7,459 research outputs found

    The Transmission of Price Trends from Consumers to Producers and Tests of Market Power

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    This study examines the competitiveness of four Canadian agricultural industries (eggs, milk, chicken and turkey) using a general equilibrium farm to retail pricing model developed by Wohlgenant (1989). The model generates retail and farm pricing equations that are estimated using maximum likelihood developed by Johansen (1992). The results indicate that in all cases, long-run constant returns is rejected, indicating market power within the Canadian retail to farm marketing sector. The model also finds more cointegrating vectors than predicted by theory, also inconsistent with competitive markets. Results are based on commercial disappearance as a proxy for consumer demand and therefore confounding between uncompetitive markets and quality differences may be indicated. Less ambiguous results would be obtained if consumer expenditures rather than commercial disappearance data were available. Still, results are rather emphatic in rejection of competitive markets in food markets in Canada. More competitive markets are indicated in the United States using similar methods.Market power, food processing, cointegration, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, D41, L66, Q13,

    Anion receptor chemistry: highlights from 2011 and 2012

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    This review covers advances in anion complexation in the years 2011 and 2012. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as self-assembly and molecular architecture, sensing, catalysis and anion transport

    Aminoglycoside-Induced Phosphatidylserine Externalization in Sensory Hair Cells Is Regionally Restricted, Rapid, and Reversible

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    The aminophospholipid phosphatidylserine (PS) is normally restricted to the inner leaflet of the plasma membrane. During certain cellular processes, including apoptosis, PS translocates to the outer leaflet and can be labeled with externally applied annexin V, a calcium-dependent PS-binding protein. In mouse cochlear cultures, annexin V labeling reveals that the aminoglycoside antibiotic neomycin induces rapid PS externalization, specifically on the apical surface of hair cells. PS externalization is observed within ~75 s of neomycin perfusion, first on the hair bundle and then on membrane blebs forming around the apical surface. Whole-cell capacitance also increases significantly within minutes of neomycin application, indicating that blebbing is accompanied by membrane addition to the hair cell surface. PS externalization and membrane blebbing can, nonetheless, occur independently. Pretreating hair cells with calcium chelators, a procedure that blocks mechanotransduction, or overexpressing a phosphatidylinositol 4,5-biphosphate (PIP2)-binding pleckstrin homology domain, can reduce neomycin-induced PS externalization, suggesting that neomycin enters hair cells via transduction channels, clusters PIP2, and thereby activates lipid scrambling. The effects of short-term neomycin treatment are reversible. After neomycin washout, PS is no longer detected on the apical surface, apical membrane blebs disappear, and surface-bound annexin V is internalized, distributing throughout the supranuclear cytoplasm of the hair cell. Hair cells can therefore repair, and recover from, neomycin-induced surface damage. Hair cells lacking myosin VI, a minus-end directed actin-based motor implicated in endocytosis, can also recover from brief neomycin treatment. Internalized annexin V, however, remains below the apical surface, thereby pinpointing a critical role for myosin VI in the transport of endocytosed material away from the periphery of the hair cell

    The nonlinear Bernstein-Schr\"odinger equation in Economics

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    In this paper we relate the Equilibrium Assignment Problem (EAP), which is underlying in several economics models, to a system of nonlinear equations that we call the "nonlinear Bernstein-Schr\"odinger system", which is well-known in the linear case, but whose nonlinear extension does not seem to have been studied. We apply this connection to derive an existence result for the EAP, and an efficient computational method.Comment: 8 pages, submitted to Lecture Notes in Computer Scienc

    Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas

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    Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate

    Azimuthal Asymmetry of Direct Photons in High Energy Nuclear Collisions

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    We show that a sizeable azimuthal asymmetry, characterized by a coefficient v_2, is to be expected for direct photons produced in non-central high energy nuclear collisions. This signal is generated by photons radiated by jets interacting with the surrounding hot plasma. The anisotropy is out of phase by an angle π/2\pi/2 with respect to that associated with the elliptic anisotropy of hadrons, leading to negative values of v_2. Such an asymmetry, if observed, could be a signature for the presence of a quark gluon plasma and would establish the importance of jet-plasma interactions as a source of electromagnetic radiation.Comment: New title. Final versio

    Wind-Tunnel Investigation of the Opening Characteristics, Drag, and Stability of Several Hemispherical Parachutes

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    An investigation has been conducted to determine the opening characteristics of several hemispherical parachutes and to study the influence of the parachute design variables on these opening characteristics. The effects of design variables on the drag and stability characteristics of the parachutes were also evaluated. The tests were made in the Langley 20-foot free-spinning tunnel and in the Langley 300 MPH 7 by 10-foot tunnel

    A shear spectral sum rule in a non-conformal gravity dual

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    A sum rule which relates a stress-energy tensor correlator to thermodynamic functions is examined within the context of a simple non-conformal gravity dual. Such a sum rule was previously derived using AdS/CFT for conformal N=4\mathcal{N} = 4 Supersymmetric Yang-Mills theory, but we show that it does not generalize to the non-conformal theory under consideration. We provide a generalized sum rule and numerically verify its validity. A useful byproduct of the calculation is the computation of the spectral density in a strongly coupled non-conformal theory. Qualitative features of the spectral densities and implications for lattice measurements of transport coefficients are discussed.Comment: 13 pages, 3 figures. v5: Typos in Eq. (60) fixed. v4: References added, matches published version. v3: Minor typographical corrections. v2: References and some discussion in Appendix A have been added; conclusions unchange

    Typical properties of optimal growth in the Von Neumann expanding model for large random economies

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    We calculate the optimal solutions of the fully heterogeneous Von Neumann expansion problem with NN processes and PP goods in the limit NN\to\infty. This model provides an elementary description of the growth of a production economy in the long run. The system turns from a contracting to an expanding phase as NN increases beyond PP. The solution is characterized by a universal behavior, independent of the parameters of the disorder statistics. Associating technological innovation to an increase of NN, we find that while such an increase has a large positive impact on long term growth when NPN\ll P, its effect on technologically advanced economies (NPN\gg P) is very weak.Comment: 8 pages, 1 figur

    High momentum lepton pairs from jet-plasma interactions

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    We discuss the emission of high momentum lepton pairs (p_T>4 GeV) with low invariant masses (M << p_T) in central Au+Au collisions at RHIC (\sqrt{s_{NN}}=200 GeV). The spectra of dileptons produced through interactions of quark and antiquark jets with the quark-gluon plasma (QGP) have been calculated. Annihilation and Compton scattering processes, as well as processes benefitting from collinear enhancement, including Landau-Pomeranchuk-Migdal (LPM) effects, are calculated and convolved with a one dimensional hydrodynamic expansion. The jet-induced contributions are compared to thermal dilepton emission and Drell-Yan processes, and are found to dominate around p_T=4 GeV.Comment: Parallel talk given at QM2006, Shanghai November 2006. 4 pages, 3 figure
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