Getting leverage on inflation with a large photometric redshift survey

We assess the potential of a future large-volume photometric redshift survey to constrain observational inflationary parameters using three large-scale structure observables: the angular shear and galaxy power spectra, and the cluster mass function measured through weak lensing. When used in combination with Planck-like CMB measurements, we find that the spectral index n_s can be constrained to a 1 sigma precision of up to 0.0025. The sensitivity to the running of the spectral index can potentially improve to 0.0017, roughly a factor of five better than the present 1 sigma~constraint from Planck and auxiliary CMB data, allowing us to test the assumptions of the slow-roll scenario with unprecedented accuracy. Interestingly, neither CMB+shear nor CMB+galaxy nor CMB+clusters alone can achieve this level of sensitivity; it is the combined power of all three probes that conspires to break the different parameter degeneracies inherent in each type of observations. We make our forecast software publicly available via download or upon request from the authors.Comment: 22 pages, 6 figures; the forecast software can be downloaded from http://jhamann.web.cern.ch/jhamann/simdata/simdata.tar.g

Dark energy properties from large future galaxy surveys

We perform a detailed forecast on how well a {\sc Euclid}-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We find that the combination of these three probes vastly improves the survey's potential to measure the time evolution of dark energy. In terms of a dark energy figure-of-merit defined as $(\sigma(w_{\mathrm p}) \sigma(w_a))^{-1}$, we find a value of 690 for {\sc Euclid}-like data combined with {\sc Planck}-like measurements of the cosmic microwave background (CMB) anisotropies in a 10-dimensional cosmological parameter space, assuming a $\Lambda$CDM fiducial cosmology. For the more commonly used 7-parameter model, we find a figure-of-merit of 1900 for the same data combination. We consider also the survey's potential to measure dark energy perturbations in models wherein the dark energy is parameterised as a fluid with a nonstandard non-adiabatic sound speed, and find that in an \emph{optimistic} scenario in which $w_0$ deviates by as much as is currently observationally allowed from $-1$, models with $\hat{c}_\mathrm{s}^2 = 10^{-6}$ and $\hat{c}_\mathrm{s}^2 = 1$ can be distinguished at more than $2\sigma$ significance. We emphasise that constraints on the dark energy sound speed from cluster measurements are strongly dependent on the modelling of the cluster mass function; significantly weaker sensitivities ensue if we modify our model to include fewer features of nonlinear dark energy clustering. Finally, we find that the sum of neutrino masses can be measured with a $1 \sigma$ precision of 0.015~eV, (abridged)Comment: 26 pages, 5 figures, matches JCAP versio

Future cosmological sensitivity for hot dark matter axions

We study the potential of a future, large-volume photometric survey to constrain the axion mass $m_a$ in the hot dark matter limit. Future surveys such as Euclid will have significantly more constraining power than current observations for hot dark matter. Nonetheless, the lowest accessible axion masses are limited by the fact that axions lighter than $\sim 0.15$ eV decouple before the QCD epoch, assumed here to occur at a temperature $T_{\rm QCD} \sim 170$ MeV; this leaves an axion population of such low density that its late-time cosmological impact is negligible. For larger axion masses, $m_a \gtrsim 0.15$ eV, where axions remain in equilibrium until after the QCD phase transition, we find that a Euclid-like survey combined with Planck CMB data can detect $m_a$ at very high significance. Our conclusions are robust against assumptions about prior knowledge of the neutrino mass. Given that the proposed IAXO solar axion search is sensitive to $m_a\lesssim 0.2$ eV, the axion mass range probed by cosmology is nicely complementary.Comment: 17 pages, 5 figure

Risikoprämien am europäischen Staatsanleihenmarkt: Neue empirische Erkenntnisse und Überlegungen aus der Sicht der Lebensversicherungsbranche

