2,520 research outputs found

    Mirror Symmetry for open r-spin invariants

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    We show that a generating function for open rr-spin enumerative invariants produces a universal unfolding of the polynomial xrx^r. Further, the coordinates parametrizing this universal unfolding are flat coordinates on the Frobenius manifold associated to the Landau-Ginzburg model (C,xr)(\mathbb{C},x^r) via Saito-Givental theory. This result provides evidence for the same phenomenon to occur in higher dimension, proven in a sequel paper.Comment: 11 page

    Pole Term and Gauge Invariance in Deep Inelastic Scattering

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    In this paper we reconcile two contradictory statements about deep inelastic scattering (DIS) in manifestly covariant theories: (i) the scattering must be gauge invariant, even in the deep inelastic limit, and (ii) the pole term (which is not gauge invariant in a covariant theory) dominates the scattering amplitude in the deep inelastic limit. An ``intermediate'' answer is found to be true. We show that, at all energies, the gauge dependent part of the pole term cancels the gauge dependent part of the rescattering term, so that both the pole and rescattering terms can be separately redefined in a gauge invariant fashion. The resulting, redefined pole term is then shown to dominate the scattering in the deep inelastic limit. Details are worked out for a simple example in 1+1 dimensions.Comment: 10 figure

    A Randomized Trial of Realignment Therapy for Treatment of Medial Tibiofemoral Osteoarthritis

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    Objectives: The objective of this 30-week randomized crossover trial was to determine whether a multi-modal realignment therapy would be successful in relieving pain and improving function among persons with medial tibiofemoral OA. METHODS: We conducted a double blind, randomized crossover trial of a multi-modal realignment therapy for persons with medial tibiofemoral OA. Trial participants met ACR criteria for OA with knee pain, aching or stiffness on most days of the past month and radiographic evidence of a definite osteophyte with predominant medial tibiofemoral OA. We tested two different treatments: A) CONTROL TREATMENT consisting of a neutral knee brace (no valgus angulation), flat unsupportive foot orthoses, and shoes with a flexible midsole; and B) ACTIVE TREATMENT consisting of a valgus knee brace, customized neutral foot orthoses, and shoes designed for motion control. For each subject, the trial lasted 30 weeks, including 12 weeks each of active and control treatment separated by a 6-week washout period. The primary outcome of the linear regression model was change in knee pain and function as assessed by the WOMAC Osteoarthritis Index. RESULTS: 80 participants with medial tibiofemoral OA were randomized. Their mean age was 62 years, mean BMI was 34 kg/m2 and mean WOMAC pain score was 9.2 (0-20 scale). There was no evidence of a carryover effect. The regression model demonstrated that the mean difference in pain between the active and control treatments was -1.82 units (95% confidence interval: -3.05 to -0.60 [p=0.004]) on the WOMAC pain scale, indicating a small, but statistically significant decrease in pain with the multi-modal active treatment. For WOMAC function the realignment intervention had a non-significant effect on function with a -2.90 unit decrease (95% CI -6.60 to 0.79) compared with the control condition (p=0.12). CONCLUSION: Multi-modal realignment therapy decreases pain in persons with medial tibiofemoral OA

    Mean Field Dynamics in Non-Abelian Plasmas from Classical Transport Theory

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    Based on classical transport theory, we present a general set of covariant equations describing the dynamics of mean fields and their statistical fluctuations in a non-Abelian plasma in or out-of-equilibrium. A procedure to obtain the collision integrals for the Boltzmann equation from the microscopic theory is described. As an application, we study a hot non-Abelian plasma close to equilibrium, where the fluctuations are integrated out explicitly. For soft fields, and at logarithmic accuracy, we obtain B\"odeker's effective theory.Comment: 4 pages, revtex, no figures. Typo removed, a reference updated, version as to appear in Phys. Rev. Let

    Heated nuclear matter, condensation phenomena and the hadronic equation of state

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    The thermodynamic properties of heated nuclear matter are explored using an exactly solvable canonical ensemble model. This model reduces to the results of an ideal Fermi gas at low temperatures. At higher temperatures, the fragmentation of the nuclear matter into clusters of nucleons leads to features that resemble a Bose gas. Some parallels of this model with the phenomena of Bose condensation and with percolation phenomena are discussed. A simple expression for the hadronic equation of state is obtained from the model.Comment: 12 pages, revtex, 1 ps file appended (figure 1

    A remark on non-Abelian classical kinetic theory

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    It is known that non-Abelian classical kinetic theory reproduces the Hard Thermal/Dense Loop (HTL/HDL) effective action of QCD, obtained after integrating out the hardest momentum scales from the system, as well as the first higher dimensional operator beyond the HTL/HDL level. We discuss here its applicability at still higher orders, by comparing the exact classical effective action obtained in the static limit, with the 1-loop quantum effective potential. We remark that while correct types of operators arise, the classical colour algebra reproduces correctly the prefactor of the 4-point function trA04tr A_0^4 only for matter in asymptotically high dimensional colour representations.Comment: 6 page

