Smith-Purcell Radiation from Rough Surfaces

Radiation of a charged particle moving parallel to a inhomogeneous surface is considered. Within a single formalism periodic and random gratings are examined. For the periodically inhomogeneous surface we derive new expressions for the dispersion relation and the spectral-angular intensity. In particular, for a given observation direction two wavelengths are emitted instead of one wavelength of the standard Smith-Purcell effect. For a rough surface we show that the main contribution to the radiation intensity is given by surface polaritons induced on the interface between two media. These polaritons are multiply scattered on the roughness of surface and convert into real photons. The spectral-angular intensity is calculated and its dependence on different parameters is revealed.Comment: 6 pages, 2 figures, submitted to Phys. Rev. ST Accel. Beam

Grammateis und Mnamones:Schreiber und Rechtsbewahrer in archaischer und frühklassischer Zeit

Die Dissertation von Frank Reiche zeichnet die Ausdifferenzierung der Ämter der Mnamones (Rechtsbewahrer) und Grammateis (Schreiber) in archaischer und frühklassischer Zeit nach. Eingegangen wird auch auf die Folgewirkung dieser Entwicklung für den Prozess der Polisinstitutionalisierung. Quellengrundlage der Arbeit bilden vor allem inschriftliche Zeugnisse, die in den letzten Jahrzehnten neu gefunden und bisher nur wenig beachtet wurden

A chorus of different tongues: Official corporate language fluency and informal influence in multinational teams

Multinational team members commonly face challenges to influence their peers to attain shared work goals in a language different from their mother tongue. However, the mechanisms linking multinational team members’ official corporate language fluency and their displays of informal influence are not well understood. Drawing from status characteristics theory, we propose that peer-granted status mediates the relationship between fluency in the official corporate language and informal influence. We tested this prediction across two field studies and two experiments utilizing three different operationalizations of informal influence: voice behavior, voice quality, and leadership emergence. Overall, we demonstrate that members fluent in the official corporate language receive higher peer-granted status than their less fluent peers, and this relationship is stronger in teams whose members primarily converse in a common non-corporate language. In turn, high-status members engage in voice more frequently, and are more likely to convey voice quality and emerge as leaders

Employing electro-mechanical analogies for co-resonantly coupled cantilever sensors

Understanding the behaviour of mechanical systems can be facilitated and improved by employing electro-mechanical analogies. These analogies enable the use of network analysis tools as well as purely analytical treatment of the mechanical system translated into an electric circuit. Recently, we developed a novel kind of sensor set-up based on two coupled cantilever beams with matched resonance frequencies (co-resonant coupling) and possible applications in magnetic force microscopy and cantilever magnetometry. In order to analyse the sensor's behaviour in detail, we describe it as an electric circuit model. Starting from a simplified coupled harmonic oscillator model with neglected damping, we gradually increase the complexity of the system by adding damping and interaction elements. For each stage, various features of the coupled system are discussed and compared to measured data obtained with a co-resonant sensor. Furthermore, we show that the circuit model can be used to derive sensor parameters which are essential for the evaluation of measured data. Finally, the much more complex circuit representation of a bending beam is discussed, revealing that the simplified circuit model of a coupled harmonic oscillator is a very good representation of the sensor system

NcDNAlign: Plausible multiple alignments of non-protein-coding genomic sequences

Genome-wide multiple sequence alignments (MSAs) are a necessary prerequisite for an increasingly diverse collection of comparative genomic approaches. Here we present a versatile method that generates high-quality MSAs for non-protein-coding sequences. The NcDNAlign pipeline combines pairwise BLAST alignments to create initial MSAs, which are then locally improved and trimmed. The program is optimized for speed and hence is particulary well-suited to pilot studies. We demonstrate the practical use of NcDNAlign in three case studies: the search for ncRNAs in gammaproteobacteria and the analysis of conserved noncoding DNA in nematodes and teleost fish, in the latter case focusing on the fate of duplicated ultra-conserved regions. Compared to the currently widely used genome-wide alignment program TBA, our program results in a 20- to 30-fold reduction of CPU time necessary to generate gammaproteobacterial alignments. A showcase application of bacterial ncRNA prediction based on alignments of both algorithms results in similar sensitivity, false discovery rates, and up to 100 putatively novel ncRNA structures. Similar findings hold for our application of NcDNAlign to the identification of ultra-conserved regions in nematodes and teleosts. Both approaches yield conserved sequences of unknown function, result in novel evolutionary insights into conservation patterns among these genomes, and manifest the benefits of an efficient and reliable genome-wide alignment package. The software is available under the GNU Public License at http://www.bioinf.uni-leipzig.de/Software/NcDNAlign/

Analyzing the alignment of incentives, control, and economics in development agreements between private developers and mission-driven institutions

Thesis (S.M. in Real Estate Development)-Massachusetts Institute of Technology, Program in Real Estate Development in Conjunction with the Center for Real Estate, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 65-66).This thesis examines and analyzes the alignment of incentives, project control, and economics in development agreements between private developers and mission-driven institutions. Mission-driven institutions, such as churches, hospitals and universities, need to compete in their relative industries, and must leverage real estate assets as effectively as possible. In many cases, the best opportunities for underutilized institutional real estate is in the private market. In order to develop institutional real estate for the private market, institutions can partner with private development firms to utilize their knowledge and experience to maximize efficiency through complex development processes and create the best possible product for a given marketplace. This paper reviews existing literature on the topic of institutional-private development partnerships, then explains and analyzes two case studies: The Charles Street Jail, and a Market Rate Student Housing Project. The case studies act as real examples, and are used to examine the issues that can arise due to differences in incentives between private developers and mission-driven institutions, as well as possible ways that organizations can approach such concerns to mitigate associated risks.by F. Samuel Reiche.S.M.in Real Estate Developmen

Signal enhancement in cantilever magnetometry based on a co-resonantly coupled sensor

Cantilever magnetometry is a measurement technique used to study magnetic nanoparticles. With decreasing sample size, the signal strength is significantly reduced, requiring advances of the technique. Ultrathin and slender cantilevers can address this challenge but lead to increased complexity of detection. We present an approach based on the co-resonant coupling of a micro- and a nanometer-sized cantilever. Via matching of the resonance frequencies of the two subsystems we induce a strong interplay between the oscillations of the two cantilevers, allowing for a detection of interactions between the sensitive nanocantilever and external influences in the amplitude response curve of the microcantilever. In our magnetometry experiment we used an iron-filled carbon nanotube acting simultaneously as nanocantilever and magnetic sample. Measurements revealed an enhancement of the commonly used frequency shift signal by five orders of magnitude compared to conventional cantilever magnetometry experiments with similar nanomagnets. With this experiment we do not only demonstrate the functionality of our sensor design but also its potential for very sensitive magnetometry measurements while maintaining a facile oscillation detection with a conventional microcantilever setup