24,709 research outputs found

    Plankton functional group models – An assessment

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    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

    FCIs and economic activity: Some international evidence

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    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. --

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

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    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

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

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    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. --

    Measurement of tropospheric carbonyl sulfide by microwave spectrometry

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

    The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis

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    BACKGROUND: Some evidence suggests that heart rate variability (HRV) biofeedback might be an effective way to treat anxiety and stress symptoms. To examine the effect of HRV biofeedback on symptoms of anxiety and stress, we conducted a meta-analysis of studies extracted from PubMed, PsycINFO and the Cochrane Library. METHODS: The search identified 24 studies totaling 484 participants who received HRV biofeedback training for stress and anxiety. We conducted a random-effects meta-analysis. RESULTS: The pre-post within-group effect size (Hedges' g) was 0.81. The between-groups analysis comparing biofeedback to a control condition yielded Hedges' g = 0.83. Moderator analyses revealed that treatment efficacy was not moderated by study year, risk of study bias, percentage of females, number of sessions, or presence of an anxiety disorder. CONCLUSIONS: HRV biofeedback training is associated with a large reduction in self-reported stress and anxiety. Although more well-controlled studies are needed, this intervention offers a promising approach for treating stress and anxiety with wearable devices

    Enhancing the Radiative Rate in III-V Semiconductor Plasmonic Core-Shell Nanowire Resonators

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    We investigate the radiative properties of plasmonic core-shell nanowire resonators and, using boundary element method calculations, demonstrate enhanced radiative decay rate by up to 3500 times in nanoscale compound semi-conductor/metal cavities. Calculation of the local density of optical states enables identification of new types of modes in cavities with mode volumes on the order of 10^(-4)(λ/n)^3. These modes dramatically enhance the radiative decay rate and significantly modify the polarization of far-field emission

    Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B

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    We present the results of our investigation, using a Chandra X-ray observation, into the stellar population of the massive star formation region G5.89-0.39, and its potential connection to the coincident TeV gamma-ray source HESSJ1800-240B. G5.89-0.39 comprises two separate HII regions G5.89-0.39A and G5.89-0.39B (an ultra-compact HII region). We identified 159 individual X-ray point sources in our observation using the source detection algorithm \texttt{wavdetect}. 35 X-ray sources are associated with the HII complex G5.89-0.39. The 35 X-ray sources represent an average unabsorbed luminosity (0.3-10\,keV) of 1030.5\sim10^{30.5}\,erg/s, typical of B7-B5 type stars. The potential ionising source of G5.89-0.39B known as Feldt's star is possibly identified in our observation with an unabsorbed X-ray luminosity suggestive of a B7-B5 star. The stacked energy spectra of these sources is well-fitted with a single thermal plasma APEC model with kT\sim5\,keV, and column density NH=2.6×1022_{\rm H}=2.6\times10^{22}\,cm2^{-2} (AV10_{\rm V}\sim 10). The residual (source-subtracted) X-ray emission towards G5.89-0.39A and B is about 30\% and 25\% larger than their respective stacked source luminosities. Assuming this residual emission is from unresolved stellar sources, the total B-type-equivalent stellar content in G5.89-0.39A and B would be 75 stars, consistent with an earlier estimate of the total stellar mass of hot stars in G5.89-0.39. We have also looked at the variability of the 35 X-ray sources in G5.89-0.39. Ten of these sources are flagged as being variable. Further studies are needed to determine the exact causes of the variability, however the variability could point towards pre-main sequence stars. Such a stellar population could provide sufficient kinetic energy to account for a part of the GeV to TeV gamma-ray emission in the source HESSJ1800-240B.Comment: 34 pages, 9 figure

    Nonperturbative screening of the Landau pole

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    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 gg 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
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