10,000 publications from this institution
Adipose tissue physiology plays an important role in the development of several obesity-related disorders. Dietary restriction regimens, i.e., daily calorie restriction (CR) or alternate-day fasting (ADF), have been shown to decrease the risk of these disorders. Whether changes in adipose mass or physiology are required for the beneficial effects of CR or ADF is an important question. Accordingly, this review summarizes the effects of CR and ADF regimens on parameters of adipose physiology, i.e., adipose tissue morphology, triglyceride metabolism, and adipokine release, and attempts to link these changes to indicators of chronic disease risk.
The International Monetary Fund is a controversial institution whose interventions regularly provoke passionate reactions. We will argue that there is an important role for the IMF in helping to solve information, commitment, and coordination problems with significant implications for the stability of national economies and the international monetary and financial system. In executing these functions, the effectiveness of the IMF, like that of a football referee, depends on whether the players see it as competent and impartial. We will argue that the Fund’s perceived competence and impartiality, and hence its effectiveness, are limited by its failure to meet four challenges—concerning the quality of it's surveillance (of individual countries, groups of countries, and the global system); the relevance of conditionality in loan contracts; the utility of the Fund’s approach to debt problems; and the Fund’s failure to adopt a system of governance that gives appropriate voice to different stakeholders. These problems of legitimacy will have to be addressed in order for the IMF to play a more effective role in the 21st century.
Linear copolymers that have pendant coumarin-2 and coumarin-343 chromophores were prepared as analogues to previously synthesized light-harvesting dendrimers. The chromophore ratios within these polymers were maintained similar to those of the various generation dendrimers to investigate the effect of polymer architecture on the energy-transfer efficiency between the coumarin-2 donors and coumarin-343 acceptors. Both physical and photophysical properties of these polymers were analyzed and compared to those of the analogous dendrimers. Energy-transfer efficiencies were relatively high in the polymers; however, deleterious excimer formation between the coumarin-343 chromophores diminished the quantum yield of fluorescence of the polymers when compared to the analogous dendrimers. Overall, it was found that the ultimate performance of the dendritic light-harvesting antennae was superior to that of the polymeric analogues, but the polymers were more practical in terms of synthetic accessibility. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1366–1373, 2001
The objectives of this study were to investigate the influence of ethylene addition on the hydrogenation of CO over Ru/SiO/sub 2/ and to compare the product distribution obtained with those for CO hydrogenation in the absence of ethylene and ethylene homologation in the absence of CO. To enable identification of the source of carbon in the products, /sup 13/C-labeled CO and unlabeled C/sub 2/H/sub 4/ were used. Products were analyzed by isotope-ratio gas chromatography-mass spectrometry. Among the issues investigated were the influence of ethylene addition on the reactions of CO and the participation of ethylene in processes of hydrocarbon chain initiation and growth. The influence of ethylene addition on methane formation was also examined.
By exploiting the new concepts of CA characteristic functions and their associated attractor time-τ maps, a complete characterization of the long-term time-asymptotic behaviors of all 256 one-dimensional CA rules are achieved via a single "probing" random input signal. In particular, the graphs of the time-1 maps of the 256 CA rules represent, in some sense, the generalized Green's functions for Cellular Automata. The asymptotic dynamical evolution on any CA attractor, or invariant orbit, of 206 (out of 256) CA rules can be predicted precisely, by inspection. In particular, a total of 112 CA rules are shown to obey a generalized Bernoulli σ τ -shift rule, which involves the shifting of any binary string on an attractor, or invariant orbit, either to the left, or to the right, by up to 3 pixels, and followed possibly by a complementation of the resulting bit string. The most intriguing result reported in this paper is the discovery that the four Turing-universal rules [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], and only these rules, exhibit a 1/f power spectrum.
A new physical principle has emerged to produce record voltages and efficiencies in photovoltaic cells, "luminescence extraction." This is exemplified by the mantra "a good solar cell should also be a good LED." Luminescence extraction is the escape of internal photons out of the front surface of a solar cell. Basic thermodynamics says that the voltage boost should be related to concentration ratio, C, of a resource by ΔV=(kT/q)ln{C}. In light trapping, (i.e. when the solar cell is textured and has a perfect back mirror) the concentration ratio of photons C={4n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> }, so one would expect a voltage boost of Δν=kT ln{4n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> } over a solar cell with no texture and zero back reflectivity, where n is the refractive index. Nevertheless, there has been ambiguity over the voltage benefit to be expected from perfect luminescence extraction. Do we gain an open circuit voltage boost of ΔV=(kT/q)ln{n <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> }, ΔV=(kT/q)ln{2n <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> }, or ΔV=(kT/q)ln{4n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> }? What is responsible for this voltage ambiguity ΔV=(kT/q)ln{4}=36mVolts? We show that different results come about, depending on whether the photovoltaic cell is optically thin or thick to its internal luminescence. In realistic intermediate cases of optical thickness the voltage boost falls in between; ln{n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> }qΔV/kT)<;ln{4n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> }.
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The goals of this paper are to briefly describe experimental methods that are used to measure SO2 dry deposition, and to discuss the physical, biological and chemical processes that control SO2 deposition fluxes over vegetation and to describe how these fluxes are modelled. The predominant pathway for gaseous SO2 uptake to dry vegetation is via turbulent transfer through the atmosphere surface boundary layer and molecular diffusion through the leaf laminar boundary layer and the stomata. The soil surface is a significant, but weaker sink for sulphur, especially when frozen or covered with snow. The appreciable solubility of SO2 causes its uptake to be enhanced greatly in the presence of moisture on leaves and the soil. The aqueous uptake of SO2, however, causes the pH of a solution to decrease which in turn produces a reduction in the solubility of SO2. Neutralising species (ammonia, inner plant species) may cancel this reduction. A method is proposed to estimate local scale dry deposition fluxes of SO2 in Europe. The method combines long-range transport modelling results, land use and surface specific data and an inferential approach.
