Global Asset Return in Pension Funds: a dynamical risk analysis

The aim of the paper is to develop a technique for rebalancing pension fund portfolios in function of their pointwise level of risk. The performance of pension funds is often measured by their global asset returns because of the latter’s influence on periodic contributions and/or future benefits. However, in periods of market crisis attention is focused on the risk level given their social security (and not speculative) function. We describe the process of the global asset return by a multifractional Brownian motion using the function H(t) to detect high or low volatility phases. A procedure is carried out to balance the asset composition when the established local degree of risk is exceeded. The application is carried out on portfolios obtained in accordance with Italian regulations regarding investment limits.Pension Funds, risk control, multifractional Brownian motion

Extreme UV QSOs

We present a sample of spectroscopically confirmed QSOs with FUV-NUV color (as measured by GALEX photometry) bluer than canonical QSO templates and than the majority of known QSOs. We analyze their FUV to NIR colors, luminosities and optical spectra. The sample includes a group of 150 objects at low redshift (z $<$ 0.5), and a group of 21 objects with redshift 1.7$<$z$<$2.6. For the low redshift objects, the "blue" FUV-NUV color may be caused by enhanced Ly$\alpha$ emission, since Ly$\alpha$ transits the GALEX FUV band from z=0.1 to z=0.47. Synthetic QSO templates constructed with Ly$\alpha$ up to 3 times stronger than in standard templates match the observed UV colors of our low redshift sample. The H$\alpha$ emission increases, and the optical spectra become bluer, with increasing absolute UV luminosity. The UV-blue QSOs at redshift about 2, where the GALEX bands sample restframe about 450-590A (FUV) and about 590-940A(NUV), are fainter than the average of UV-normal QSOs at similar redshift in NUV, while they have comparable luminosities in other bands. Therefore we speculate that their observed FUV-NUV color may be explained by a combination of steep flux rise towards short wavelengths and dust absorption below the Lyman limit, such as from small grains or crystalline carbon. The ratio of Ly$\alpha$ to CIV could be measured in 10 objects; it is higher (30% on average) than for UV-normal QSOs, and close to the value expected for shock or collisional ionization. FULL VERSION AVAILABLE FROM AUTHOR'S WEB SITE: http://dolomiti.pha.jhu.edu/papers/2009_AJ_Extreme_UV_QSOs.pdfComment: Astronomical Journal, in pres

Tel1ATM dictates the replication timing of short yeast telomeres

Telomerase action is temporally linked to DNA replication. Although yeast telomeres are normally late replicating, telomere shortening leads to early firing of subtelomeric DNA replication origins. We show that double‐strand breaks flanked by short telomeric arrays cause origin firing early in S phase at late‐replicating loci and that this effect on origin firing time is dependent on the Tel1ATM checkpoint kinase. The effect of Tel1ATM on telomere replication timing extends to endogenous telomeres and is stronger than that elicited by Rif1 loss. These results establish that Tel1ATM specifies not only the extent but also the timing of telomerase recruitment

Increased association of telomerase with short telomeres in yeast

Telomere function is mediated by the assembly of a protein complex on an array of telomeric DNA (TG) repeats synthesized by the telomerase enzyme. Telomerase action at chromosome ends is finely tuned by the telomeric complex so that a constant average number of repeats is maintained. This is achieved through a negative feedback process that is sensitive to TG tract length, but whose underlying mechanism is unknown. We show that short telomeres, which are preferential substrates for telomerase, display increased association with the enzyme in the S phase of the cell cycle, when telomerase acts. In addition, we provide support for a molecular mechanism by which this key step of telomerase recruitment is regulated by TG tract length

TTP-free Asymmetric Fingerprinting based on Client Side Embedding

In this paper, we propose a solution for implementing an asymmetric fingerprinting protocol within a client-side embedding distribution framework. The scheme is based on two novel client-side embedding techniques that are able to reliably transmit a binary fingerprint. The first one relies on standard spread-spectrum like client-side embedding, while the second one is based on an innovative client-side informed embedding technique. The proposed techniques enable secure distribution of personalized decryption keys containing the Buyer's fingerprint by means of existing asymmetric protocols, without using a trusted third party. Simulation results show that the fingerprint can be reliably recovered by using either non-blind decoding with standard embedding or blind decoding with informed embedding, and in both cases it is robust with respect to common attacks. To the best of our knowledge, the proposed scheme is the first solution addressing asymmetric fingerprinting within a clientside framework, representing a valid solution to both customer's rights and scalability issues in multimedia content distributio

