Political Cycles : Issue Ownership and the Opposition Advantage

We propose a two dimensional infinite horizon model of public consumption in which investments are decided by a winner-take-all election. Investments in the two public goods create a linkage across periods. We follow the idea of issue ownership introduced by Petrocik (1996) in considering parties with different specialties. We show that the incumbent party vote share decreases the longer it stays in power. The median voter is generally not indifferent between the two parties and, when she is moderate enough, no party can maintain itself in power for ever. This result holds when the parties' main objective is to win the election and is compatible with a large range of candidates sub-objectives, that may change from one election to the next. Finally, the more parties are specialized and the more public policies have long-term effects, the more political cycles are likely to occur. ...French Abstract : Nous proposons un modèle de consommation publique à horizon infini. Les investissements engagés dans la fourniture de deux biens publics sont déterminés par les élections. Ces investissements créent un lien entre les élections successives. Nous suivons l'idée introduite par Petrocik (1996) selon laquelle les partis "possèdent" certains thèmes, en considérant qu'ils ont des spécialités différentes. Nous montrons que la part des voix du parti au pouvoir décroît entre deux élections. L'électeur médian n'est généralement pas indifférent entre les deux partis et, lorsqu'il est suffisamment modéré, aucun parti ne peut se maintenir indéfiniment au pouvoir. Ce résultat est valide lorsque l'objectif principal des partis est de gagner l'élection et est compatible avec un grand ensemble de sous objectifs, qui peuvent changer d'une élection à l'autre. Finalement, plus les partis sont spécialisés et plus les politiques ont des effets de long terme, plus les cycles politiques sont susceptibles d'apparaître.CYCLES; ALTERNATION; ISSUE OWNERSHIP; PUBLIC GOODS; OPPOSITION

Limits of flexural wave absorption by open lossy resonators: reflection and transmission problems

The limits of flexural wave absorption by open lossy resonators are analytically and numerically reported in this work for both the reflection and transmission problems. An experimental validation for the reflection problem is presented. The reflection and transmission of flexural waves in 1D resonant thin beams are analyzed by means of the transfer matrix method. The hypotheses, on which the analytical model relies, are validated by experimental results. The open lossy resonator, consisting of a finite length beam thinner than the main beam, presents both energy leakage due to the aperture of the resonators to the main beam and inherent losses due to the viscoelastic damping. Wave absorption is found to be limited by the balance between the energy leakage and the inherent losses of the open lossy resonator. The perfect compensation of these two elements is known as the critical coupling condition and can be easily tuned by the geometry of the resonator. On the one hand, the scattering in the reflection problem is represented by the reflection coefficient. A single symmetry of the resonance is used to obtain the critical coupling condition. Therefore the perfect absorption can be obtained in this case. On the other hand, the transmission problem is represented by two eigenvalues of the scattering matrix, representing the symmetric and anti-symmetric parts of the full scattering problem. In the geometry analyzed in this work, only one kind of symmetry can be critically coupled, and therefore, the maximal absorption in the transmission problem is limited to 0.5. The results shown in this work pave the way to the design of resonators for efficient flexural wave absorption

Aspectos de la corrosión atmosférica de aceros autopasivables

Se estudia la corrosión de aceros Corten y Corcap en un medio que representa una atmósfera urbana industrial. Se compara el comportamiento frente a un acero al carbono corriente. La pasivación de los aceros especiales se logra mediante un ensayo acelerado de inmersiones y emersiones alternadas, la velocidad de corrosión instantánea se mide mediante técnicas electroquímicas de resistencia de polarización. Se discute el efecto que tiene un tratamiento térmico sobre el comportamiento a la corrosión. la capa de pasivaciónse determina mediante espectroscopia infrarroja y Mössbauer

Fast and User-friendly Quantum Key Distribution

Some guidelines for the comparison of different quantum key distribution experiments are proposed. An improved 'plug & play' interferometric system allowing fast key exchange is then introduced. Self-alignment and compensation of birefringence remain. Original electronics implementing the BB84 protocol and allowing user-friendly operation is presented. Key creation with 0.1 photon per pulse at a rate of 486 Hz with a 5.4% QBER - corresponding to a net rate of 210Hz - over a 23 Km installed cable was performed.Comment: 21 pages, 6 figures, added referenc

Price setting in the euro area: Some stylised facts from Individual Producer Price Data

This paper documents producer price setting in 6 countries of the euro area: Germany, France, Italy, Spain, Belgium and Portugal. It collects evidence from available studies on each of those countries and also provides new evidence. These studies use monthly producer price data. The following five stylised facts emerge consistently across countries. First, producer prices change infrequently: each month around 21% of prices change. Second, there is substantial cross-sector heterogeneity in the frequency of price changes: prices change very often in the energy sector, less often in food and intermediate goods and least often in non-durable non- food and durable goods. Third, countries have a similar ranking of industries in terms of frequency of price changes. Fourth, there is no evidence of downward nominal rigidity: price changes are for about 45% decreases and 55% increases. Fifth, price changes are sizeable compared to the inflation rate. The paper also examines the factors driving producer price changes. It finds that costs structure, competition, seasonality, inflation and attractive pricing all play a role in driving producer price changes. In addition producer prices tend to be more flexible than consumer prices.

