A construction of 2-cofiltered bilimits of topoi

We show the existence of bilimits of 2-cofiltered diagrams of topoi, generalizing the construction of cofiltered bilimits developed in "SGA 4 Springer LNM 270 (1972)". For any given such diagram, we show that it can be represented by a 2-cofiltered diagram of small sites with finite limits, and we construct a small site for the inverse limit topos. This is done by taking the 2-filtered bicolimit of the underlying categories and inverse image functors. We use the construction of this bicolimit developed in "A construction of 2-filtered bicolimits of categories, Cah. Top. et Geo. Diff. Vol. XLVII-2 (2006)", where it is proved that if the categories in the diagram have finite limits and the transition functors are exact, then the bicolimit category has finite limits and the pseudocone functors are exact. An application of our result here is the fact that every Galois topos has points "2-Filteredness and the point of every Galois topos, Proc. CT2007, App. Cat. St., Vol. 18, 2, (2010)".Comment: 7 page

Affine Volterra processes

We introduce affine Volterra processes, defined as solutions of certain stochastic convolution equations with affine coefficients. Classical affine diffusions constitute a special case, but affine Volterra processes are neither semimartingales, nor Markov processes in general. We provide explicit exponential-affine representations of the Fourier-Laplace functional in terms of the solution of an associated system of deterministic integral equations of convolution type, extending well-known formulas for classical affine diffusions. For specific state spaces, we prove existence, uniqueness, and invariance properties of solutions of the corresponding stochastic convolution equations. Our arguments avoid infinite-dimensional stochastic analysis as well as stochastic integration with respect to non-semimartingales, relying instead on tools from the theory of finite-dimensional deterministic convolution equations. Our findings generalize and clarify recent results in the literature on rough volatility models in finance

FSR1767 - a new globular cluster in the Galaxy

The globular cluster (GC) nature of the recently catalogued candidate FSR 1767 is established in the present work. It results as the closest GC so far detected in the Galaxy. The nature of this object is investigated by means of 2MASS colour-magnitude diagrams (CMDs), the stellar radial density profile (RDP) and proper-motions (PM). The properties are consistent with an intermediate metallicity (\feh\approx-1.2) GC with a well-defined turnoff (TO), red-giant branch (RGB) and blue horizontal-branch (HB). The distance of FSR 1767 from the Sun is \ds\approx1.5 kpc, and it is located at the Galactocentric distance \rgc\approx5.7 kpc. With the space velocity components $(V,W)=(184\pm14,-43\pm14)\rm km s^{-1}$, FSR 1767 appears to be a Palomar-like GC with \mv\approx-4.7, that currently lies $\approx57$ pc below the Galactic plane. The RDP is well represented by a King profile with the core and tidal radii \rc=0.24\pm0.08 pc and \rt=3.1\pm1.0 pc, respectively, with a small half-light radius \rh=0.60\pm0.15 pc. The optical absorption is moderate for an infrared GC, $A_V=6.2\pm0.3$, which together with its central direction and enhanced contamination explains why it has so far been overlooked.Comment: 6 pages, 7 figures. MNRAS Letters, accepte

The impact of policy announcements and news on capital markets : crisis management in Argentina during the Tequila Effect

Argentina was hit hard by the Mexican crisis of 1994-95. The Argentine peso came under attack and there was a run on bank deposits. Argentina'successfully announced a series of policies to mitigate the spillover effects, without abandoning its currency board. The authors show how capital markets reacted to each policy announcement and piece of breaking news. They find that Argentina's agreement with the International Monetary Fund, the dollarization of reserve deposits in the central bank, and the reduction in reserve requirements, among other things, had a strong positive impact on market returns. The market welcomed announcements that reflected the adoption of credible policies and demonstrated a firm commitment to the currency board. The authors also find that, after a period of higher volatility, the appointment of a new finance minister (after Domingo Cavallo left the finance ministry) calmed down stock and bond markets, significantly decreasing the variance in stock and bond market returns. On the other hand, the interest rate became more volatile after the appointment of the new finance minister and when reserve requirements were lowered.Economic Theory&Research,Banks&Banking Reform,Financial Intermediation,Environmental Economics&Policies,Financial Economics

