in V[G] generated by the closed unbounded filter (according to V) on Pρ(σ). Moreover, we have j(κ) = ρ, j(λ) = σ, j(Pκ(λ)) = S (which is Pρ(σ) according to LD[S]), and j(itU) = D ∩ LD[S] i s a normal ultrafilter in LD[S] on Pρ(σ)

Business-related knowledge base of vascular surgeons

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TCT-132 Abstract Withdrawn

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Permission request

Plànol general de la plaça de Salvador Seguí.Digitalitzat per Tecnodo

RNA Processing: Wilms' tumour — the splicing connection?

AbstractMajor isoforms of WT1 — products of the tumour suppressor gene WT1, implicated in predisposition to Wilms' tumour — may preferentially interact with splicing factors, suggesting a role for WT1 in RNA processing