826 research outputs found

    From Social Control to Financial Economics: The Linked Ecologies of Economics and Business in Twentieth Century America

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    This article draws on historical material to examine the co-evolution of economic science and business education over the course of the twentieth century, showing that fields evolve not only through internal struggles but also through struggles taking place in adjacent fields. More specifically, we argue that the scientific strategies of business schools played an essential—if largely invisible and poorly understood—role in major transformations in the organization and substantive direction of social-scientific knowledge, and specifically economic knowledge, in twentieth century America. We use the Wharton School as an illustration of the earliest trends and dilemmas (ca. 1900–1930), when business schools found themselves caught between their business connections and their striving for moral legitimacy in higher education. Next, we look at the creation of the Carnegie Tech Graduate School of Industrial Administration after World War II. This episode illustrates the increasingly successful claims of social scientists, backed by philanthropic foundations, on business education and the growing appeal of “scientific” approaches to decision-making and management. Finally, we argue that the rise of the Graduate School of Business at the University of Chicago from the 1960s onwards (and its closely related cousin at the University of Rochester) marks the decisive ascendancy of economics, and particularly financial economics, in business education over the other behavioral disciplines. We document the key role of these institutions in diffusing “Chicago-style” economic approaches—offering support for deregulatory policies and popularizing narrowly financial understandings of the firm—that sociologists have described as characteristic of the modern neo liberal regime

    Field Theory And Second Renormalization Group For Multifractals In Percolation

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    The field-theory for multifractals in percolation is reformulated in such a way that multifractal exponents clearly appear as eigenvalues of a second renormalization group. The first renormalization group describes geometrical properties of percolation clusters, while the second-one describes electrical properties, including noise cumulants. In this context, multifractal exponents are associated with symmetry-breaking fields in replica space. This provides an explanation for their observability. It is suggested that multifractal exponents are ''dominant'' instead of ''relevant'' since there exists an arbitrary scale factor which can change their sign from positive to negative without changing the Physics of the problem.Comment: RevTex, 10 page

    Direct fiber comb stabilization to a gas-filled hollow-core photonic crystal fiber

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    We have isolated a single tooth from a fiber laser-based optical frequency comb for nonlinear spectroscopy and thereby directly referenced the comb. An 89 MHz erbium fiber laser frequency comb is directly stabilized to the P(23) (1539.43 nm) overtone transition of [superscript]12C[subscript]2H[subscript]2 inside a hollow-core photonic crystal fiber. To do this, a single comb tooth is isolated and amplified from 20 nW to 40 mW with sufficient fidelity to perform saturated absorption spectroscopy. The fractional stability of the comb, ~7 nm away from the stabilized tooth, is shown to be 6 × 10[superscript]−12 at 100 ms gate time, which is over an order of magnitude better than that of a comb referenced to a GPS-disciplined Rb oscillator

    Bond-charge Interaction in the extended Hubbard chain

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    We study the effects of bond-charge interaction (or correlated hopping) on the properties of the extended ({\it i.e.,} with both on-site (UU) and nearest-neighbor (VV) repulsions) Hubbard model in one dimension at half-filling. Energy gaps and correlation functions are calculated by Lanczos diagonalization on finite systems. We find that, irrespective of the sign of the bond-charge interaction, XX, the charge--density-wave (CDW) state is more robust than the spin--density-wave (SDW) state. A small bond-charge interaction term is enough to make the differences between the CDW and SDW correlation functions much less dramatic than when X=0X=0. For X=tX=t and fixed V<2tV<2t (tt is the uncorrelated hopping integral), there is an intermediate phase between a charge ordered phase and a phase corresponding to singly-occupied sites, the nature of which we clarify: it is characterized by a succession of critical points, each of which corresponding to a different density of doubly-occupied sites. We also find an unusual slowly decaying staggered spin-density correlation function, which is suggestive of some degree of ordering. No enhancement of pairing correlations was found for any XX in the range examined.Comment: 10 pages, 7 PostScript figures, RevTeX 3; to appear in Phys Rev

    Results of D-IMPACT

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    Summary Aims:  Diagnosis IMprovement in PrimAry Care Trial (D-IMPACT) was a prospective, multicentre epidemiological study in three European countries to identify the optimal subset of simple tests applied in primary care to diagnose benign prostatic hyperplasia (BPH) in men who spontaneously present with lower urinary tract symptoms (LUTS). Methods:  Consecutive male patients aged ≥ 50 years who spontaneously attended their regular general practitioner (GP) office with LUTS were eligible for inclusion if they had not previously undergone BPH diagnostic tests or received treatment for BPH. Patients were assessed on three occasions, twice by their regular GP (visits 1 and 2) and once by a urologist (visit 3). The diagnostic accuracy of each variable was determined using the urologists' final BPH diagnosis (at visit 3) as gold-standard. Independent variables analysed were as follows: age; BPH diagnosis performed by GP in visit 1 (yes/no); probability of BPH diagnosis assessed by GP in visit 1; urinalysis (normal/abnormal); prostate-specific antigen (PSA); International Prostate Symptom Score (IPSS); diagnosis of BPH performed by GP in visit 2 (yes/no); and probability of BPH diagnosis assessed by GP in visit 2. Statistically significant variables (p 1.5 ng/ml and prostate volume ≥ 30 cm3). Among the independent variables analysed, only age, IPSS and PSA showed a statistically significant relationship with BPH diagnosis. In a logistic regression model including age, IPSS, PSA and probability of BPH (based on physical examination and symptoms), positive predictive value (PPV) was 77.1%. Exclusion of BPH probability resulted in a PPV of 75.7%. Conclusions:  A diagnostic algorithm including only objective variables (age, IPSS and PSA), easily implemented in any GP office, allows GPs to accurately diagnose BPH in approximately three-quarters of patients spontaneously reporting LUTS

