Bertrand and Walras equilibria under moral hazard

We consider a simple model of competition under moral hazard with constant return technologies. We consider preferences that are not separable in effort: marginal utility of income is assumed to increase with leisure, especially for high income levels. We show that, in this context, Bertrand competition may result in positive equilibrium profit. This result holds for purely idiosyncratic shocks when only deterministic contracts are considered, and extends to unrestricted contract spaces in the presence of aggregate uncertainty. Finally, these findings have important consequences upon the definition of an equilibrium. We show that, in this context, a Walrasian general equilibrium a la Prescott-Townsend may fail to exist: any 'equilibrium' must involve rationing.

Commitment and the Dynamics of Household Labor Supply

The extent to which individuals commit to their partner for life has important implications. This paper develops a lifecycle collective model of the household, through which it characterizes behavior in three prominent alternative types of commitment: full, limited, and no commitment. We propose a test that distinguishes between all three types based on how contemporaneous and historical news affect household behavior. Our test permits heterogeneity in the degree of commitment across households. Using recent data from the Panel Study of Income Dynamics, we reject full and no commitment, while we find strong evidence for limited commitment

Oligomerización dé aldohexosas en DMF-HCl. Estudio del mecanismo

On the basis of the obtained data for acid catalysed oligomerization reactions of D-glucose, D-galactose, D-manose and L-rhamnose in DMFHCl, mechanistic schemes are proposed.Basándose en los datos obtenidos en reacciones de oligomerización catalizadas por ácidos de D-glucosa, D-galactosa, D-manosa y L-rhamnosa en DMF-HGl se proponen esquemas mecanísticos para cada caso

Elimination of Threshold Singularities in the Relation Between On-Shell and Pole Widths

In a previous communication by two of us, Phys. Rev. Lett. 81, 1373 (1998), the gauge-dependent deviations of the on-shell mass and total decay width from their gauge-independent pole counterparts were investigated at leading order for the Higgs boson of the Standard Model. In the case of the widths, the deviation was found to diverge at unphysical thresholds, m_H = 2 root{xi_V} m_V (V = W,Z), in the R_xi gauge. In this Brief Report, we demonstrate that these unphysical threshold singularities are properly eliminated if a recently proposed definition of wave-function renormalization for unstable particles is invoked.Comment: 8 pages (Latex), 1 figure (Postscript

Enhancement-mode PEDOT:PSS organic electrochemical transistors using molecular de-doping

Organic electrochemical transistors (OECTs) show great promise for flexible, low-cost, and low-voltage sensors for aqueous solutions. The majority of OECT devices are made using the polymer blend poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), in which PEDOT is intrinsically doped due to inclusion of PSS. Because of this intrinsic doping, PEDOT:PSS OECTs generally operate in depletion mode, which results in a higher power consumption and limits stability. Here, a straightforward method to de-dope PEDOT:PSS using commercially available amine-based molecular de-dopants to achieve stable enhancement-mode OECTs is presented. The enhancement-mode OECTs show mobilities near that of pristine PEDOT:PSS (≈2 cm2 V−1 s−1) with stable operation over 1000 on/off cycles. The electron and proton exchange among PEDOT, PSS, and the molecular de-dopants are characterized to reveal the underlying chemical mechanism of the threshold voltage shift to negative voltages. Finally, the effect of the de-doping on the microstructure of the spin-cast PEDOT:PSS films is investigated.</p

Expansion for the solutions of the Bogomolny equations on the torus

We show that the solutions of the Bogomolny equations for the Abelian Higgs model on a two-dimensional torus, can be expanded in powers of a quantity epsilon measuring the departure of the area from the critical area. This allows a precise determination of the shape of the solutions for all magnetic fluxes and arbitrary position of the Higgs field zeroes. The expansion is carried out to 51 orders for a couple of representative cases, including the unit flux case. We analyse the behaviour of the expansion in the limit of large areas, in which case the solutions approach those on the plane. Our results suggest convergence all the way up to infinite area.Comment: 26 pages, 8 figures, slightly revised version as published in JHE

