403 research outputs found

    The Integration of Securitized Real Estate and Financial Assets

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    Empirical evidence suggests that U.S. REITs are integrated with common stocks, but not with bonds. The design of the real estate security is likely to impact upon results, however, and it would seem important to analyze the topic of integration for another type of real estate security. Swiss real estate funds constitute an ideal candidate for such an examination as their institutional and legal setup differs substantially from that of other countries. We analyze the integration of such funds with both the stock and bond markets using an APT framework. We employ both the Xu (2003) method and an innovative procedure to determine endogenous and exogenous factors, respectively. Integration is assessed by means of two alternative tests. Our results suggest that Swiss real estate funds are more integrated with stocks than with bonds. Further, we show that the degree of integration between real estate and stocks is due to a stock market factor and changes in expected inflation. No integrating factor is found between real estate and bond funds. Finally, it is found that unexpected inflation is a segmenting factor between real estate securities and financial assets.Securitized Real Estate; Statistical APT; Macroeconomic APT; Market Integration; Risk Factors

    Full embeddings of (α,β)-geometries in projective spaces—Part II

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    AbstractThe incidence structures known as (α,β)-geometries are a generalization of partial geometries and semipartial geometries. In a previous paper, a classification of (α,β)-geometries fully embedded in PG(n,q), q odd and α>1, assuming that every plane of PG(n,q) containing an antiflag of S is either an α-plane or a β-plane, is given. The case that there is a so-called mixed plane and that β=q+1, is also treated there. In this paper we will treat the case β=q. This completes the classification of all proper (α,β)-geometries fully embedded in PG(n,q), q odd and α>1, such that PG(n,q) contains at least one α- or one β-plane. For q even, some partial results are obtained

    Seismic Noise by Wind Farms: A Case Study from the Virgo Gravitational Wave Observatory, Italy

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    We present analyses of the noise wave field in the vicinity of Virgo, the Italian–French gravitational wave observatory located close to Pisa, Italy, with special reference to the vibrations induced by a nearby wind farm. The spectral contribution of the wind turbines is investigated using (1) onsite measurements, (2) correlation of spectral amplitudes with wind speed, (3) directional properties determined via multichannel measurements, and (4) attenuation of signal amplitude with distance. Among the different spectral peaks thus discriminated, the one at frequency 1.7 Hz is associated with the greatest power, and under particular conditions it can be observed at distances as large as 11 km from the wind farm. The spatial decay of amplitudes exhibits a complicated pattern, which we interpret in terms of the combination of direct surface waves and body waves refracted at a deep (≈800 m) interface between the Plio-Pleistocenic marine, fluvial, and lacustrine sediments and the Miocene carbonate basement. We develop a model for wave attenuation that allows determining the amplitude of the radiation from individual turbines, which is estimated on the order of 300–400 μms_1/ √Hz for wind speeds over the 8–14 m=s range. On the basis of this model, we then develop a predictive relationship for assessing the possible impact of future wind farm projects

    A Code-Based Group Signature Scheme

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    International audienceIn this work we propose the first code-based group signature. As it will be described below, its security is based on a relaxation of the model of Bel-lare, Shi and Zhang [3] (BSZ model) verifying the properties of anonymity, traceability and non-frameability. Furthermore, it has numerous advantages over all existing post-quantum constructions and even competes (in terms of properties) with pairing based constructions: it allows to dynamically add new members and signature and public key sizes are constant with respect to the number of group members. Last but not least, our scheme can be extended into a traceable signature according to the definition of Kiayias, Tsiounis and Yung [19] (KTY model) and handles membership revocation. The main idea of our scheme consists in building a collision of two syndromes associated to two different matrices: a random one which enables to build a random syndrome from a chosen small weight vector; and a trapdoor matrix for the syndrome decoding problem, which permits to find a small weight preimage of the previous random syndrome. These two small weight vectors will constitute the group member's secret signing key whose knowledge will be proved thanks to a variation of Stern's authentication protocol. For applications , we consider the case of the code-based CFS signature scheme [11] of Courtois, Finiasz and Sendrier

    Seismic Noise by Wind Farms: A Case Study from the VIRGO Gravitational Wave Observatory, Italy.

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    We present analyses of the noise wavefield in the vicinity of VIRGO, the Italy-France gravitational wave observatory located close to Pisa, Italy, with special reference to the vibrations induced by a nearby wind park. The spectral contribution of the wind turbines is investigated using (i) on-site measurements, (ii) correlation of spectral amplitudes with wind speed, (iii) directional properties determined via multichannel measurements, and (iv) attenuation of signal amplitude with distance. Among the different spectral peaks thus discriminated, the one at frequency 1.7 Hz has associated the greatest power, and under particular conditions it can be observed at distances as large as 11 km from the wind park. The spatial decay of amplitudes exhibits a complicate pattern, that we interpret in terms of the combination of direct surface waves and body waves refracted at a deep (_ 800 m) interface between the plio-pleistocenic marine, fluvial and lacustrine sediments and the Miocene carbonate basement. We develop a model for wave attenuation which allows determining the amplitude of the radiation from individual turbines, which is estimated on the order of 300-400 μms−119 /pHz for wind speeds over the 8-14 m/s range. On the base of this model, we then develop a predictive relationship for assessing the possible impact of future, project wind farms

    Bacteriophages pass through candle-shaped porous ceramic filters: Application for the collection of viruses in soil water

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    Despite the ubiquity of viruses in soils, their diversity in soil water has not been explored, mainly due to the difficulty of collecting them. In hydrology, soil water is usually collected using porous candles. This study proposes using these porous candles as a new tool for sampling viruses in soil water to analyze their passage through the ceramic part of the candles. The recovery of the viruses was determined after filtration under laboratory conditions using three model bacteriophages (MS2, ΦX174, and Φ6) and Escherichia coli, at neutral and acidic pH. Then, a field experiment was carried out where soil water filtration and viral identification by metagenomic shotgun were performed. At neutral pH, all bacteriophages tested successfully passed through the porous candles during the filtration process, with reductions of 0.02 log, 0.16 log, and 0.55 log for MS2 ΦX174 and Φ6, respectively. At pH 4.4, the passage of MS2 was not affected while ΦX174 underwent a slight reduction in recovery, probably caused by adsorption onto the filter material. Regarding the application of the porous candles in the field, the results obtained allowed the successful recovery of viruses, exposing porous candles as a new method suitable for the collection of viruses from soil water in the context of the study of viral communities
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