Properties of codimension-2 braneworlds in six-dimensional Lovelock theory

We consider maximally symmetric 3-branes embedded in a six-dimensional bulk spacetime with Lovelock dynamics. We study the properties of the solutions with respect to their induced curvature, their vacuum energy and their effective compactness in the extra dimensions. Some simple solutions are shown to give rise to self-accelerating braneworlds, whereas several others solutions have self-tuning properties. For the case of geometric self-acceleration we argue that the cross-over scale in between four-dimensional and higher-dimensional gravity and the scale of late-time geometric acceleration, fixed by the present horizon size, are related via the conical deficit angle of the six-dimensional bulk solution, which is a free parameter.Comment: 6 pages, prepared for the 13th Conference on Recent Developments in Gravity (NEB XIII), Thessaloniki, Greece, 4 - 6 Jun 2008; v2: reference adde

Properties of codimension-2 braneworlds in six-dimensional Lovelock theory

We consider maximally symmetric 3-branes embedded in a six-dimensional bulk spacetime with Lovelock dynamics. We study the properties of the solutions with respect to their induced curvature, their vacuum energy and their effective compactness in the extra dimensions. Some simple solutions are shown to give rise to self-accelerating braneworlds, whereas several others solutions have self-tuning properties. For the case of geometric self-acceleration we argue that the cross-over scale in between four-dimensional and higher-dimensional gravity and the scale of late-time geometric acceleration, fixed by the present horizon size, are related via the conical deficit angle of the six-dimensional bulk solution, which is a free parameter.Comment: 6 pages, prepared for the 13th Conference on Recent Developments in Gravity (NEB XIII), Thessaloniki, Greece, 4 - 6 Jun 2008; v2: reference adde

Properties of codimension-2 braneworlds in six-dimensional Lovelock theory

We consider maximally symmetric 3-branes embedded in a six-dimensional bulk spacetime with Lovelock dynamics. We study the properties of the solutions with respect to their induced curvature, their vacuum energy and their effective compactness in the extra dimensions. Some simple solutions are shown to give rise to self-accelerating braneworlds, whereas several others solutions have self-tuning properties. For the case of geometric self-acceleration we argue that the cross-over scale in between four-dimensional and higher-dimensional gravity and the scale of late-time geometric acceleration, fixed by the present horizon size, are related via the conical deficit angle of the six-dimensional bulk solution, which is a free parameter.Comment: 6 pages, prepared for the 13th Conference on Recent Developments in Gravity (NEB XIII), Thessaloniki, Greece, 4 - 6 Jun 2008; v2: reference adde

The consistency of codimension-2 braneworlds and their cosmology

We study axially symmetric codimension-2 cosmology for a distributional braneworld fueled by a localised 4D perfect fluid, in a 6D Lovelock theory. We argue that only the matching conditions (dubbed topological) where the extrinsic curvature on the brane has no jump describe a pure codimension-2 brane. If there is discontinuity in the extrinsic curvature on the brane, this induces inevitably codimension-1 distributional terms. We study these topological matching conditions, together with constraints from the bulk equations evaluated at the brane position, for two cases of regularisation of the codimension-2 defect. First, for an arbitrary smooth regularisation of the defect and second for a ring regularisation which has a cusp in the angular part of the metric. For a cosmological ansatz, we see that in the first case the coupled system is not closed and requires input from the bulk equations away from the brane. The relevant bulk function, which is a time-dependent angular deficit, describes the energy exchange between the brane and the 6D bulk. On the other hand, for the ring regularisation case, the system is closed and there is no leakage of energy in the bulk. We demonstrate that the full set of matching conditions and field equations evaluated at the brane position are consistent, correcting some previous claim in the literature which used rather restrictive assumptions for the form of geometrical quantities close to the codimension-2 brane. We analyse the modified Friedmann equation and we see that there are certain corrections coming from the non-zero extrinsic curvature on the brane. We establish the presence of geometric self-acceleration and a possible curvature domination wedged in between the period of matter and self-acceleration eras as signatures of codimension-2 cosmology.Comment: 21 pages, 5 figures, journal versio

The Dynamic Adjustment of a Transition Economy in the Early Stages of Transformation

This paper develops a model of a representative transition economy to explain the stylised facts of output declines and real exchange rate appreciation in the early stages of transformation. These facts can be explained by supply-side shocks, interest rate liberalisation or a reduction in core inflation. The policy implication is that price liberalisation in advance of financial liberalization and structural reform, including widespread privatisation of the production process, necessarily results in some temporary loss of output.Transition dynamics, overshooting, competitiveness, output decline

The determinants of current account imbalances in the Euro Area: a panel estimation approach

The purpose of this paper is to explore the main macroeconomic, financial and structural factors that influenced current account developments in the euro area countries over the period from 1980 to 2008. The analysis, which theoretically rests on the intertemporal approach, uses a panel consisting of the twelve EU member states that initially joined the euro area, which is then expanded to seventeen countries with the aim to see whether the enlargement or potential enlargement of the euro area would alter the identified set of current account determinants. The results show that factors such as the level of development, demographics, macroeconomic policies and competitiveness, are important in explaining current account positions of individual euro area countries. Moreover, the analysis of short-run dynamics indicates that the EMU has resulted in longer periods of adjustment of current account imbalances.Current account determinants; euro area imbalances

Current account determinants and external sustainability in periods of structural change

The aim of this paper is to study the main macroeconomic, financial and structural characteristics that affected current account developments in Greece over the period 1960-2007 and link these to the issue of external sustainability. Concerns over Greece’s external sustainability have emerged since 1999 when the current account deficit widened substantially and exhibited high persistence. The empirical model used, which theoretically rests on the intertemporal approach, treats the current account as the gap between domestic saving and investment. We examine the behaviour of the current account in the long run and the short run using co-integration analysis and a variety of econometric tests to account for the effect of significant structural changes in the period under review. We find that a stable equilibrium current account model can be derived if the ratio of private sector financing to GDP, as a proxy for financial liberalization, is included in the specification. Policy options to restore the country’s external sustainability are explored by performing a simulation exercise based on the estimated equilibrium model.Current account model; external sustainability

Current account determinants and external sustainability in periods of structural change

The aim of this paper is to study the main macroeconomic, financial and structural factors that shaped current account developments in Greece over the period from 1960 to 2007 and discuss these developments in relation to the issue of external sustainability. Concerns over Greece’s external sustainability have emerged since 1999 when the current account deficit widened substantially and exhibited high persistence. The empirical model used, which theoretically rests on the intertemporal approach, treats the current account as the gap between domestic saving and investment. We examine the behaviour of the current account in the long run and the short run using co-integration analysis and a variety of econometric tests to account for the effect of significant structural changes in the period under review. We find that a stable equilibrium current account model can be derived if the ratio of private sector financing to GDP, as a proxy for financial liberalisation, is included in the specification. Policy options to restore the country’s external sustainability are explored based on the estimated equilibrium model. JEL Classification: F30, F32Current account model, external sustainability

In the Footsteps of Scribonius Largus, a Pioneer of Clinical Pharmacy in Ancient Rome

Clinical pharmacy involves pharmacists in direct patient care concerning optimizing medicines and promoting health awareness and disease prevention. The whereabouts of the field can be traced to Scribonius Largus, a renowned physician and pharmacist in ancient Rome. Although Largus served as an imperial physician, he has also been an exemplary pharmacist authoring a comprehensive pharmacognosy textbook and dedicated a big part of his life to improving pharmacotherapy and advancing ethics in the field. Revisiting his contributions provides valuable lessons for contemporary clinical pharmacists