Verifying exchange rate regimes

Credibility and transparency are at the core of the current debate about exchange rate regimes. The steady growth in the magnitude and variability of international capital flows has complicated the question of whether to use floating, fixed, or intermediate exchange rate regimes. Emerging market economies are abandoning basket pegs, crawling pegs, bands, adjustable pegs, and various combinations of these. One of several reasons intermediate regimes have fallen out of favor is that they are not transparent; it is very difficult to verify them. Verifiability is a concrete example of the principle of"transparency"so often invoked in discussions of the new international financial architecture but so seldom made precise. A simple peg or a simple float may be easier for market participants to verify than a more complicated intermediate regime. The authors investigate how difficult it is for investors to verify from observable data whether the authorities are in fact following the exchange rate regime they claim to be following. Of the various intermediate regimes, they focus on basket pegs with bands. Statistically, it can take a surprisingly long span of data for an econometrician or investor to verify whether such a regime is actually in operation. The authors find that verification becomes more difficult as the regime's bands widen or more currencies enter the basket peg. At the other extreme, they also analyze regimes described as the regime's bands widen or more currencies enter the basket peg. At the other extreme, they also analyze regimes described as free floating and find that in some cases the observed exchange rate data do validate the announced regime.Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Fiscal&Monetary Policy,ICT Policy and Strategies,Fiscal&Monetary Policy,Economic Theory&Research,ICT Policy and Strategies,Economic Stabilization,Macroeconomic Management

Hallazgo de Systrophia argentina n. comb. en la Precordillera argentina, a 150 años de su descripción (Mollusca: Gastropoda: Scolodontoidea)

. Systrophia argentina (Strobel, 1874) n. comb. es redescripta después de 150 años de su descubrimiento. Los ejemplares fueron encontrados en la Precordillera argentina (Quebrada San Isidro, provincia de Mendoza, Argentina), a 2.000 metros sobre el nivel del mar, cerca de su localidad típica. Ésta, aquí es restringida a Villa Vicencio y Casa de Piedra. Presenta una concha de tamaño mediano, planispiral, con 6 vueltas; rádula con placa central tricúspide, y dientes latero-marginales aculeados, fórmula: 13 – C – 13; vagina corta, ducto espermático alcanzando el extreme distal de la vagina, cerca del atrio; bolsa del pene larga, el pene ocupa la mayor parte de la bolsa peniana, epiphallus presenta un músculo retractor en su extremo; glándula cuadrangular grande adherida a la bolsa del pene; atrio muy corto. S. argentina es la única especie del género encontrada hasta el momento en la Argentina, siendo la distribución más austral de Systrophia L. Pfeiffer, 1855.Systrophia argentina (Strobel, 1874) n. comb. is here re-described 150 years after its discovery. The specimens were found in the Argentine Precordillera (Quebrada San Isidro, Mendoza province, Argentina), at 2.000 m, near the typical locality of the species, here restricted to the Angostura or garganta (gullet) of Villa Vicencio and Casa de Piedra. It is the southernmost distribution of the genus. This snail has a shell of medium size, planispiral, with six whorls; radula with central plate tricuspid, and latero-marginal teeth aculeate, formula: 13 – C – 13; vagina short, spermathecal duct reaching the distal extreme of the vagina, near the atrium; penial sheath long, penis occupying most of the penial sheath, epiphallus with a retractor muscle adhered to its extreme, large and quadrangular gland attached to the penial sheath; atrium very short. S. argentina is the only species of Systrophia L. Pfeiffer, 1855 in Argentina, being the most austral distribution of the genus.Fil: Miquel, Sergio Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin