Asset-price boom-bust cycles and credit: what is the scope of macro-prudential regulation?

Over the recent months, several initiatives have taken place to develop macro-prudential regulation in order to prevent systemic risk and the built-up of financial imbalances. Crucial to the success of such policy is the ability of the macro-prudential authority to identify in due time such imbalances, generally featured by asset-price boom-bust cycles. In this paper, we investigate the possibility of detecting asset-price booms according to alternative identification strategies and assess their robustness. We infer the probability that an asset-price boom turns into an asset-price bust. In addition, we try to disentangle costless or low-cost from costly asset-price booms. We find some evidence that house price booms are more likely to turn into costly recession than stock price booms. Resorting both to a non-parametric approach and a discrete-choice (logit) model, we analyze the ability of a set of indicators to robustly explain costly asset-price booms. According to our results, real long-term interest rates, total investment, real credit and real stock prices tend to increase the probability of a costly housing-price boom, whereas real GDP and house prices tend to increase the probability of a costly stock-price boom. Regarding the latter, credit variables tend to play a less convincing role. From this perspective, we specify the scope of macro-prudential regulation as a set of tools aiming at avoiding "costly" asset-price booms. In doing so, we try both to make the case for state-contingent macro-prudential regulations and to set out clear delineation between monetary and financial stability objectives.Early Warning Indicators , Discrete-Choice Model , Asset Price Booms and Busts , Macro-prudential Regulation , Leaning Against the Wind Policies.

Continuous Forest Fire Propagation in a Local Small World Network Model

This paper presents the development of a new continuous forest fire model implemented as a weighted local small-world network approach. This new approach was designed to simulate fire patterns in real, heterogeneous landscapes. The wildland fire spread is simulated on a square lattice in which each cell represents an area of the land's surface. The interaction between burning and non-burning cells, in the present work induced by flame radiation, may be extended well beyond nearest neighbors. It depends on local conditions of topography and vegetation types. An approach based on a solid flame model is used to predict the radiative heat flux from the flame generated by the burning of each site towards its neighbors. The weighting procedure takes into account the self-degradation of the tree and the ignition processes of a combustible cell through time. The model is tested on a field presenting a range of slopes and with data collected from a real wildfire scenario. The critical behavior of the spreading process is investigated

X-ray AGN in the XMM-LSS galaxy clusters: no evidence of AGN suppression

We present a study of the overdensity of X-ray selected AGN in 33 galaxy clusters in the XMM-LSS field, up to redhift z=1.05. Previous studies have shown that the presence of X-ray selected AGN in rich galaxy clusters is suppressed. In the current study we investigate the occurrence of X-ray selected AGN in low and moderate X-ray luminosity galaxy clusters. Due to the wide contiguous XMM-LSS survey area we are able to extend the study to the cluster outskirts. We therefore determine the projected overdensity of X-ray point-like sources out to 6r_{500} radius. To provide robust statistical results we also use a stacking analysis of the cluster projected overdensities. We investigate whether the observed X-ray overdensities are to be expected by estimating also the corresponding optical galaxy overdensities. We find a positive X-ray projected overdensity at the first radial bin, which is however of the same amplitude as that of optical galaxies. Therefore, no suppression of X-ray AGN activity with respect to the field is found, implying that the mechanisms responsible for the suppression are not so effective in lower density environments. After a drop to roughly the background level between 2 and 3r_{500}, the X-ray overdensity exhibits a rise at larger radii, significantly larger than the corresponding optical overdensity. Finally, using redshift information of all optical counterparts, we derive the spatial overdensity profile of the clusters. We find that the agreement between X-ray and optical overdensities in the first radial bin is also suggested in the 3-dimensional analysis. However, we argue that the X-ray overdensity "bump" at larger radial distance is probably a result of flux boosting by gravitational lensing of background QSOs. For high redshift clusters an enhancement of X-ray AGN activity in their outskirts is still possible.Comment: 16 pages. Accepted for publication in A&

Universal shape law of stochastic supercritical bifurcations: Theory and experiments

A universal law for the supercritical bifurcation shape of transverse one-dimensional (1D) systems in presence of additive noise is given. The stochastic Langevin equation of such systems is solved by using a Fokker-Planck equation leading to the expression for the most probable amplitude of the critical mode. From this universal expression, the shape of the bifurcation, its location and its evolution with the noise level are completely defined. Experimental results obtained for a 1D transverse Kerr-like slice subjected to optical feedback are in excellent agreement.Comment: 5 pages, 5 figure