Secure Watermarking for Multimedia Content Protection: A Review of its Benefits and Open Issues

Distribution channels such as digital music downloads, video-on-demand, multimedia social networks, pose new challenges to the design of content protection measures aimed at preventing copyright violations. Digital watermarking has been proposed as a possible brick of such protection systems, providing a means to embed a unique code, as a fingerprint, into each copy of the distributed content. However, application of watermarking for multimedia content protection in realistic scenarios poses several security issues. Secure signal processing, by which name we indicate a set of techniques able to process sensitive signals that have been obfuscated either by encryption or by other privacy-preserving primitives, may offer valuable solutions to the aforementioned issues. More specifically, the adoption of efficient methods for watermark embedding or detection on data that have been secured in some way, which we name in short secure watermarking, provides an elegant way to solve the security concerns of fingerprinting applications. The aim of this contribution is to illustrate recent results regarding secure watermarking to the signal processing community, highlighting both benefits and still open issues. Some of the most interesting challenges in this area, as well as new research directions, will also be discussed

China's Emergence in the World Economy and Business Cycles in Latin America

The international business cycle is very important for Latin America’s economic performance as the recent global crisis vividly illustrated. This paper investigates how changes in trade linkages between China, Latin America, and the rest of the world have altered the transmission mechanism of international business cycles to Latin America. Evidence based on a Global Vector Autoregressive (GVAR) model for 5 large Latin American economies and all major advanced and emerging economies of the world shows that the long-term impact of a China GDP shock on the typical Latin American economy has increased by three times since mid-1990s. At the same time, the long-term impact of a US GDP shock has halved, while the transmission of shocks to Latin America and the rest of emerging Asia (excluding China and India) GDP has not undergone any significant change. Contrary to common wisdom, we find that these changes owe more to the changed impact of China on Latin America’s traditional and largest trading partners than to increased direct bilateral trade linkages boosted by the decade long commodity price boom. These findings help to explain why Latin America did so well during the global crisis, but point to the risks associated with a deceleration in China’s economic growth in the future for both Latin America and the rest of the world economy. The evidence reported also suggests that the emergence of China as an important source of world growth might be the driver of the so called “decoupling” of emerging markets business cycle from that of advanced economies reported in the existing literature.international business cycle, emerging markets, Great Recession, GVAR, China, Latin America, trade linkages

Design and characterization of a fabric-based softness display

To enable a realistic tactile interaction with remote or virtual objects, softness information represents a fundamental property to be rendered via haptic devices. What is challenging is to reduce the complexity of such an information as it arises from contact mechanics and to find suitable simplifications that can lead an effective development of softness displays. A possible approach is to surrogate detailed tactile cues with information on the rate of spread of the contact area between the object and the finger as the contact force increases, i.e. force/area relation. This paradigm is called contact area spread rate. In this paper we discuss how such a paradigm has inspired the design of a tactile device (hereinafter referred to as Fabric Yielding Display, FYD-2), which exploits the elasticity of a fabric to mimic different levels of stiffness, while the contact area on the finger indenting the fabric is measured. In this manner, the FYD-2 can be controlled to reproduce force-area characteristics. In this work, we describe the FYD-2 architecture and report a psychophysical characterization. FYD-2 is shown to be able to accurately reproduce force-area curves of typical objects and to enable a reliable softness discrimination in human users

Holographic three-point functions: one step beyond the tradition

Within the program of holographic renormalization, we discuss the computation of three-point correlation functions along RG flows. We illustrate the procedure in two simple cases. In an RG flow to the Coulomb branch of N=4 SYM theory we derive a compact and finite expression for the three-point function of lowest CPO's dual to inert scalars. In the GPPZ flow, that captures some features of N=1 SYM theory, we compute the three-point function with insertion of two inert scalars and one active scalar that mixes with the stress tensor. By amputating the external legs at the mass poles we extract the trilinear coupling of the corresponding superglueballs. Finally we outline the procedure for computing three-point functions with insertions of the stress tensor as well as of (broken) R-symmetry currents.Comment: 30 page