4,755 research outputs found

    Policies And International Integration: Influences On Trade And Foreign Direct Investment

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    This paper assesses the importance of border and non-border policies for global economic integration. The focus is on four widely-advocated policies: removing explicit restrictions to trade and FDI; promoting domestic competition; improving the adaptability of labour markets; and ensuring adequate levels of infrastructure capital. The analysis covers FDI and trade in both goods and services, thus aiming to account for the most important channels of globalisation and dealing with most modes of cross-border services supply. It first describes trends in trade, FDI and the four sets of policies using a large set of structural policy indicators recently constructed by the OECD, including the new summary indicators for FDI-specific regulations described in Golub (2003). It then estimates the impact of policies on bilateral trade and bilateral and multilateral FDI. The results highlight that, despite extensive liberalisation over the past two decades, there is scope for further reducing policy barriers to integration of OECD markets. Remaining barriers have a significant impact on trade and FDI, with anticompetitive domestic regulations and restrictive labour market arrangements estimated to curb integration as much as explicit trade and FDI restrictions. Simulating the removal of such barriers suggests that the quantitative effects of further liberalisation of trade, FDI and domestic product and labour markets on global integration could be substantial

    Far-infrared absorption and the metal-to-insulator transition in hole-doped cuprates

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    By studying the optical conductivity of BSLCO and YCBCO, we show that the metal-to-insulator transition (MIT) in these hole-doped cuprates is driven by the opening of a small gap at low T in the far infrared. Its width is consistent with the observations of Angle-Resolved Photoemission Spectroscopy in other cuprates, along the nodal line of the k-space. The gap forms as the Drude term turns into a far-infrared absorption, whose peak frequency can be approximately predicted on the basis of a Mott-like transition. Another band in the mid infrared softens with doping but is less sensitive to the MIT.Comment: To be published on Physical Review Letter

    Dynamical decoherence of the light induced interlayer coupling in YBa2_{2}Cu3_{3}O6+δ_{6+\delta}

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    Optical excitation of apical oxygen vibrations in YBa2_{2}Cu3_{3}O6+δ_{6+\delta} has been shown to enhance its c-axis superconducting-phase rigidity, as evidenced by a transient blue shift of the equilibrium inter-bilayer Josephson plasma resonance. Surprisingly, a transient c-axis plasma mode could also be induced above Tc_{c} by the same apical oxygen excitation, suggesting light activated superfluid tunneling throughout the pseudogap phase of YBa2_{2}Cu3_{3}O6+δ_{6+\delta}. However, despite the similarities between the above Tc_{c} transient plasma mode and the equilibrium Josephson plasmon, alternative explanations involving high mobility quasiparticle transport should be considered. Here, we report an extensive study of the relaxation of the light-induced plasmon into the equilibrium incoherent phase. These new experiments allow for a critical assessment of the nature of this mode. We determine that the transient plasma relaxes through a collapse of its coherence length rather than its carrier (or superfluid) density. These observations are not easily reconciled with quasiparticle interlayer transport, and rather support transient superfluid tunneling as the origin of the light-induced interlayer coupling in YBa2_{2}Cu3_{3}O6+δ_{6+\delta}.Comment: 27 pages (17 pages main text, 10 pages supplementary), 5 figures (main text

    Analysis of food supplement with unusual raspberry ketone content

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    In recent years food supplement market increased constantly, including slimming products and against obesity. The case of rasberry ketone (RK) is here reported. HPTLC and HPLC-DAD analyses on a marketed product containing raspberry juice evidenced an abnormal quantity of RK, not in accordance with the juice natural content. The reported data confirm the need of adequate controls on marketed food supplements and the necessity of a complete adherence between labelling and real constitution of the product. Practical Applications: Determining the natural origin and assuring the consumers' safety for raspberry-based food supplement

    Magnetic-Field Tuning of Light-Induced Superconductivity in Striped La2x_{2-x}Bax_xCuO4_4

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    Optical excitation of stripe-ordered La2x_{2-x}Bax_xCuO4_4 has been shown to transiently enhance superconducting tunneling between the CuO2_2 planes. This effect was revealed by a blue-shift, or by the appearance of a Josephson Plasma Resonance in the terahertz-frequency optical properties. Here, we show that this photo-induced state can be strengthened by the application of high external magnetic fields oriented along the c-axis. For a 7-Tesla field, we observe up to a ten-fold enhancement in the transient interlayer phase correlation length, accompanied by a two-fold increase in the relaxation time of the photo-induced state. These observations are highly surprising, since static magnetic fields suppress interlayer Josephson tunneling and stabilize stripe order at equilibrium. We interpret our data as an indication that optically-enhanced interlayer coupling in La2x_{2-x}Bax_xCuO4_4 does not originate from a simple optical melting of stripes, as previously hypothesized. Rather, we speculate that the photo-induced state may emerge from activated tunneling between optically-excited stripes in adjacent planes.Comment: 35 pages, 13 figure

