The study of PCNA shows that loss of even a single cationic residue can alter the rates of all DNA-linked steps in the loading reaction, as well as movement of PCNA on DNA. These results explain an earlier finding that each of the nine arginines and lysines in human PCNA is essential for polymerase δ processivity. Mutations in the N-terminal domain have greater impact than in the C-terminal domain of PCNA, indicating a positional asymmetry in PCNA-DNA contacts that can influence its functions on DNA.

The study of RFC also shows that removal even one of many cationic residues can alter the rates of DNA-linked steps in the reaction. In addition, we tested the hypothesis that one DNA contact in each RFC subunit can control ATP hydrolysis. Analysis of specific alanine mutants suggest that Arg101 in RFC-D plays a primary role in controlling ATPase activity and Arg88 in RFC-C is important for allowing PCNA•DNA release to end the clamp loading reaction.

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vertices of degree at least *md* has an immersion of *K _{d}*.

Through the conceptual and theoretical frameworks of interculturalism and performance, augmented and supported by indigeneity and music and violence as discursive tangents, the study focuses upon details of musical form, nuance, and contestations and tensions associated with the construction of a particular diasporic Colombianness. Documenting selected key individuals, organizations, and institutions involved with the creation, production, and performance of traditional, neo-traditional, and contemporary new Colombian musics in New York City, I viii discuss the historical and cultural contexts as well as the strategic multiplicities in which the social production of music is embedded and manifested. Focusing upon the contemporary musical practices of the musicians, the dissertation investigates performance, reception, and tropes of self-representation at local, translocal, and transnational and global levels. As new generations of New York Colombian musicians achieve status and garner spaces for new Colombian musics among Latin/o and world musics, I expose transformations within the diasporic Colombian community through its resolute socio-cultural resilience, underlying interculturality, and desire to represent themselves.

]]>In a 2D chaotic flow we measured the translational and rotational dynamics of rods along with the velocity of the carrier flow. Rods are strongly aligned with the stretching direction of the Cauchy-Green deformation tensor.

We report the first three-dimensional measurements of the rotational dynamics of rod-like particles as they are advected in a turbulent fluid flow. Tracer rods preferentially sample the flow since their orientations become correlated with the velocity gradient tensor. The probability distribution of the mean square rotation rate has a long tail which implies the presence of rare events with large rotation rates. Rotation of particles is controlled by small scales of turbulence that are nearly universal, these measurements provide a rich system where experiments can be directly compared with theory and simulations.

In another set of experiments we measured the rotational statistics of neutrally buoyant rods with lengths 2.8 < l/η < 72.9, where η is the Kolmogorov length scale, in turbulence and quantify how their rotation rate depends on length. The mean square rotation rate of rods decreases as the length of the rods increases and for lengths in the inertial range. We derive an scaling of l^{-4/3} for the mean square rotation rate and show that experimental measurements approach this scaling law. In comparison with the randomly oriented rods we see that all rod lengths develop alignment with the velocity gradient of the flow at the length of the rods. We have also measured the correlation time of the Lagrangian autocorrelation of rod rotation rate and find that the correlation time scales as the turn over time of eddies of the size of the rod. Measuring the rotational dynamics of single long rods provides a new way to access the spatial structure of the flow at different length scales.

Beginning from the basic categorical construction of an adjunction, we present Gentzen’s formal derivation system of natural deduction for intuitionistic first-order logic as a categorical graphical language, in which equivalence classes of derivations under the usual relations of convertibility correspond precisely to arrows in a freelygenerated hyperdoctrine categorical semantics. We show that the inference rules and conversion relations on derivations have uniform adjoint-theoretic interpretations, and that the connectives are naturally partitioned into two chiral classes, depending on whether they are characterized by a right or a left adjoint functor. We observe that the adjoint-theoretic descriptions of the non-invertible rules for quantifiers each decompose their natural deduction counterpart into a purely logical rule and a substitution.

By using the same categorical semantics for the formal derivation system of sequent calculus, we are able present a version in which the generic parameters, logic variables and substitutions of logic programming are given first-class status. This in turn allows us to present the operational semantics of SLD-resolution for Horn logic (the logic underlying the programming language Prolog), and that of uniform proof for hereditarily Harrop logic (the first-order fragment of the logic underlying the programming language λ-Prolog), as search strategies in this sequent calculus. We show that the adjoint-theoretic description of the connectives permits a natural extension of the strategy of uniform proof to a syntactically richer language, which we call the language of constructive sequents.

We adopt Andreoli’s idea of focused proof search from linear logic as a search strategy for intuitionistic logic within our sequent system, where it becomes a natural generalization of the strategy of uniform proof. We show that one of the two principles underlying focusing is immediately justified by the adjoint-theoretic properties of the connectives. We compare this focused proof search strategy with a different one proposed by Dyckhoff and Pinto in the context of the input-output semantics of logic programming.

]]>The experimental setup at Morgan’s Lab is designed to generate a neutral atomic or molecular beam, which is then excited with a finely tuned laser to Rydberg states; the highest quantized energy states the electron can be in before ionization. By utilizing the tunable laser we can generate absorption spectra of these Rydberg atoms and molecules. Hidden within these spectra are the quantum and classical dynamics of the electron. This study of Rydberg’s electron dynamics will play a vital role in the analysis and testing of models like semi-classical and quantum theory. This is due to the fact that the Rydberg electron spends very little time near the core of the atom and mostly is present far away from the core, where we can neglect the perturbations of the core. As a result we need not explicitly integrate the motion of the core electrons but rather can treat them as perturbations. The dynamics of such an electron will add proof for existing atomic theories and also find applications in condensed matter physics.

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