4,878 research outputs found

    Comparison of stochastic parameterisation approaches in a single-column model

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    We discuss and test the potential usefulness of single-column models (SCMs) for the testing of stochastic physics schemes that have been proposed for use in general circulation models (GCMs). We argue that although single column tests cannot be definitive in exposing the full behaviour of a stochastic method in the full GCM, and although there are differences between SCM testing of deterministic and stochastic methods, SCM testing remains a useful tool. It is necessary to consider an ensemble of SCM runs produced by the stochastic method. These can be usefully compared to deterministic ensembles describing initial condition uncertainty and also to combinations of these (with structural model changes) into poor man's ensembles. The proposed methodology is demonstrated using an SCM experiment recently developed by the GCSS (GEWEX Cloud System Study) community, simulating transitions between active and suppressed periods of tropical convection

    The Fed and the New Economy

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    This paper seeks to understand the behavior of Greenspan's Federal Reserve in the late 1990s. Some authors suggest that the Fed followed a simple 'Taylor rule,' while others argue that it deviated from such a rule because it recognized that the 'New Economy' permitted an easing of policy. We find that a Taylor rule based on inflation and unemployment does break down in the late 1990s. However, the Fed's behavior appears stable once one accounts for the falling NAIRU of the period. A rule based on inflation and the deviation of unemployment from the NAIRU captures the Fed's behavior through the entire period from 1987 to 2000.

    Productivity Growth and the Phillips Curve

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    We present a model in which workers' aspirations for wage increases adjust slowly to shifts in productivity growth. The model yields a Phillips curve with a new variable: the gap between productivity growth and an average of past wage growth. Empirically, this variable shows up strongly in the U.S. Phillips curve. Including it explains the otherwise puzzling shift in the unemployment-inflation tradeoff since 1995.

    Strong "quantum" chaos in the global ballooning mode spectrum of three-dimensional plasmas

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    The spectrum of ideal magnetohydrodynamic (MHD) pressure-driven (ballooning) modes in strongly nonaxisymmetric toroidal systems is difficult to analyze numerically owing to the singular nature of ideal MHD caused by lack of an inherent scale length. In this paper, ideal MHD is regularized by using a k-space cutoff, making the ray tracing for the WKB ballooning formalism a chaotic Hamiltonian billiard problem. The minimum width of the toroidal Fourier spectrum needed for resolving toroidally localized ballooning modes with a global eigenvalue code is estimated from the Weyl formula. This phase-space-volume estimation method is applied to two stellarator cases

    Behavior and weight correlates of weight-control efforts in Australian women living in disadvantage : the READI study

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    BackgroundWith increasing obesity rates worldwide, more and more people are actively attempting to lose weight or avoid weight gain, but relatively little is known about what specific behaviors comprise these efforts and which, if any, are associated with better weight control over time.MethodsThis paper reports relationships between body weight, weight-control efforts and related behaviors over a three-year period in 1,634 Australian women. The women were purposefully recruited from 80 disadvantaged neighborhoods in Victoria, Australia. Weight loss efforts were categorized as trying to lose weight, trying to prevent weight gain and no weight-control efforts. Behavioral correlates examined included different kinds of physical activity and consumption of a number of specific foods types.Results and discussionSelf-reported body weight at baseline was higher in women trying to lose weight. Frequency of consumption of low energy density foods was positively associated with reported weight-control efforts, as was frequency of reported total and leisure-time physical activity. Longitudinal associations between changes in weight-control efforts and changes in behaviors were consistent with the cross-sectional findings. At three-year follow up, however, weight-control efforts were not associated with change in body weight. More detailed analyses of specific food choices suggested that part of the explanation of no effect of reported weight-control efforts and weight over time might be that people are not as well-informed as they should be about the energy density of some common foods. In particular, those reporting engagement in weight-control efforts reported reducing consumption of carbohydrate-containing foods such as bread and potatoes more than is justified by their energy content, while they reported increasing consumption of some high energy density foods (e.g., cheese and nuts).ConclusionIt is tentatively concluded that women living in disadvantaged neighborhoods understand messages about weight-control (more activity and foods with lower fat and lower energy density) but that some foods eaten more by women engaged in weight control may reduce the effectiveness of these efforts.<br /

    An Analysis of B_s Decays in the Left-Right-Symmetric Model with Spontaneous CP Violation

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    Non-leptonic B_s decays into CP eigenstates that are caused by \bar b -> \bar cc\bar s quark-level transitions, such as B_s -> D_s^+D^-_s, J/psi eta^(') or J/psi phi, provide a powerful tool to search for ``new physics'', as the CP-violating effects in these modes are tiny in the Standard Model. We explore these effects for a particular scenario of new physics, the left-right-symmetric model with spontaneous CP violation. In our analysis, we take into account all presently available experimental constraints on the parameters of this model, i.e. those implied by K- and B-decay observables; we find that CP asymmetries as large as O(40%) may arise in the B_s channels, whereas the left-right-symmetric model favours a small CP asymmetry in the ``gold-plated'' mode B_d -> J/psi K_S. Such a pattern would be in favour of B-physics experiments at hadron machines, where the B_s modes are very accessible.Comment: 12 pages, 5 figure

    Human Health & Water Issues - Micro & Macro: Harmful Algal Blooms, Climate Change & Infectious Diseases Disaster-Related H20 Injuries, Illnesses

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    2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio
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