Plankton functional group models – An assessment

This Discussant’s Report provides a summary of the discussions that followed presentation of the approaches and ideas described in Thingstad et al. (this volume). The discussions, which addressed aspects of conceptual understanding and parameterization that are relevant to development of ecosystem models capable of emergent behavior at a range of scales, the benefits of functional group modeling, and some of the limitations of this approach, provide insights that are relevant to setting directions for future research efforts. One important point emerging from the discussions was that reconciling the requirements of simplicity versus complexity with the desire to obtain predictive capability is an important area where biogeochemical and ecosystem models can be improved

Note on finite temperature sum rules for vector and axial-vector spectral functions

An updated analysis of vector and axial-vector spectral functions is presented. The resonant contributions to the spectral integrals are shown to be expressible as multiples of 4 pi^2 f_pi^2, encoding the scale of spontaneous chiral symmetry breaking in QCD. Up to order T^2 this behavior carries over to the case of finite temperature.Comment: 10 pages, 2 figure

Linear growth of the trace anomaly in Yang-Mills thermodynamics

In the lattice work by Miller [1,2] and in the work by Zwanziger [3] a linear growth of the trace anomaly for high temperatures was found in pure SU(2) and SU(3) Yang-Mills theories. These results show the remarkable property that the corresponding systems are strong interacting even at high temperatures. We show that within an analytical approach to Yang-Mills thermodynamics this linear rise is obtained and is directly connected to the presence of a temperature-dependent ground state, which describes (part of) the nonperturbative nature of the Yang-Mills system. Our predictions are in approximate agreement with [1,2,3]Comment: 9 pages and 2 figure

Nonperturbative screening of the Landau pole

Based on the trace anomaly for the energy-momentum tensor, an effective theory for the thermodynamics of the deconfining phase, and by assuming the asymptotic behavior to be determined by one-loop perturbation theory we compute the nonperturbative beta function for the fundamental coupling $g$ in SU(2) and SU(3) Yang-Mills theory. With increasing temperature we observe a very rapid approach to the perturbative running. The Landau pole is nonperturbatively screened.Comment: 11 pages, 3 figure

NetCDF model output of the entire state of the surface layer, including simulated dFe dyes, of the circum-Antarctic

Dataset: Antarctic dFe model dyesFor a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/782848NSF Office of Polar Programs (formerly NSF PLR) (NSF OPP) OPP-1643652, NSF Office of Polar Programs (formerly NSF PLR) (NSF OPP) OPP-164361

Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these “designed” composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems

FCIs and economic activity: Some international evidence

A Monetary Conditions Index (MCI), a weighted average of the short-term real interest rate and the real exchange rate, is a commonly used indicator of aggregate demand conditions. In-sample evidence for the US, the euro area, Japan and the UK suggests that a Financial Conditions Index (FCI), also comprising property prices and share prices, would be a better indicator for economic activity than the standard MCI. Out-of sample the FCI also performs better than the MCI, but its overall performance is mixed. An FCI would have predicted the recent economic downturn in Japan and the UK, but not in the US and the euro area. --

Measurement of tropospheric carbonyl sulfide by microwave spectrometry

Microwave rotational spectrometry is used to measure tropospheric carbonyl sulfide. The instrument and techniques for using it are described

The IS curve and the transmission of monetary policy: Is there a puzzle?

In this paper we assess the performance of the New Keynesian IS Curve for the G7 countries. We find that there is an IS puzzle for both the purely backwardlooking as well as for the forward-looking IS curve. The real interest rate does not have a significantly negative effect on the output gap. Based on an extended specification of the IS curve, also including asset prices and monetary aggregates, we are able to restore a significantly negative interest rate effect on aggregate demand in all countries. This finding suggests that a richer specification of the IS curve in empirical work may be necessary in order to obtain an unbiased estimate of the effect of monetary policy on aggregate demand. --