Structure of the cell envelope of Halobacterium halobium

The structure of the isolated cell envelope of Halobacterium halobium is studied by X-ray diffraction, electron microscopy, and biochemical analysis. The envelope consists of the cell membrane and two layers of protein outside. The outer layer of protein shows a regular arrangement of the protein or glycoprotein particles and is therefore identified as the cell wall. Just outside the cell membrane is a 20 A-thick layer of protein. It is a third structure in the envelope, the function of which may be distinct from that of the cell membrane and the cell wall. This inner layer of protein is separated from the outer protein layer by a 65 Å-wide space which has an electron density very close to that of the suspending medium, and which can be etched after freeze-fracture. The space is tentatively identified as the periplasmic space. At NaCl concentrations below 2.0 M, both protein layers of the envelope disintegrate. Gel filtration and analytical ultracentrifugation of the soluble components from the two protein layers reveal two major bands of protein with apparent mol wt of ~16,000 and 21,000. At the same time, the cell membrane stays essentially intact as long as the Mg++ concentration is kept at ≥ 20 mM. The cell membrane breaks into small fragments when treated with 0.1 M NaCl and EDTA, or with distilled water, and some soluble proteins, including flavins and cytochromes, are released. The cell membrane apparently has an asymmetric core of the lipid bilayer

Formation of Low Threshold Voltage Microlasers

Vertical cavity surface emitting lasers (VCSELs) with threshold voltages of 1.7V have been fabricated. The resistance-area product in these new vertical cavity lasers is comparable to that of edge-emitting lasers, and threshold currents as low as 3 mA have been measured. Molecular beam epitaxy was used to grow n-type mirrors, a quantum well active region, and a heavily Be-doped p-contact. After contact definition and alloying, passive high-reflectivity mirrors were deposited by reactive sputter deposition of SiO2/Si3N4 to complete the laser cavity

Holderlins Einsamkeit und Dichtertum

Paper by Walther L. Hahn, Associate Professor of German at the University of Orego

The Unification of Europe after the Second World War: Challenges in a Globalized World

The essay analyzes the process of European unification after the Second World War. It starts with the enormous distrust that had most of the European states towards Germany, and it explains how, in the following decades, this distrust diminished slowly. Nevertheless, it did not disappear completely, what could be seen clearly in the process of German reunification after the fall of the Wall of Berlin. Furthermore, the essay underlines that the European Union has been built from one crisis to another, and all these crises finally have contributed to strengthen the idea of the European unity.El ensayo analiza a grandes rasgos el proceso de unificación europea después de la Segunda Guerra Mundial, partiendo de la enorme desconfianza que reinaba en Europa en 1945 frente a Alemania. Explica cómo, paso a paso, esta desconfianza disminuyó a lo largo de las décadas, pero sin desaparecer completamente, lo que se puso nuevamente de manifiesto en el proceso de reunificación alemana después de la caída del Muro de Berlín. Resalta, además, que Europa se ha venido construyendo de crisis a crisis; todas estas crisis han contribuido, a fin de cuentas, a fortalecer la idea de la unidad Europea

MatlabTA: A Style Critiquer For Novice Engineering Students

Novice programmers, considered to be those who have yet to understand the fundamentals of programming, exist in both engineering and computing fields. Within computing, various resources exist to help novice programmers understand fundamentals and style guidelines such as WebTA, a code critique program that gives Java students feedback about their error and style issues. There is, however, a gap in automated code critique for MATLAB, a programming language that is popular in the engineering community. When it comes to MATLAB, there are not many programs that help novices understand their errors, and even fewer that help them understand style guidelines. To help assist these engineering novices, I created a program called MatlabTA. Based on feedback from Engineering Fundamentals instructors on the most common errors they encounter in student code, MatlabTA exists to give novices more intuitive feedback for a few of the most common MATLAB errors, along with providing them different style guidelines for different MATLAB antipatterns such as inconsistent tabbing and function output variable matching. This report will provide an overview of the process in developing MatlabTA, along with examples of the different outputs the application produces

Quantum-Matter-Spacetime : Peter Mittelstaedt's Contributions to Physics and Its Foundations

In a period of over 50 years, Peter Mittelstaedt has made substantial and lasting contributions to several fields in theoretical physics as well as the foundations and philosophy of physics. Here we present an overview of his achievements in physics and its foundations which may serve as a guide to the bibliography (printed in this Festschrift) of his publications. An appraisal of Peter Mittelstaedt's work in the philosophy of physics is given in a separate contribution by B. Falkenburg