60 research outputs found

    Two-dimensional Copolymers and Multifractality: Comparing Perturbative Expansions, MC Simulations, and Exact Results

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    We analyze the scaling laws for a set of two different species of long flexible polymer chains joined together at one of their extremities (copolymer stars) in space dimension D=2. We use a formerly constructed field-theoretic description and compare our perturbative results for the scaling exponents with recent conjectures for exact conformal scaling dimensions derived by a conformal invariance technique in the context of D=2 quantum gravity. A simple MC simulation brings about reasonable agreement with both approaches. We analyse the remarkable multifractal properties of the spectrum of scaling exponents.Comment: 5 page

    Scaling in DNA unzipping models: denaturated loops and end-segments as branches of a block copolymer network

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    For a model of DNA denaturation, exponents describing the distributions of denaturated loops and unzipped end-segments are determined by exact enumeration and by Monte Carlo simulations in two and three dimensions. The loop distributions are consistent with first order thermal denaturation in both cases. Results for end-segments show a coexistence of two distinct power laws in the relative distributions, which is not foreseen by a recent approach in which DNA is treated as a homogeneous network of linear polymer segments. This unexpected feature, and the discrepancies with such an approach, are explained in terms of a refined scaling picture in which a precise distinction is made between network branches representing single stranded and effective double stranded segments.Comment: 8 pages, 8 figure

    Scaling behaviour of lattice animals at the upper critical dimension

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    We perform numerical simulations of the lattice-animal problem at the upper critical dimension d=8 on hypercubic lattices in order to investigate logarithmic corrections to scaling there. Our stochastic sampling method is based on the pruned-enriched Rosenbluth method (PERM), appropriate to linear polymers, and yields high statistics with animals comprised of up to 8000 sites. We estimate both the partition sums (number of different animals) and the radii of gyration. We re-verify the Parisi-Sourlas prediction for the leading exponents and compare the logarithmic-correction exponents to two partially differing sets of predictions from the literature. Finally, we propose, and test, a new Parisi-Sourlas-type scaling relation appropriate for the logarithmic-correction exponents.Comment: 10 pages, 5 figure

    Noisy random resistor networks: renormalized field theory for the multifractal moments of the current distribution

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    We study the multifractal moments of the current distribution in randomly diluted resistor networks near the percolation treshold. When an external current is applied between to terminals xx and xx^\prime of the network, the llth multifractal moment scales as MI(l)(x,x)xxψl/νM_I^{(l)} (x, x^\prime) \sim | x - x^\prime |^{\psi_l /\nu}, where ν\nu is the correlation length exponent of the isotropic percolation universality class. By applying our concept of master operators [Europhys. Lett. {\bf 51}, 539 (2000)] we calculate the family of multifractal exponents {ψl}\{\psi_l \} for l0l \geq 0 to two-loop order. We find that our result is in good agreement with numerical data for three dimensions.Comment: 30 pages, 6 figure

    Sex Segregation and Salary Structure in Academia

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    This article reports a study of aggregate unit salary levels, within a major research university. We analyze these salary levels, as they are influenced by unit sex composition, and modified by unit attainment levels—where unit refers to the departments, colleges and schools, and other academic divisions of the university. We investigate three central issues of sex and salary, previously overlooked in salary studies of academic employees: Do high proportions of women depress men's unit salary levels ("competition" hypothesis)? Are women's salary levels higher in male-dominated, and lower in female-dominated, units ("concentration" hypothesis)? Are men salary-compensated for working with women ("compensation" hypothesis)? The findings support none of these hypotheses. Rather, the relationship between unit sex composition and salary rests upon the connection between units' composition and attainment levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69126/2/10.1177_073088848100800103.pd

    Measurement of time-dependent CP violation in B-0 - eta \u27 K-0 decays

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    The Physics of the B Factories

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    "Kill the Damn Masters!" : Narratives of Religious War and Social Conflict in Kvistbro parish 1843

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    This thesis examines narratives of the events called ”The War of Religion in Kvistbro”, a violent turmoil that erupted in Närke, Sweden 1843. The events involved persons connected to the Shouter Movement, a pietist inspired revivalist movement, and governmental officials who were ordered to arrest a preacher.A narrative analysis based on a model inspired by Labov and Chatman, is used for examining contemporary local newspaper Nerikes Allehanda's and the revivalist historian E. J.Ekman's narrations of the events. The theoretical framework of this thesis is founded on Charles Tilly's theory of collective violence, and James C Scott's theories of hidden transcripts and weapons of the weak.The results of the analysis indicates that there are three main understandings of the events within the empiric material: a religious framing, a medical framing, and a socio-political reading. The socio-political reading of the narratives implies that the concepts medicine as control, social antagonism, and gender-coded aspects of conflict, emerge from the material
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