    High-temperature optical spectral weight and Fermi liquid renormalization in Bi-based cuprates

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    The optical conductivity and the spectral weight W(T) of two superconducting cuprates at optimum doping, Bi2Sr2-xLaxCuO6 and Bi2Sr2CaCu2O8, have been first measured up to 500 K. Above 300 K, W(T) deviates from the usual T2 behavior in both compounds, even though the zero-frequency extrapolation of the optical conductivity remains larger than the Ioffe-Regel limit. The deviation is surprisingly well described by the T4 term of the Sommerfeld expansion, but its coefficients are enhanced by strong correlation. This renormalization is due to strong correlation, as shown by the good agreement with dynamical mean field calculations.Comment: 5 pages, 3 figures, Physical Review Letters in pres

    N-acetyl-cysteine, a drug that enhances the endogenous activation of group-II metabotropic glutamate receptors, inhibits nociceptive transmission in humans.

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    Emerging research seeking novel analgesic drugs focuses on agents targeting group-II metabotropic glutamate receptors (mGlu2 and mGlu3 receptors). N-Acetylcysteine (NAC) enhances the endogenous activation of mGlu2/3 receptors by activating the glial glutamate:cystine membrane exchanger. Here, we examined whether NAC inhibits nociceptive responses in humans and animals. We tested the effect of oral NAC (1.2 g) on thermal-pain thresholds and laser-evoked potentials in 10 healthy volunteers, according to a crossover, double-blind, placebo-controlled design, and the effect of NAC (100 mg/kg, i.p.) on the tail-flick response evoked by radiant heat stimulation in mice.In healthy subjects, NAC treatment left thermal-pain thresholds unchanged, but significantly reduced pain ratings to laser stimuli and amplitudes of laser-evoked potentials. NAC induced significantly greater changes in these measures than placebo. In the tail-flick test, NAC strongly reduced the nocifensive reflex response to radiant heat. The action of NAC was abolished by the preferential mGlu2/3 receptor antagonist, LY341495 (1 mg/kg, i.p.).Our findings show for the first time that NAC inhibits nociceptive transmission in humans, and does the same in mice by activating mGlu2/3 receptors. These data lay the groundwork for investigating the therapeutic potential of NAC in patients with chronic pain

    Quasiparticle evolution and pseudogap formation in V2O3: An infrared spectroscopy study

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    The infrared conductivity of V2O3 is measured in the whole phase diagram. Quasiparticles appear above the Neel temperature TN and eventually disappear further enhancing the temperature, leading to a pseudogap in the optical spectrum above 425 K. Our calculations demonstrate that this loss of coherence can be explained only if the temperature dependence of lattice parameters is considered. V2O3 is therefore effectively driven from the metallic to the insulating side of the Mott transition as the temperature is increased.Comment: 5 pages, 3 figure

    Pharmacogenetics of Bisphosphonate-associated Osteonecrosis of the Jaw

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    Osteonecrosis of the jaws (ONJ) is a potentially severe disorder that develops in a subgroup of individuals who have used bisphosphonate (BP) medications. Several clinical risk factors have been associated with the risk of ONJ development, but evidence is limited and in most instances ONJ remains an unpredictable adverse drug reaction. Interindividual genetic variability can contribute to explaining ONJ development in a subset of BP users and the discovery of relevant associated gene variants could lead to the identification of individuals at higher risk. No genetic variant has been found to be robustly associated with susceptibility to ONJ

    Optical properties of V2O3 in its whole phase diagram

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    Vanadium sesquioxide V2O3 is considered a textbook example of Mott-Hubbard physics. In this paper we present an extended optical study of its whole temperature/doping phase diagram as obtained by doping the pure material with M=Cr or Ti atoms (V1-xMx)2O3. We reveal that its thermodynamically stable metallic and insulating phases, although macroscopically equivalent, show very different low-energy electrodynamics. The Cr and Ti doping drastically change both the antiferromagnetic gap and the paramagnetic metallic properties. A slight chromium content induces a mesoscopic electronic phase separation, while the pure compound is characterized by short-lived quasiparticles at high temperature. This study thus provides a new comprehensive scenario of the Mott-Hubbard physics in the prototype compound V2O3
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