Existence and Nash Implementation of Efficient Sharing Rules for a Commonly Owned Technology

Suppose that a group of individuals owns collectively a technology which produces a consumption good by means of a (possibly heterogeneous) input. A sharing rule associates input contributions with a vector of consumptions that are technologically feasible. We show that the set of allocations obtained by any continuous sharing rule contains a subselection that is Pareto efficient. We also present a mechanism that implements in Nash equilibrium the Pareto efficient allocations contained in an arbitrary sharing rule

Existence and Nash implementation of effcient sharing rules for a commonly owned technology

Suppose that a group of individuals owns collectively a technology which produces a consumption good by means of a (possibly heterogeneous)input. A sharing rule associates input contributions with a vector of consumptions that are technologically feasible. We show that the set of allocations obtained by any continuous sharing rule contains Pareto efficient allocations. We also present a mechanism that implements in Nash equilibrium the Pareto efficient allocations contained in an arbitrary sharing rule.Publicad

Cosmological Recombination of Lithium and its Effect on the Microwave Background Anisotropies

The cosmological recombination history of lithium, produced during Big--Bang nucleosynthesis, is presented using updated chemistry and cosmological parameters consistent with recent cosmic microwave background (CMB) measurements. For the popular set of cosmological parameters, about a fifth of the lithium ions recombine into neutral atoms by a redshift $z\sim 400$. The neutral lithium atoms scatter resonantly the CMB at 6708 \AA and distort its intensity and polarization anisotropies at observed wavelengths around $\sim 300 \mu$m, as originally suggested by Loeb (2001). The modified anistropies resulting from the lithium recombination history are calculated for a variety of cosmological models and found to result primarily in a suppression of the power spectrum amplitude. Significant modification of the power spectrum occurs for models which assume a large primordial abundance of lithium. While detection of the lithium signal might prove difficult, if offers the possibility of inferring the lithium primordial abundance and is the only probe proposed to date of the large-scale structure of the Universe for $z\sim 500-100$.Comment: 20 pages, 7 figure

Chemistry of heavy elements in the Dark Ages

Primordial molecules were formed during the Dark Ages, i.e. the time between recombination and reionization in the early Universe. The purpose of this article is to analyze the formation of primordial molecules based on heavy elements during the Dark Ages, with elemental abundances taken from different nucleosynthesis models. We present calculations of the full non-linear equation set governing the primordial chemistry. We consider the evolution of 45 chemical species and use an implicit multistep method of variable order of precision with an adaptive stepsize control. We find that the most abundant Dark Ages molecules based on heavy elements are CH and OH. Non-standard nucleosynthesis can lead to higher heavy element abundances while still satisfying the observed primordial light abundances. In that case, we show that the abundances of molecular species based on C, N, O and F can be enhanced by two orders of magnitude compared to the standard case, leading to a CH relative abundance higher than that of HD+ or H2D+.Comment: 14 pages, accepted by Astronomy and Astrophysic

Estomatitis aftosa recidivante. 1ª parte: tratamientos locales

La estomatitis aftosa recidivante (EAR) es una enfermedad de la cavidad bucal, de etiología desconocida, común en la población general. Se caracteriza por la aparición de brotes recidivantes de aftas en la mucosa de revestimiento, cuyo síntoma fundamental es el dolor. Esto hace que los pacientes que las padecen precisen de medidas terapéuticas para el control de sus episodios. Por ello, el objetivo de este trabajo es clasificar y resumir los diferentes tipos de tratamientos empleados para el control de la EAR y los resultados obtenidos en los diversos estudios llevados a cabo hasta el momento. Ante la diversidad de medidas terapéuticas propuestas para esta patología, decidimos dividir nuestro trabajo de revisión en dos artículos separados, atendiendo en el primero a la terapia local y en el segundo a los tratamientos sistémicos generalmente recomendados

Non-equilibrium h-2 formation in the early universe: energy exchanges, rate coefficients, and spectral distortions

Energy exchange processes play a crucial role in the early universe, affecting the thermal balance and the dynamical evolution of the primordial gas. In the present work we focus on the consequences of a non-thermal distribution of the level populations of H2: first, we determine the excitation temperatures of vibrational transitions and the non-equilibrium heat transfer; second, we compare the modifications to chemical reaction rate coefficients with respect to the values obtained assuming local thermodynamic equilibrium; and third, we compute the spectral distortions to the cosmic background radiation generated by the formation of H2 in vibrationally excited levels. We conclude that non-equilibrium processes cannot be ignored in cosmological simulations of the evolution of baryons, although their observational signatures remain below current limits of detection. New fits to the equilibrium and non-equilibrium heat transfer functions are provided