Physical-chemical stability of docetaxel concentrated solution during one month

Background  Docetaxel is an antineoplastic agent widely used in combination with others cytotoxic agents in many cancers (breast cancer, non-small cell lung cancer, prostate cancer, etc.). Today, this costly cytotoxic agent is marketed by several pharmaceutical companies who suggest discarding any remainder immediately after use, making it a very costly drug. Purpose  The aim of this study was to determine the physical-chemical stability of docetaxel stock solution after the first sampling in the vial. Materials and methods  The study was conducted in accordance with European consensus guidelines for the practical stability of anticancer drugs (1) and by two societies GERPAC and SFPC (2). The physical-chemical stability was assessed on 3 different vials of docetaxel (Taxotere 20 mg/mL). On day 0, 2, 4 and 30 triplicate samples of each vial of docetaxel were assayed by a high performance liquid chromatography (HPLC) method with UV detection at 230 nm (method validated following ICH guidelines). Docetaxel concentration at day 0 was considered to be 100% and if the docetaxel concentrations in samples were greater than 90% in the following days they were considered stable. The reference concentration was degraded by 20% by addition of a quantity of 0.01N NaOH in order to produce and observe primary degradation products. On each vial and on different days, docetaxel UV absorption spectra between 200 and 600 nm, pH and colour change were compared by a visual inspection with reference at T = 0, and finally a turbidimetry method at 350, 410 and 530 nm was used to evaluate the formation of visible and sub-visible particles. Results  After 30 days, for each sample, no colour or pH change were observed, all UV spectra and turbidimetry measures were strictly similar. From day 2 to day 30, docetaxel concentrations were not significantly different to the day 0 solution and no degradation products were observed in any samples. According to these results, no significant drug loss was shown during the study period. Conclusions  At a storage temperature between 20 to 25°C for 30 days, docetaxel solution at 20 mg/mL was seen to be stable. The sterility of the solution was not tested because the handling environment (Iso 5) was strictly controlled and operator validations are regularly checked

Dielectric resonances of lattice animals and other fractal structures

Electrical and optical properties of binary inhomogeneous media are currently modelled by a random network of metallic bonds (conductance $\sigma_0$, concentration $p$) and dielectric bonds (conductance $\sigma_1$, concentration $1-p$). The macroscopic conductivity of this model is analytic in the complex plane of the dimensionless ratio $h=\sigma_1/\sigma_0$ of the conductances of both phases, cut along the negative real axis. This cut originates in the accumulation of the resonances of clusters with any size and shape. We demonstrate that the dielectric response of an isolated cluster, or a finite set of clusters, is characterised by a finite spectrum of resonances, occurring at well-defined negative real values of $h$, and we define the cross-section which gives a measure of the strength of each resonance. These resonances show up as narrow peaks with Lorentzian line shapes, e.g. in the weak-dissipation regime of the $RL-C$ model. The resonance frequencies and the corresponding cross-sections only depend on the underlying lattice, on the geometry of the clusters, and on their relative positions. Our approach allows an exact determination of these characteristics. It is applied to several examples of clusters drawn on the square lattice. Scaling laws are derived analytically, and checked numerically, for the resonance spectra of linear clusters, of lattice animals, and of several examples of self-similar fractals.Comment: 25 pages, plain TeX. Figures (hard copies) available upon request, to appear in the Journal of Physics

CHARACTERIZATION OF NEMOTIC DENTAL FIBROBLASTS

Oral Communication presented at the ";Forum des Jeunes Chercheurs";, Brest (France) 2011

Radiant Temperature of Cattle According to Rangeland Environment and Breed

Heat stress can reduce growth rate and reproduction of beef cattle in tropical regions, which might be accentuated under a scenario of climate change. Adaptation of breeds, acclimatisation of individuals, and shade (natural or artificial) can be used to mitigate heat stress in cattle with body temperature used as an indicator (Finch 1977). In the past few years, infrared temperature (IRT) of the eye and hide have been used as an indicators of core body temperature for disease detection and heat produced (Schaefer et al. 2012; Montanholi et al. 2008). IRT could become an automatic and remote measurement of body temperature to monitor environmental and physiological events related to heat stress. Thus, IRT could assist with management decisions concerning shade, water, disease, and animal selection. However, there is no information comparing body temperature of cattle under different rangeland environments (e.g. woodlands vs. savannas). The objective of this study was to determine body temperature of cattle in relation to breed, age and environmental conditions (ambient temperature and shade) using a non-invasive methodology