On two ways to use determinantal point processes for Monte Carlo integration -- Long version

International audienceWhen approximating an integral by a weighted sum of function evaluations, determinantal point processes (DPPs) provide a way to enforce repulsion between the evaluation points. This negative dependence is encoded by a kernel. Fifteen years before the discovery of DPPs, Ermakov & Zolotukhin (EZ, 1960) had the intuition of sampling a DPP and solving a linear system to compute an unbiased Monte Carlo estimator of the integral. In the absence of DPP machinery to derive an efficient sampler and analyze their estimator, the idea of Monte Carlo integration with DPPs was stored in the cellar of numerical integration. Recently, Bardenet & Hardy (BH, 2019) came up with a more natural estimator with a fast central limit theorem (CLT). In this paper, we first take the EZ estimator out of the cellar, and an- alyze it using modern arguments. Second, we provide an efficient implementation1 to sample exactly a particular multidimensional DPP called multivariate Jacobi ensemble. The latter satisfies the assumptions of the aforementioned CLT. Third, our new implementation lets us investigate the behavior of the two unbiased Monte Carlo estimators in yet unexplored regimes. We demonstrate experimentally good properties when the kernel is adapted to basis of functions in which the integrand is sparse or has fast-decaying coefficients. If such a basis and the level of sparsity are known (e.g., we integrate a linear combination of kernel eigenfunctions), the EZ estimator can be the right choice, but otherwise it can display an erratic behavior

On two ways to use determinantal point processes for Monte Carlo integration

International audienceThis paper focuses on Monte Carlo integration with determinantal point processes (DPPs) which enforce negative dependence between quadrature nodes. We survey the properties of two unbiased Monte Carlo estimators of the integral of interest: a direct one proposed by Bardenet & Hardy (2016) and a less obvious 60-year-old estimator by Ermakov & Zolotukhin (1960) that actually also relies on DPPs. We provide an efficient implementation to sample exactly a particular multidimen-sional DPP called multivariate Jacobi ensemble. This let us investigate the behavior of both estima-tors on toy problems in yet unexplored regimes

SABBAC: online Structural Alphabet-based protein BackBone reconstruction from Alpha-Carbon trace

SABBAC is an on-line service devoted to protein backbone reconstruction from alpha-carbon trace. It is based on the assembly of fragments taken from a library of reduced size, selected from the encoding of the protein trace in a hidden Markov model-derived structural alphabet. The assembly of the fragments is achieved by a greedy algorithm, using an energy-based scoring. Alpha-carbon coordinates remain unaffected. SABBAC simply positions the missing backbone atoms, no further refinement is performed. From our tests, SABBAC performs equal or better than other similar on-line approach and is robust to deviations on the alpha-carbon coordinates. It can be accessed at

A model of the CO2 exchanges between biosphere and atmosphere in the tundra

A physical model of the soil thermal regime in a permafrost terrain has been developed and validated with soil temperature measurements at Barrow, Alaska. The model calculates daily soil temperatures as a function of depth and average moisture contents of the organic and mineral layers using a set of five climatic variables, i.e., air temperature, precipitation, cloudiness, wind speed, and relative humidity. The model is not only designed to study the impact of climate change on the soil temperature and moisture regime, but also to provide the input to a decomposition and net primary production model. In this context, it is well known that CO2 exchanges between the terrestrial biosphere and the atmosphere are driven by soil temperature through decomposition of soil organic matter and root respiration. However, in tundra ecosystems, net CO2 exchange is extremely sensitive to soil moisture content; therefore it is necessary to predict variations in soil moisture in order to assess the impact of climate change on carbon fluxes. To this end, the present model includes the representation of the soil moisture response to changes in climatic conditions. The results presented in the foregoing demonstrate that large errors in soil temperature and permafrost depth estimates arise from neglecting the dependence of the soil thermal regime on soil moisture contents. Permafrost terrain is an example of a situation where soil moisture and temperature are particularly interrelated: drainage conditions improve when the depth of the permafrost increases; a decrease in soil moisture content leads to a decrease in the latent heat required for the phase transition so that the heat penetrates faster and deeper, and the maximum depth of thaw increases; and as excepted, soil thermal coefficients increase with moisture