Some unpleasant arithmetics of regional unemployment in the EU. Are there any lessons for EMU?

Several studies have documented the weak response of regional wage differentials and labour mobility following region-specific (“idiosyncraticâ€) shocks in the average of the EU countries. This has been often taken as evidence of the rigidity of labour markets in European countries, as opposed to the flexibility of the USA. However, as such shocks by definition average to zero, one cannot make an explicit link between the (lack of) adjustment at regional level and aggregate unemployment. Moreover, the emphasis on the reaction to short-run idiosyncratic shocks is unlikely to explain the permanent differentials across regions, which characterise the regional distribution of unemployment in many EU countries. This paper tries to provide a better understanding of the regional distribution of unemployment and why region-specific shocks can matter for aggregate unemployment. It does so by explicitly considering the possibility of asymmetric reactions, so that unemployment rises more in poorer areas suffering an adverse shock than it declines in richer regions experiencing a favourable shock. The reason behind such asymmetries is the presence of a wage floor in the poorer regions resulting from policy centralisation, as for instance in the case of a national unemployment compensation system, which provides benefits that are uniform across regions. If such a mechanism is at work, aggregate unemployment tends to be “inflated†by region-specific shocks that are inequality- increasing. After presenting an illustrative model of the mechanism, the paper proposes a simple measure of the resulting “excess unemploymentâ€, based on the difference between the average (national) unemployment rate and the unemployment rate of the median region. It also examines the relationship between regional asymmetries in unemployment and the dispersion of productivity across regions, taken as proxy of the inequality-increasing shocks. The evidence, while not entirely conclusive, justifies two tentative policy conclusions, which are particularly relevant in the context of EMU: a) to avoid centralisation of labour market institutions at the EU level that may end up inflating aggregate unemployment; b) to effectively deploy regional policies to combat inequality- increasing shocks.regional policy, unemployment, disparities

Reaching the millennium development goal for child mortality : improving equity and efficiency in Ecuador's health budget

health care; infant mortality; health policy;

The inner structure and kinematics of the Sagittarius dwarf galaxy as a product of tidal stirring

The tidal stirring model envisions the formation of dwarf spheroidal (dSph) galaxies in the Local Group via the tidal interaction of disky dwarf systems with a larger host galaxy like the Milky Way. These progenitor disks are embedded in extended dark halos and during the evolution both components suffer strong mass loss. In addition, the disks undergo the morphological transformation into spheroids and the transition from ordered to random motion of their stars. Using collisionless N-body simulations we construct a model for the nearby and highly elongated Sagittarius (Sgr) dSph galaxy within the framework of the tidal stirring scenario. Constrained by the present known orbit of the dwarf, the model suggests that in order to produce the majority of tidal debris observed as the Sgr stream, but not yet transform the core of the dwarf into a spherical shape, Sgr must have just passed the second pericenter of its current orbit around the Milky Way. In the model, the stellar component of Sgr is still very elongated after the second pericenter and morphologically intermediate between the strong bar formed at the first pericenter and the almost spherical shape existing after the third pericenter. This is thus the first model of the evolution of the Sgr dwarf that accounts for its observed very elliptical shape. At the present time there is very little intrinsic rotation left and the velocity gradient detected along the major axis is almost entirely of tidal origin. We model the recently measured velocity dispersion profile for Sgr assuming that mass traces light and estimate its current total mass within 5 kpc to be 5.2 x 10^8 M_sun. To have this mass at present, the model requires that the initial virial mass of Sgr must have been as high as 1.6 x 10^10 M_sun, comparable to that of the Large Magellanic Cloud, which may serve as a suitable analog for the pre-interaction, Sgr progenitor.Comment: 14 pages, 14 figures, minor changes to match the version published in Ap

Exosomes regulate neurogenesis and circuit assembly.

