Frequency, intensity, and field fluctuations in laser oscillators

The basic differential equation governing laser noise is derived from classical and quantum mechanical considerations. Its linearized Van Der Pol form is used to derive the frequency, field, and intensity fluctuation spectra

Characterizing and testing a thermally isolating superconducting link for SAFIRE-like missions

The recent discovery of high temperature ceramic superconductors with transition temperatures above 90 K has opened the possibilities for new space applications. One application is the fabrication of an electrically conducting and thermally isolating electronic link to connect IR detectors to data acquisition electronics on remote sensing platforms. The Spectroscopy of the Atmosphere using Far Infra-Red Emission (SAFIRE) mission is an example of a platform which employs hybrid dewars and combines both mechanical and cryogenic liquid cooling. This new technology is limited by the heat conducted through sensor array leads that connect the electronics (at approximately 80 K) to the sensors (at approximately 4 K). This link must be made of material that has high electrical conductivity and high thermal resistance. The YBa2Cu3O(x) superconductor with a transition temperature, T(sub c), of 93 K can achieve these conflicting requirements. A link with these characteristics will improve the thermal isolation of IR detectors and will increase the lifetime of the cryogen. A reduction of the thermal load due to the link by a factor of four will increase the lifetime of a seven year mission by about one year

Predicting Axonal Response to Molecular Gradients with a Computational Model of Filopodial Dynamics

Axons are often guided to their targets in the developing nervous system by attractive or repulsive molecular concentration gradients. We propose a computational model for gradient sensing and directed movement of the growth cone mediated by filopodia. We show that relatively simple mechanisms are sufficient to generate realistic rajectories for both the short-term response of axons to steep gradients and the long-term response of axons to shallow gradients. The model makes testable predictions for axonal response to attractive and repulsive gradients of different concentrations and steepness, the size of the intracellular amplification of the gradient signal, and the differences in intracellular signaling required for repulsive versus attractive turning

A comparison of superconductor and manganin technology for electronic links used in space mission applications

The electronic link connecting cryogenically cooled radiation detectors to data acquisition and signal processing electronics at higher temperatures contributes significantly to the total heat load on spacecraft cooling systems that use combined mechanical and cryogenic liquid cooling. Using high transition temperature superconductors for this link has been proposed to increase the lifetime of space missions. Herein, several YBCO (YBa2Cu3O7) superconductor-substrate combinations were examined and total heat loads were compared to manganin wire technology in current use. Using numerical solutions to the heat-flow equations, it is shown that replacing manganin technology with YBCO thick film technology can extend a 7-year mission by up to 1 year

The paradox of success: the roll of capital markets in determining British policy toward the European common currency, 1979-1996

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 24-25).That Britain, one of Europe's largest economies, has opted not to adopt the European common currency (Euro) has puzzled students of the European Union for some time. As recent referenda demonstrate, Britons remain mysteriously cautious of monetary integration with mainland Europe. Though existing literature often attributes Britons' Euro-skepticism to nationalism or xenophobia, few have examined the role of economic concerns in determining British attitudes toward the Euro. Drawing on methodology developed by Perry and Robertson (2000), this study examines the role of capital markets in determining British attitudes toward the Euro. Specifically, using annual Euro-barometer and exchange rate data over the period 1979-1996, this study examines whether the Euro-Pound exchange rate plays a role in creating a pro- or anti-Euro political environment in Britain. Based on the assumption that, ceteris paribus, a pro-Euro political environment will likely result in pro-Euro policy, this study enables us to assess the effect of exchange rates on British policy toward the common currency. The study finds that, indeed, exchange rates do help shape the British political landscape - as the Euro flounders, British opinion toward the Euro sours; when the Euro outperforms the British Pound, Britons tend to acquiesce toward the notion of monetary integration

Acetabular revision with freeze-dried irradiated and chemically treated allograft: a minimum 5-year follow-up of 17 cases

We reviewed the results of 17 consecutive revision total hip arthroplasties performed with the use of freeze-dried irradiated bone allograft in 15 patients. These allografts were used in conjunction with five Kerboull rings, two steel meshes and ten cemented isolated cups. All the patients have had a follow-up of at least 5years. The patients were evaluated clinically and radiographically. No revisions were necessary and X-rays confirmed partial or total ingrowth of the allografts. In acetabular revision surgery, hip reconstruction can be successfully treated by freeze-dried irradiated and chemically treated allografts. Additional studies with longer term follow-up are necessary to confirm this outcom

General practice registrars’ intentions for future practice: Implications for rural medical workforce planning

The models of practice that general practice registrars (GPRs) envisage undertaking will affect workforce supply. The aim of this research was to determine practice intentions of current GPRs in a regional general practice training program (Coast City Country General Practice Training). Questionnaires were circulated to 220 GPRs undertaking general practice placements to determine characteristics of ideal practice models and intentions for future practice. Responses were received for 99 participants (45%). Current GPRs intend to work an average of less than eight half-day sessions/week, with male participants intending to work more hours (t(91) = 3.528, P = 0.001). More than one-third of this regional cohort intends to practice in metropolitan centres. Proximity to family and friends was the most important factor influencing the choice of practice location. Men ranked remuneration for work as more important (t (88) = –4.280, P \u3c 0.001) and women ranked the ability to work part-time higher (t(94) = 3.697, P \u3c 0.001). Fee-for-service payment alone, or in combination with capitation, was the preferred payment system. Only 22% of Australian medical graduates intend to own their own practice compared with 52% of international medical graduates (χ2(1) = 8.498, P = 0.004). Future general practitioners (GPs) intend to work fewer hours than current GPs. Assumptions about lifestyle factors, practice models and possible professional roles should be carefully evaluated when developing strategies to recruit GPs and GPRs into rural practice

U.S. outward FDI: Current flows lowered in weakened global economy but attraction of emerging markets remains

The pronounced decline in U.S. OFDI parallels the broader falloff in business investment worldwide in the current economic recession. Despite the slowdown in U.S. OFDI flows, they remained over 25 percent higher than the average for the preceding five years, which is partly attributable to the continuing attraction of big emerging markets