N=1/2 gauge theory and its instanton moduli space from open strings in R-R background

We derive the four dimensional N=1/2 super Yang-Mills theory from tree-level computations in RNS open string theory with insertions of closed string Ramond-Ramond vertices. We also study instanton configurations in this gauge theory and their ADHM moduli space, using systems of D3 and D(-1) branes in a R-R background.Comment: 29 pages, 6 figures, JHEP class (included

Las garrapatas de Uruguay : especies, hospedadores, distribución e importancia sanitaria

Se presenta una actualización de las especies de garrapatas de Uruguay. La lista comprende 31 especies que se clasificaron en las siguientes categorías: residentes (15 especies); probablemente residentes (3 especies); accidentales (1 especie); a confirmar (4 especies); diagnóstico erróneo (6 especies) y mención incorrecta (2 especies). Se indica la nueva posición sistemática de algunas especies, así como las sinonimias más relevantes, hospedadoras y distribución de las mismas en el país. Entre las especies de importancia sanitaria, Boophilus microplus continúa siendo la única especie con repercusión en la ganadería de nuestro país, en tanto que, con respecto a la salud humana, se ha detectado que Amblyomma triste es la especie de mayor importancia. Esta es la única especie incriminada en la transmisión de rickettsias al humano en Uruguay. Otras especies como Ornithodoros talaje, Ixodes pararicinus y Rhipicephalus sanguineys se identificaron como vectores potenciales de enfermedades para los animales y los humanos en Uruguay. Factores tales como el ingreso de animales portadores de microorganismos transmisibles por esas especies de garrapatas, cambios ecológicos y climáticos, y la colonización humana de ciertas áreas del país, pueden favorecer que tal riesgo potencial se transforme en real.The Iist of Uruguay tick species is actualized. The 31 Iisted specis were cIassified in the following categories: residents (15 species), probably residents (3) accidentals (1), to confirm (4), erroneous diagnosis (6), and mistaken records (2 species). The new systematic status of some species is clarified, and the more outstanding synonymies, the host and the geographical distribution within Uruguay are indicated. As regards the sanitary impact, Boophilu microplus is still the only species with economic significance to livestock whereas for human health Amblyomma triste is the most important species because is the only one involved with rickettsia's transmission in our country. Several other species, such a Ornithodoros talaje, lxodes pararicinus and Rhipicephalus sanguineus were identified as potential vector of diseases to animal and human. Factor as the introduction of transmissible microorganisms with carrier animals, ecological and climatic change and the human colonization of certain zone of the country, may occasione that this risk becomes a reality.EEA RafaelaFil: Venzal, José Manuel. Universidad de la República. CENUR Litoral Norte-Salto. Facultad de Veterinaria. Departamento de Parasitología; UruguayFil: Castro, Oscar. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Cabrera, P.A. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Souza, C.G. de. Universidad de la República. Facultad de Veterinaria. Departamento de Parasitología Veterinaria; UruguayFil: Guglielmone, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Programmable models of growth and mutation of cancer-cell populations

In this paper we propose a systematic approach to construct mathematical models describing populations of cancer-cells at different stages of disease development. The methodology we propose is based on stochastic Concurrent Constraint Programming, a flexible stochastic modelling language. The methodology is tested on (and partially motivated by) the study of prostate cancer. In particular, we prove how our method is suitable to systematically reconstruct different mathematical models of prostate cancer growth - together with interactions with different kinds of hormone therapy - at different levels of refinement.Comment: In Proceedings CompMod 2011, arXiv:1109.104

N=1/2 quiver gauge theories from open strings with R-R fluxes

We consider a four dimensional N=1 gauge theory with bifundamental matter and a superpotential, defined on stacks of fractional branes. By turning on a flux for the R-R graviphoton field strength and computing open string amplitudes with insertions of R-R closed string vertices, we introduce a non-anticommutative deformation and obtain the N=1/2 version of the theory. We also comment on the appearance of a new structure in the effective Lagrangian.Comment: 30 pages, 5 figures, JHEP class (included); some comments and a reference adde