We study yield spreads between government bonds in the European Monetary Union. This segment of the global fixed income market is of particular importance for insurance companies in Europe. Our empirical research strategy is inspired by Gunay (2020) who has analyzed the relationship between credit and liquidity risk in the United States using Granger causality tests. More specifically, we employ the procedure developed by Toda and Yamamoto (1995) to test for Granger causality among yield spreads in five different member countries of the European Monetary Union (namely Austria, Belgium, France, Italy and Ireland) relative to Germany. We examine interest rate data from bonds with three different maturities (5, 10 and 30 years). Given the importance of long-term bonds as asset class for European life insurers and pension funds, the empirical results from the often ignored market for government bonds with a maturity of 30 years should be of interest. With regard to long-term sovereign debt, there is no evidence for Granger causality among the time series examined here. Consequently, the risk premia required by investors to hold government bonds of one specific member country of the EMU do not help to forecast the risk premia that have to be paid by other countries. Given the structure of their liabilities, this empirical finding should be of high relevance for portfolio and risk managers in the European life insurance industry and in pension funds. With regard to the yield spreads to be observed in the market for 10-year government bonds, there seems to be no clear picture. Focusing on fixed income securities with a maturity of 5 years, there is one very interesting empirical finding. The test results reported here seem to imply that there is unidirectional Granger causality running from the yield spreads in all other four countries to Austria. Given that Austria is a comparably small country which is assumed to be in a fiscally stable position, this result could be interpreted as evidence for credit risk premia as being helpful to forecast liquidity risk premia in the market for medium-term government bonds issued by member states of the European Monetary Union.Diese Studie untersucht Zinsdifferenzen am Markt von Staatsanleihen der Mitgliedsländer der Europäischen Währungsunion. Dieses Segment des globalen Rentenmarktes hat eine besondere Bedeutung für europäische Versicherungsunternehmen. Unsere empirische Studie ist von Gunay (2000) inspiriert, der den Zusammenhang zwischen Kredit- und Liquiditätsrisiko in den Vereinigten Staaten mittels Grangerkausalitätstests untersucht. Genauer gesagt findet hier der Ansatz von Toda und Yamamoto (1995) Anwendung. Untersucht werden die Zinsdifferenzen von fünf Ländern (Österreich, Belgien, Frankreich, Italien und Irland) zu Deutschland. Dabei wird auf drei Laufzeiten (5, 10 und 30 Jahre) geblickt. Der häufig in empirischen Studien ignorierte Markt für Staatsanleihen mit einer Restlaufzeit von 30 Jahren dürfte aufgrund der Struktur der Verbindlichkeiten von besonderem Interesse für Lebensversicherer und Pensionsfonds sein. In diesem Segment des europäischen Staatsanleihemarktes konnten wir keine Hinweise auf Grangerkausalität zwischen den Zinsdifferenzen finden. Die von den hier betrachteten Ländern für ihre Schulden zu zahlenden Risikoprämien helfen somit nicht, die Risikoprämien in den jeweils anderen untersuchten Nationen vorherzusagen. Dieses Ergebnis sollte von hoher Bedeutung für Kapitalanleger und Risikomanager bei europäischen Lebensversicherungen und Pensionsfonds sein. Im Laufzeitsegment 10 Jahre ergibt sich kein klares Bild. Bei den Zinsdifferenzen der Papiere mit einer Laufzeit von 5 Jahren zeigt sich dagegen klar, dass die Risikoprämien in allen anderen Ländern helfen, die Zinsdifferenz von Österreich zu Deutschland vorherzusagen. Da Österreich eher ein kleines Land mit relativ soliden Staatsfinanzen ist, mag dieses Ergebnis ein Hinweis darauf sein, dass das Kreditrisiko in diesem Segment des europäischen Rentenmarktes zur Prognose des Liquiditätsrisikos verwendet werden kann

Leading indicators for US house prices: New evidence and implications for EU financial risk managers

