1.1. Introduction to conjugacy problems for diffeomorphisms. This is a survey article on the area of global analysis defined by differentiable dynamical systems or equivalently the action (differentiable) of a Lie group G on a manifold M. An action is a homomorphism G->Diff(M) such that the induced map GXM->M is differentiable. Here Diff(M) is the group of all diffeomorphisms of Mand a diffeomorphism is a differentiable map with a differentiable inverse. Everything will be discussed here from the C 00 or C r point of view. All manifolds maps, etc. will be differentiable (C r , l^r^co) unless stated otherwise.In the beginning we will be restricted to the discrete case, G = Z. Here Z denotes the integers, Z + the positive integers. By taking a generator ƒ G Diff(ikT), this amounts to studying diffeomorphisms on a manifold from the point of view of orbit structure. The orbit of %(EM, relative to/, is the subset {f m (x) \m^Z} of M or else the map Z->M which sends m into f m (x). The finite orbits are called periodic orbits and their points, periodic points. Thus xÇ£M is a periodic point if f m (x)=x for some w£Z + , Here m is called a period of x and if m = l, x is Si fixed point. Our problem is to study the global orbit structure, i.e,, all of the orbits on M.The main motivation for this problem comes from ordinary differential equations, which essentially corresponds to G~R> R the reals acting on M. There are two reasons for this leading to the diffeomorphism problem. One is that certain differential equations have cross-sections (see, e.g., [114]) and in this case the qualitative study of the differential equation reduces to the study of an associated diffeomorphism of the cross-section. This is the reason why Poincaré [90] and Birkhoff [19] studied diffeomorphisms of surfaces, I believe there is a second and more important reason for studying the diffeomorphism problem (besides its great natural beauty). That is, the same phenomena and problems of the qualitative theory of ordinary differential equations are present in their simplest form in the diffeomorphism problem. Having first found theorems in the dif-

The generation of cell-mediated immunity against many infectious pathogens involves the production of interleukin-12 (IL-12), a key signal of the innate immune system. Yet, for many pathogens, the molecules that induce IL-12 production by macrophages and the mechanisms by which they do so remain undefined. Here it is shown that microbial lipoproteins are potent stimulators of IL-12 production by human macrophages, and that induction is mediated by Toll-like receptors (TLRs). Several lipoproteins stimulated TLR-dependent transcription of inducible nitric oxide synthase and the production of nitric oxide, a powerful microbicidal pathway. Activation of TLRs by microbial lipoproteins may initiate innate defense mechanisms against infectious pathogens.

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The events leading to transcription of eukaryotic protein-coding genes culminate in the positioning of RNA polymerase II at the correct initiation site. The core promoter, which can extend ~35 bp upstream and/or downstream of this site, plays a central role in regulating initiation. Specific DNA elements within the core promoter bind the factors that nucleate the assembly of a functional preinitiation complex and integrate stimulatory and repressive signals from factors bound at distal sites. Although core promoter structure was originally thought to be invariant, a remarkable degree of diversity has become apparent. This article reviews the structural and functional diversity of the RNA polymerase II core promoter.