A European perspective on public debt

Public debt in Europe has risen continuously over the last two decades. How is the transition to European Economic and Monetary Union, with the increasing economic interdependence between individual member states which it involves, likely to affect this situation? Which policy issues are of particular relevance in this setting

Serial Block-Face Scanning Electron Microscopy to Reconstruct Three-Dimensional Tissue Nanostructure

Three-dimensional (3D) structural information on many length scales is of central importance in biological research. Excellent methods exist to obtain structures of molecules at atomic, organelles at electron microscopic, and tissue at light-microscopic resolution. A gap exists, however, when 3D tissue structure needs to be reconstructed over hundreds of micrometers with a resolution sufficient to follow the thinnest cellular processes and to identify small organelles such as synaptic vesicles. Such 3D data are, however, essential to understand cellular networks that, particularly in the nervous system, need to be completely reconstructed throughout a substantial spatial volume. Here we demonstrate that datasets meeting these requirements can be obtained by automated block-face imaging combined with serial sectioning inside the chamber of a scanning electron microscope. Backscattering contrast is used to visualize the heavy-metal staining of tissue prepared using techniques that are routine for transmission electron microscopy. Low-vacuum (20–60 Pa H(2)O) conditions prevent charging of the uncoated block face. The resolution is sufficient to trace even the thinnest axons and to identify synapses. Stacks of several hundred sections, 50–70 nm thick, have been obtained at a lateral position jitter of typically under 10 nm. This opens the possibility of automatically obtaining the electron-microscope-level 3D datasets needed to completely reconstruct the connectivity of neuronal circuits

Is a Federal European Constitution for an Enlarged European Union Necessary? Some Preliminary Suggestions Using Public Choice Analysis

In order to guarantee a further successful functioning of the enlarged European Union a Federal European Constitution is proposed. Six basic elements of a future European federal constitution are developed: the European commission should be turned into an European government and the European legislation should consist of a two chamber system with full responsibility over all federal items. Three further key elements are the subsidiarity principle, federalism and the secession right, which are best suited to limiting the domain of the central European authority to which certain tasks are given, such as defense, foreign and environmental policy. Another important feature is direct democracy, which provides the possibility for European voters to participate actively in the political decision making, to break political and interest group cartels, and to prevent an unwanted shifting of responsibilities from EU member states to the European federal level

A note on fiscal policy coordination in the European Monetary System

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 171603 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Resolution and Contrast Using the Backscattered Electron Signal

<div><p>(A and B) Presynaptic vesicles (SV) and postsynaptic folds (SF) are clearly visible (A) in a motor endplate preparation embedded in Spurr's resin. Similarly, the hexagonal array of actin filaments (AA) can be clearly resolved (B) in a different region from the same image (both images were smoothed using the ImageJ “smooth” command). Imaging conditions for (A) and (B): electron energy, 7.5 keV; spot, 3.5; chamber pressure, 30 Pa (H₂O); pixel dwell time, 30 μs. The scanning resolution was 6.7 nm/pixel.</p> <p>(C) The effect of beam exposure on the block surface. Note the increased brightness and the lack of chatter in the central region (inside the dashed rectangle), from which a stack was acquired at higher resolution before taking the image shown. The tissue was rat neocortex embedded in Spurr's resin. Imaging conditions for (C): electron energy, 7.5 keV; spot, 3; digital resolution for stack acquisition, 26.7 nm/pixel; dwell time, 30 μs.</p> <p>(D and E) Cortical tissue embedded in Epon. Synapses (SD) are clearly discernable (E). Imaging conditions for (D) and (E): electron energy, 7.5 keV beam current; spot, 3; chamber pressure, 30Pa (H₂O); pixel dwell time, 30 μs. The scanning resolution was 9.5 nm/pixel.</p> <p>Note that more backscattering corresponds to darker pixels in (A), (B), (D), and (E) but to brighter pixels in (C).</p></div

The Alignment of Successive Images in a Stack

<div><p>Shifts between images were quantified using the positions of the peaks of the cross correlation (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020329#s4" target="_blank">Materials and Methods</a>); same dataset as in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020329#pbio-0020329-g003" target="_blank">Figure 3</a>A and <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020329#pbio-0020329-g003" target="_blank">3</a>B.</p> <p>(A) The peak shifts in x-direction are shown for five different subregions distributed over the field of view. Four of the regions have a size of 256 × 256 pixels, one has a size of 512 × 512 (black trace). The peaks around slices 59 and 202 are caused by slice debris on the block face (see also streaks in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0020329#pbio-0020329-g003" target="_blank">Figure 3</a>B).</p> <p>(B) The x/y displacement for the 512 × 512 region is shown in a scatter plot. For the central cluster the standard deviations are 10.9 nm and 11.8 nm for x and y, respectively.</p></div