    A Randomized Trial of Patellofemoral Bracing for Treatment of Patellofemoral Osteoarthritis

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    Purpose The number of effective knee osteoarthritis (OA) interventions, especially those tailored to specific compartmental involvement, are small. The objective of this study was to determine the efficacy of a realigning patellofemoral (PF) brace in improving pain and function among persons with symptomatic lateral PF OA. Method We conducted a double blind, randomized crossover trial of a realigning PF brace for persons with lateral PF OA. Participants had lateral PF OA with anterior knee symptoms on most days of the month, lateral PF joint space narrowing, and radiographic evidence of a definite osteophyte in the PF joint. We compared two treatments: (1) Control treatment consisting of a BioSkin Q Brace with patellar realigning strap removed; and (2) Active treatment consisting of a realigning BioSkin Q Brace with the strap applied. For each participant, the trial lasted 18 weeks, including 6 weeks each of active and control treatment period separated by a 6-week washout period. The order of treatments was randomized. The primary outcome was change in knee pain on the visual analog scale (VAS). Secondary outcomes included WOMAC pain, function, and stiffness. An unstructured correlation matrix for observations within participants was used in generalized estimating equation fitting to derive a linear regression model that expressed the relation between the intervention and change in VAS pain. Results 80 participants (63 F) with a mean age and body mass index of 61 years and 28 kg/m2, respectively, were randomized by order of treatment. A model examining the main effects for change in VAS knee pain (0–100) demonstrated no significant treatment effect (−0.68 VAS units, 95% CI: −6.2, 4.8 units, P = 0.81) and no differential carryover effect. There was also no significant difference between active and control treatments for WOMAC pain, function, or stiffness outcomes. Conclusion The effects of a specific realigning PF brace are not of clinical or statistical significance

    The structure of the graviton self-energy at finite temperature

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    We study the graviton self-energy function in a general gauge, using a hard thermal loop expansion which includes terms proportional to T^4, T^2 and log(T). We verify explicitly the gauge independence of the leading T^4 term and obtain a compact expression for the sub-leading T^2 contribution. It is shown that the logarithmic term has the same structure as the ultraviolet pole part of the T=0 self-energy function. We argue that the gauge-dependent part of the T^2 contribution is effectively canceled in the dispersion relations of the graviton plasma, and present the solutions of these equations.Comment: 27 pages, 6 figure

    Relativistic Structure of the Deuteron: 1.Electro-disintegration and y-scaling

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    Realistic solutions of the spinor-spinor Bethe-Salpeter equation for the deuteron with realistic interaction kernel including the exchange of pi, sigma, omega, rho, eta and delta mesons, are used to systematically investigate relativistic effects in inclusive quasi-elastic electron-deuteron scattering within the relativistic impulse approximation. Relativistic y-scaling is considered by generalising the non relativistic scaling function to the relativistic case, and it is shown that y-scaling does occur in the usual relativistic scaling variable resulting from the energy conservation in the instant form of dynamics. The present approach of y-scaling is fully covariant, with the deuteron being described by eight components, viz. the 3S_1^{++}, 3S_1^{--}, 3D_1^{++}, 3D_1^{--}, 3P_1^{+-}, 3P_1^{-+}, 1P_1^{+-}, 1P_1^{-+} waves. It is demonstrated that if the negative relative energy states 1P_1, 3P_1 are disregarded, the concept of covariant momentum distributions N(p_0,p), with p_0=M_D/2-\sqrt{p^2+m^2}, can be introduced, and that calculations of lectro-disintegration cross section in terms of these distributions agree within few percents with the exact calculations which include the 1P_1, 3P_1 states, provided the nucleon three momentum |p|\<= 1 GeV/c; in this momentum range, the asymptotic relativistic scaling function is shown to coincide with the longitudinal covariant momentum distribution.Comment: 32 LaTeX pages, 18 eps-figures. Final version to appear in Phys. Rev.

    Inclusion of virtual nuclear excitations in the formulation of the (e,e'N)

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    A wave-function framework for the theory of the (e,e'N) reaction is presented in order to justify the use of coupled channel equations in the usual Feynman matrix element. The overall wave function containing the electron and nucleon coordinates is expanded in a basis set of eigenstates of the nuclear Hamiltonian, which contain both bound states as well as continuum states.. The latter have an ingoing nucleon with a variable momentum Q incident on the daughter nucleus as a target, with as many outgoing channels as desirable. The Dirac Eqs. for the electron part of the wave function acquire inhomogeneous terms, and require the use of distorted electron Green's functions for their solutions. The condition that the asymptotic wave function contain only the appropriate momentum Q_k for the outgoing nucleon, which corresponds to the electron momentum k through energy conservation, is achieved through the use of the steepest descent saddle point method, commonly used in three-body calculations.Comment: 30 page
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