Different expectations: a comparative history of structure, experience, and strategic alliances in the U.S. and U.K. poultry sectors, 1920-1990

This comparative historical analysis demonstrates how memory and reflexive interpretations of the past can shape entrepreneurial willingness to collaborate with larger firms in an industry. Emphasizing the importance of spatial metaphors and periodization for developing historical knowledge, the paper focuses on how the historical space of experience explains how entrepreneurs make strategic choices regarding collaboration under conditions of complexity and uncertainty. Comparing the U.S. and U.K. emerging poultry sectors offers a methodologically novel analysis of an important but little‐studied agribusiness sector, offering a dual reading that compares two versions of historical reasoning both theoretically and empirically

Three-cavity circuit studies of the Maryland gyroklystron

At the University of Maryland we have examined an X-Band TE{sub 01} mode three-cavity gyroklystron circuit that includes a tunable buncher cavity. The system parameters are: 425 kV, 100--200 A, pulse length {approximately} 1 {mu}s, operating frequency 9.85 GHz, and a beam alpha, {upsilon}{perpendicular}/{upsilon}{sub z}, in the range 0.7--1.0. This circuit produced a maximum power of 27 MW at 32% efficiency and a gain of 36 dB. We will summarize the major results of the three-cavity systems, including recent output cavity configurations that were to affect the post-cavity interaction

Design and cold testing of a high peak power x-band gyroklystron

The main goal of the University of Maryland's gyroklystron project is to develop an efficient, high power, high gain, phase controllable amplifier at 10 GHz. While peak powers of several hundred megawatts are ultimately of interest, our initial experimental design values include 30 MW of output power in 1 ..mu..s pulses with a gain in excess of 50 dB. The 30 MW power level represents an enhancement of almost three orders of magnitude over the current state-of-the-art in gyroklystron amplifiers. This enhancement will be achieved by going to high beam energies (..gamma..approx. =2) and overmoded cavities (TE/sub 01//sup 0/). Outlined in this report are the steps being taken to realize our goal

Replication of Polymer-Based Peptide Microarrays by Multi-Step Transfer

Peptide microarrays serve as a high-throughput tool for the readout of protein-peptide interactions. We present a multi-step purification of high-complexity peptide microarrays by transfer to specialized surfaces. Only correctly synthesized peptides are transferred from the synthesis surface to various substrates where they can be immobilized by a variety of different anchor molecules. Here, we demonstrate the transfer to rigid streptavidin, epoxide, gold, and azide surfaces. The reported method reduces the cost of purified peptide array production through the reproduction of one array several times

Replication of Polymer-Based Peptide Microarrays by Multi-Step Transfer

Peptide microarrays serve as a high-throughput tool for the readout of protein-peptide interactions. We present a multi-step purification of high-complexity peptide microarrays by transfer to specialized surfaces. Only correctly synthesized peptides are transferred from the synthesis surface to various substrates where they can be immobilized by a variety of different anchor molecules. Here, we demonstrate the transfer to rigid streptavidin, epoxide, gold, and azide surfaces. The reported method reduces the cost of purified peptide array production through the reproduction of one array several times