This study draws on machine learning as a means to causal inference for econometric investigation. We utilize the concept of transfer entropy to examine the relationship between the US National Association of Home Builders Index and the S&P CoreLogic Case-Shiller 20 City Composite Home Price Index (SPCS20). The empirical evidence implies that the survey data can help to predict US house prices. This finding extends the results of Granger causality tests performed by Rodriguez Gonzalez et al. in 2018 using a new machine learning approach that methodologically differs from traditional methods in empirical financial research. © 2021 The Authors. European Financial Management published by John Wiley & Sons Ltd

Dividend policy issues in the European pharmaceutical industry: new empirical evidence

This paper examines dividend policy issues in the European pharmaceutical industry. This sector is of particular interest because of the high research and development expenditures and the associated risks characterizing the business models of many firms in this industry. In fact, from the perspective of corporate finance theory, this is a particular challenge for the managers of these corporations that may also have implications for the dividend policy implemented by the firms forming this sector. Moreover, the level of internal financing and litigation risks also seem to be high in the pharmaceutical industry. These facts could also affect the payout policy of the firms. Employing techniques of time series analysis, there is no evidence for dividend signaling and clear evidence for dividend smoothing in the European pharmaceutical industry. Given that dividend increases under certain assumptions can negatively affect the firms' ability to finance new investments in general and research and development projects in particular, these results of our empirical investigations could be described as highly plausible

Spherical collapse of dark energy with an arbitrary sound speed

We consider a generic type of dark energy fluid, characterised by a constant equation of state parameter w and sound speed c_s, and investigate the impact of dark energy clustering on cosmic structure formation using the spherical collapse model. Along the way, we also discuss in detail the evolution of dark energy perturbations in the linear regime. We find that the introduction of a finite sound speed into the picture necessarily induces a scale-dependence in the dark energy clustering, which in turn affects the dynamics of the spherical collapse in a scale-dependent way. As with other, more conventional fluids, we can define a Jeans scale for the dark energy clustering, and hence a Jeans mass M_J for the dark matter which feels the effect of dark energy clustering via gravitational interactions. For bound objects (halos) with masses M >> M_J, the effect of dark energy clustering is maximal. For those with M << M_J, the dark energy component is effectively homogeneous, and its role in the formation of these structures is reduced to its effects on the Hubble expansion rate. To compute quantitatively the virial density and the linearly extrapolated threshold density, we use a quasi-linear approach which is expected to be valid up to around the Jeans mass. We find an interesting dependence of these quantities on the halo mass M, given some w and c_s. The dependence is the strongest for masses lying in the vicinity of M ~ M_J. Observing this M-dependence will be a tell-tale sign that dark energy is dynamic, and a great leap towards pinning down its clustering properties.Comment: 25 pages, 6 figures, matches version published in JCA

Visualization of Abscess Formation in a Murine Thigh Infection Model of Staphylococcus aureus by 19F-Magnetic Resonance Imaging (MRI)

Background: During the last years, 19 F-MRI and perfluorocarbon nanoemulsion (PFC) emerged as a powerful contrast agent based MRI methodology to track cells and to visualize inflammation. We applied this new modality to visualize deep tissue abscesses during acute and chronic phase of inflammation caused by Staphylococcus aureus infection. Methodology and Principal Findings: In this study, a murine thigh infection model was used to induce abscess formation and PFC or CLIO (cross linked ironoxides) was administered during acute or chronic phase of inflammation. 24 h after inoculation, the contrast agent accumulation was imaged at the site of infection by MRI. Measurements revealed a strong accumulation of PFC at the abscess rim at acute and chronic phase of infection. The pattern was similar to CLIO accumulation at chronic phase and formed a hollow sphere around the edema area. Histology revealed strong influx of neutrophils at the site of infection and to a smaller extend macrophages during acute phase and strong influx of macrophages at chronic phase of inflammation. Conclusion and Significance: We introduce 19 F-MRI in combination with PFC nanoemulsions as a new platform to visualize abscess formation in a murine thigh infection model of S. aureus. The possibility to track immune cells in vivo by this modality offers new opportunities to investigate host immune response, the efficacy of antibacterial therapies and th