Primordial magnetic field and spectral distortion of cosmic background radiation

The role played by a primordial magnetic field during the pre-recombination epoch is analysed through the cyclotron radiation (due to the free electrons) it might produce in the primordial plasma. We discuss the constraint implied by the measurement or lack thereof COBE on this primordial field.Comment: to appear in International Journal of Mod. Phy

Interpretive Authenticity: Performances, Versions, and Ontology

Julian Dodd defends the view that, in musical work-performance practice, interpretive authenticity is a more fundamental value than score compliance authenticity. According to him, compliance with a work’s score can be sacrificed in cases where it conflicts with interpretative authenticity. Stephen Davies and Andrew Kania reject this view, arguing that, if a performer intentionally departs from a work’s score, she is not properly instantiating that work and hence not producing an authentic performance of it. I argue that this objection fails. A detailed analysis of work-performance practice reveals, first, that the normative scope of interpretive authenticity encompasses the practice of composing musical versions and that, second, when performers sacrifice score compliance to maximize interpretive authenticity, they are performing the target work by means of performing a version of it. By means of the nested types theory, I then show how performances produced in this way can be properly formed instances, and hence authentic performances, of their target work.13515

The distribution of two-dimensional eccentricity of Sunyaev-Zeldovich Effect and X-ray surface brightness profiles

With the triaxial density profile of dark matter halos and the corresponding equilibrium gas distribution, we derive two-dimensional Sunyaev-Zeldovich (SZ) effect and X-ray surface brightness profiles for clusters of galaxies. It is found that the contour map of these observables can be well approximated by a series of concentric ellipses with scale-dependent eccentricities. The statistical distribution of their eccentricities (or equivalently axial ratios) is analyzed by taking into account the orientation of clusters with respect to the line of sight and the distribution of the axial ratios and the concentration parameters of dark matter halos. For clusters of mass $10^{13}h^{-1}{M}_{\odot}$ at redshift $z=0$, the axial ratio is peaked at $\eta \sim 0.9$ for both SZ and X-ray profiles. For larger clusters, the deviation from circular distributions is more apparent, with $\eta$ peaked at $\eta \sim 0.85$ for $M=10^{15}h^{-1}{M}_{\odot}$. To be more close to observations, we further study the axial-ratio distribution for mass-limited cluster samples with the number distribution of clusters at different redshifts described by a modified Press-Schechter model. For a mass limit of value $M_{lim}=10^{14}h^{-1}{M}_{\odot}$, the average axial ratio is $\sim 0.84$ with a tail extended to $\eta \sim 0.6$. With fast advance of high quality imaging observations of both SZ effect and X-ray emissions, our analyses provide a useful way to probe cluster halo profiles and therefore to test theoretical halo-formation models.Comment: 28 pages, 6 figures. Accepted for publication in the Astrophysical Journa

Pro-oxidant effect of ALA is implicated in mitochondrial dysfunction of HepG2 cells

Heme biosynthesis begins in the mitochondrion with the formation of delta-aminolevulinic acid (ALA). In acute intermittent porphyria, hereditary tyrosinemia type I and lead poisoning patients, ALA is accumulated in plasma and in organs, especially the liver. These diseases are also associated with neuromuscular dysfunction and increased incidence of hepatocellular carcinoma. Many studies suggest that this damage may originate from ALA-induced oxidative stress following its accumulation. Using the MnSOD as an oxidative stress marker, we showed here that ALA treatment of cultured cells induced ROS production, increasing with ALA concentration. The mitochondrial energetic function of ALA-treated HepG2 cells was further explored. Mitochondrial respiration and ATP content were reduced compared to control cells. For the 300 μM treatment, ALA induced a mitochondrial mass decrease and a mitochondrial network imbalance although neither necrosis nor apoptosis were observed. The up regulation of PGC-1, Tfam and ND5 genes was also found; these genes encode mitochondrial proteins involved in mitochondrial biogenesis activation and OXPHOS function. We propose that ALA may constitute an internal bioenergetic signal, which initiates a coordinated upregulation of respiratory genes, which ultimately drives mitochondrial metabolic adaptation within cells. The addition of an antioxidant, Manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), resulted in improvement of maximal respiratory chain capacity with 300 μM ALA. Our results suggest that mitochondria, an ALA-production site, are more sensitive to pro-oxidant effect of ALA, and may be directly involved in pathophysiology of patients with inherited or acquired porphyria