    In-situ surface technique analyses and ex-situ characterization of Si1-xGex epilayers grown on Si(001)-2 ×1 by molecular beam epitaxy

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    Si1-xGex epilayers grown by Molecular Beam Epitaxy on Si(001) at 400 ○C have been analyzed in-situ by surface techniques such as X-ray and Ultraviolet Photoelectron Spectroscopies (XPS and UPS), Low Energy Electron Diffraction (LEED) and photoelectron diffraction (XPD). The Ge surface concentrations (x) obtained from the ratios of Ge and Si core level intensities are systematically higher than those obtained by the respective evaporation fluxes. This indicates a Ge enrichment in the first overlayers confirmed by Ge-like UPS valence band spectra. The structured crystallographic character of the epilayers is ascertained by LEED and XPD polar scans in the (100) plane since the Ge Auger LMM and the Si 2p XPD intensity patterns from the Si1-xGex epilayers are identical to those of the Si substrate. The residual stress in the epilayer is determined by ex-situ X-ray diffraction (XRD) which also allows, as Rutherford Back Scattering (RBS), Ge concentration determinations

    Mechanism of CDW-SDW Transition in One Dimension

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    The phase transition between charge- and spin-density-wave (CDW, SDW) phases is studied in the one-dimensional extended Hubbard model at half-filling. We discuss whether the transition can be described by the Gaussian and the spin-gap transitions under charge-spin separation, or by a direct CDW-SDW transition. We determine these phase boundaries by level crossings of excitation spectra which are identified according to discrete symmetries of wave functions. We conclude that the Gaussian and the spin-gap transitions take place separately from weak- to intermediate-coupling region. This means that the third phase exists between the CDW and the SDW states. Our results are also consistent with those of the strong-coupling perturbative expansion and of the direct evaluation of order parameters.Comment: 5 pages(REVTeX), 5 figures(EPS), 1 table, also available from http://wwwsoc.nacsis.ac.jp/jps/jpsj/1999/p68a/p68a42/p68a42h/p68a42h.htm

    Impermeability effects in three-dimensional vesicles

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    We analyse the effects that the impermeability constraint induces on the equilibrium shapes of a three-dimensional vesicle hosting a rigid inclusion. A given alteration of the inclusion and/or vesicle parameters leads to shape modifications of different orders of magnitude, when applied to permeable or impermeable vesicles. Moreover, the enclosed-volume constraint wrecks the uniqueness of stationary equilibrium shapes, and gives rise to pear-shaped or stomatocyte-like vesicles.Comment: 16 pages, 7 figure

    The National Pediatric Surgery Simulation Program in France: A tool to develop resident training in pediatric surgery

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    BACKGROUND/PURPOSE: To implement resident curriculum in France based on theoretical teaching and bed side training, the national council known as the "Collège Hospitalier et Universitaire de Chirurgie Pédiatrique" examined the relevance and feasibility of systematically introducing simulation program in the pediatric surgery resident training. MATERIAL AND METHODS: A national simulation training program was developed and took place in a 2-day session organized in 7 simulation centers in France. The program included technical (laparoscopic/suturing technique on low-fidelity models) and nontechnical (6 scenarios for standardized consultation, and a team work scenario based on errors prevention in the operative room) skills. Evaluation of the program (Likert scale from 1 (bad) to 5 (excellent) and notation on 20 points) concerned trainees and trainers. RESULTS: 40 residents (95% of all pediatric surgery French residents) attended with a ratio of trainees/trainer of ½. The training objectives earned a score of 4.46/5. The pedagogical value of the seminar scored 4.7/5, teaching quality 17.95/20, and the overall seminar score was 17.35/20. CONCLUSION: This program, unique nationally, was assessed very favorably by the participating residents and by the involved trainers. To our knowledge, it represents the first mandatory national simulation training program included within a surgical training model. LEVEL OF EVIDENCE: Level IV

    Elastic deformation of a fluid membrane upon colloid binding

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    When a colloidal particle adheres to a fluid membrane, it induces elastic deformations in the membrane which oppose its own binding. The structural and energetic aspects of this balance are theoretically studied within the framework of a Helfrich Hamiltonian. Based on the full nonlinear shape equations for the membrane profile, a line of continuous binding transitions and a second line of discontinuous envelopment transitions are found, which meet at an unusual triple point. The regime of low tension is studied analytically using a small gradient expansion, while in the limit of large tension scaling arguments are derived which quantify the asymptotic behavior of phase boundary, degree of wrapping, and energy barrier. The maturation of animal viruses by budding is discussed as a biological example of such colloid-membrane interaction events.Comment: 14 pages, 9 figures, REVTeX style, follow-up on cond-mat/021242
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