Exosomes are thought to be released by all cells in the body and to be involved in intercellular communication. We tested whether neural exosomes can regulate the development of neural circuits. We show that exosome treatment increases proliferation in developing neural cultures and in vivo in dentate gyrus of P4 mouse brain. We compared the protein cargo and signaling bioactivity of exosomes released by hiPSC-derived neural cultures lacking MECP2, a model of the neurodevelopmental disorder Rett syndrome, with exosomes released by isogenic rescue control neural cultures. Quantitative proteomic analysis indicates that control exosomes contain multiple functional signaling networks known to be important for neuronal circuit development. Treating MECP2-knockdown human primary neural cultures with control exosomes rescues deficits in neuronal proliferation, differentiation, synaptogenesis, and synchronized firing, whereas exosomes from MECP2-deficient hiPSC neural cultures lack this capability. These data indicate that exosomes carry signaling information required to regulate neural circuit development

Growth and activity of black holes in galaxy mergers with varying mass ratios

We study supermassive black holes (BHs) in merging galaxies, using a suite of hydrodynamical simulations with very high spatial (~10 pc) and temporal (~1 Myr) resolution, where we vary the initial mass ratio, the orbital configuration, and the gas fraction. (i) We address the question of when and why, during a merger, increased BH accretion occurs, quantifying gas inflows and BH accretion rates. (ii) We also quantify the relative effectiveness in inducing AGN activity of merger-related versus secular-related causes, by studying different stages of the encounter: the stochastic (or early) stage, the (proper) merger stage, and the remnant (or late) stage. (iii) We assess which galaxy mergers preferentially enhance BH accretion, finding that the initial mass ratio is the most important factor. (iv) We study the evolution of the BH masses, finding that the BH mass contrast tends to decrease in minor mergers and to increase in major mergers. This effect hints at the existence of a preferential range of mass ratios for BHs in the final pairing stages. (v) In both merging and dynamically quiescent galaxies, the gas accreted by the BH is not necessarily the gas with $low$ angular momentum, but the gas that $loses$ angular momentum.Comment: Accepted for publication in MNRAS, 23 pages, 22 figures, 3 table

Numerical Study of Three-dimensional Spatial Instability of a Supersonic Flat Plate Boundary Layer

The behavior of spatially growing three-dimensional waves in a supersonic boundary layer was studied numerically by solving the complete Navier-Stokes equations. Satisfactory comparison with linear parallel and non-parallel stability theories, and experiment are obtained when a small amplitude inflow disturbance is used. The three-dimensional unsteady Navier-Stokes equations are solved by a finite difference method which is fourth-order and second-order accurate in the convection and viscous terms respectively, and second-order accurate in time. Spanwise periodicity is assumed. The inflow disturbance is composed of eigenfunctions from linear stability theory. By increasing the amplitude of the inflow disturbance, nonlinear effects in the form of a relaxation type oscillation of the time signal of rho(u) are observed

On the gap-opening criterion of migrating planets in protoplanetary disks

We perform two-dimensional hydrodynamical simulations to quantitatively explore the torque balance criterion for gap-opening (as formulated by Crida et al. 2006) in a variety of disks when considering a migrating planet. We find that even when the criterion is satisfied, there are instances when planets still do not open gaps. We stress that gap-opening is not only dependent on whether a planet has the ability to open a gap, but whether it can do so quickly enough. This can be expressed as an additional condition on the gap-opening timescale versus the crossing time, i.e. the time it takes the planet to cross the region which it is carving out. While this point has been briefly made in the previous literature, our results quantify it for a range of protoplanetary disk properties and planetary masses, demonstrating how crucial it is for gap-opening. This additional condition has important implications for the survival of planets formed by core accretion in low mass disks as well as giant planets or brown dwarfs formed by gravitational instability in massive disks. It is particularly important for planets with intermediate masses susceptible to Type III-like migration. For some observed transition disks or disks with gaps, we expect that estimates on the potential planet masses based on the torque balance gap-opening criterion alone may not be sufficient. With consideration of this additional timescale criterion theoretical studies may find a reduced planet survivability or that planets may migrate further inwards before opening a gap.Comment: Accepted by ApJ, 22 pages, 13 figures, 6 table