Certeza Jurídica e Incentivos a la Inversión: Política y Práctica de una Relación Causal

Los autores argumentan que brindar una mayor certeza jurídica a las inversiones, mediante la reducción en los espacios de comportamiento oportunista, tanto del Estado como de otros agentes privados, puede lograrse a través de dos mecanismos: i) la perfección de los marcos regulatorios y de competencia con miras a reducir la aparición de conflictos y de resolverlos en forma expedita y confiable, y, ii) la asignación y protección de derechos de propiedad en mercados con claras deficiencias en su funcionamiento. Para ilustrar esta hipótesis, se sintetizan en este trabajo algunos proyectos de ley discutidos en los últimos cuatro años. Una conclusión que emerge de este trabajo es que efectivamente es posible generar un aumento en las tasas de inversión y mejora en su calidad sin recurrir a subsidios sectoriales, sino que con la implementación de una institucionalidad capaz de mejorar la certeza jurídica a las inversionesCerteza jurídica, Fortalecimiento institucional, Marco regulador

Correlation functions in scalar field theory at large charge

We compute general higher-point functions in the sector of large charge operators ϕn,ϕ¯¯¯n at large charge in O(2) (ϕ¯¯¯ϕ)2 theory. We find that there is a special class of "extremal" correlators having only one insertion of ϕ¯¯¯n that have a remarkably simple form in the double-scaling limit n →∞ at fixed g n2 ≡ λ, where g ~ ϵ is the coupling at the O(2) Wilson-Fisher fixed point in 4 − ϵ dimensions. In this limit, also non-extremal correlators can be computed. As an example, we give the complete formula for ⟨ϕ(x1)nϕ(x2)nϕ¯¯¯(x3)nϕ¯¯¯(x4)n⟩, which reveals an interesting structure

A deep and wide-field view at the IC 2944/2948 complex in Centaurus

We employed the ESO Max Planck Institute (MPI) wide-field camera (Baade et al.) and obtained deep images in the VIC pass-bands in the region of the IC 2944/2948 complex (l ~ 294.°8; b ~ -1.°6), and complemented them with literature and archival data. We used this material to derive the photometric, spectroscopic and kinematic properties of the brightest (V < 16) stars in the region. The VI deep photometry on the other end, helped us to unravel the lower main sequence of a few, possibly physical, star groups in the area. Our analysis confirmed previous suggestions that the extinction towards this line of sight follows the normal law (RV = 3.1). We could recognize B-type stars spread in distance from a few hundred pc to at least 2 kpc. We found two young groups (age ~ 3 Myr) located, respectively, at about 2.3 and 3.2 kpc from the Sun. They are characterized by a significant variable extinction (E(B - V) ranging from 0.28 to 0.45 mag), and host a significant pre-main-sequence population. We computed the initial mass functions for these groups and obtained slopes G{cyrillic} from -0.94 to -1.02 (eG{cyrillic} = 0.3) in a scale where the classical Salpeter law is -1.35. We estimated the total mass of bothmain stellar groups in ~ 1100 and ~ 500M⊙, respectively. Our kinematic analysis indicated that both groups of stars deviate from the standard rotation curve of the Milky Way, in line with literature results for this specific Galactic direction. Finally, along the same line of sight, we identified a third group of early-type stars located at ~8 kpc from the Sun. This group might be located in the far side of the Sagittarius-Carina spiral arm.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Cosmological simulations using a static scalar-tensor theory

We present $\Lambda$CDM $N$-body cosmological simulations in the framework of a static general scalar-tensor theory of gravity. Due to the influence of the non-minimally coupled scalar field, the gravitational potential is modified by a Yukawa type term, yielding a new structure formation dynamics. We present some preliminary results and, in particular, we compute the density and velocity profiles of the most massive group.Comment: 4 pages, 6 figures, to appear in Journal of Physics: Conference Series: VII Mexican School on Gravitation and Mathematical Physics. 26 November to 1 December 2006, Playa del Carmen, Quintana Roo, Mexic

Big data analyses reveal patterns and drivers of the movements of southern elephant seals

The growing number of large databases of animal tracking provides an opportunity for analyses of movement patterns at the scales of populations and even species. We used analytical approaches, developed to cope with big data, that require no a priori assumptions about the behaviour of the target agents, to analyse a pooled tracking dataset of 272 elephant seals (Mirounga leonina) in the Southern Ocean, that was comprised of >500,000 location estimates collected over more than a decade. Our analyses showed that the displacements of these seals were described by a truncated power law distribution across several spatial and temporal scales, with a clear signature of directed movement. This pattern was evident when analysing the aggregated tracks despite a wide diversity of individual trajectories. We also identified marine provinces that described the migratory and foraging habitats of these seals. Our analysis provides evidence for the presence of intrinsic drivers of movement, such as memory, that cannot be detected using common models of movement behaviour. These results highlight the potential for big data techniques to provide new insights into movement behaviour when applied to large datasets of animal tracking.Comment: 18 pages, 5 figures, 6 supplementary figure

Guinea-pig interpubic joint (symphysis pubica) relaxation at parturition: Underlying cellular processes that resemble an inflammatory response

BACKGROUND: At term, cervical ripening in coordination with uterine contractions becomes a prerequisite for a normal vaginal delivery. Currently, cervical ripening is considered to occur independently from uterine contractions. Many evidences suggest that cervical ripening resembles an inflammatory process. Comparatively little attention has been paid to the increased flexibility of the pelvic symphysis that occurs in many species to enable safe delivery. The aim of this study was to investigate whether the guinea-pig interpubic joint relaxation process observed during late pregnancy and parturition resembles an inflammatory process. METHODS: Samples of pubic symphysis were taken from pregnant guinea-pigs sacrificed along gestation, parturition and postpartum. Serial sections of paraffin-embedded tissues were used to measure the interpubic distance on digitalized images, stained with Giemsa to quantify leukocyte infiltration and to describe the vascular area changes, or studied by the picrosirius-polarization method to evaluate collagen remodeling. P4 and E2 serum levels were measured by a sequential immunometric assay. RESULTS: Data showed that the pubic relaxation is associated with an increase in collagen remodeling. In addition, a positive correlation between E2 serum levels and the increase in the interpubic distance was found. On the other hand, a leukocyte infiltration in the interpubic tissue around parturition was described, with the presence of almost all inflammatory cells types. At the same time, histological images show an increase in vascular area (angiogenesis). Eosinophils reached their highest level immediately before parturition; whereas for the neutrophilic and mononuclear infiltration higher values were recorded one day after parturition. Correlation analysis showed that eosinophils and mononuclear cells were positively correlated with E2 levels, but only eosinophilic infiltration was associated with collagen remodeling. Additionally, we observed typical histological images of dissolution of the connective tissue matrix around eosinophils. CONCLUSION: The present study shows that a timely regulated influx of infiltrating leukocytes is associated with an extensive collagen remodeling process that allows the pubic separation for a normal delivery in guinea-pig. Thus, the findings in this study support the hypothesis that the guinea-pig pubic symphyseal relaxation at parturition resembles an inflammatory process