Servomechanism for Doppler shift compensation in optical correlator for synthetic aperture radar

A method and apparatus for correcting Doppler shifts in synthetic aperture radar data is described. An optical correlator for synthetic aperture radar data has a means for directing a laser beam at a signal film having radar return pulse intensity information recorded on it. A resultant laser beam passes through a range telescope, an azimuth telescope, and a Fourier transform filter located between the range and azimuth telescopes, and forms an image for recording on an image film. A compensation means for Doppler shift in the radar return pulse intensity information includes a beam splitter for reflecting the modulated laser beam, after having passed through the Fourier transform filter, to a detection screen having two photodiodes mounted on it

A Multi-Criteria Decision Framework for Animal Welfare Policy

Policy decisions aimed at improving farm animal welfare involve balancing several competing objectives. Not only do such decisions involve tradeoffs between social, ethical, economic and welfare considerations, animal welfare itself is a multi-dimensional concept and some husbandry practices may satisfy some welfare needs but fail to satisfy others. Multi-criteria decision analysis is a decision theoretic tool that has been used to inform decision making in fields such as environmental policy, urban and regional planning, and biosecurity – all of which are characterised by competing goals and multiple stake-holders. This paper presents a preliminary multi-criteria framework for the analysis of animal welfare policies at the national level using indoor housing options for layer hens as an empirical example. Preliminary results are presented, but major emphasis is placed on highlighting the information needed to make such a framework both transparent and tractable.Animal welfare, multi-criteria decision analysis, decision analysis, decision support, Agribusiness, Farm Management, Livestock Production/Industries,

Smallpox and Bioterrorism: Why the Plan to Protect the Nation Is Stalled and What to Do

The Iraq war is over, no weapons of mass destruction (WMD) have yet been found, and the president's smallpox plan, though sound, is running out of steam. Instead of being well on the way to protecting the nation's civilian population by vaccinating up to 10 million health, emergency, and public safety workers, we are stalled at 37,971 vaccinated civilians while the military has successfully and safely vaccinated more than 450,000 people. Moreover, whether or not WMD are found in Iraq, it is only one of a number of nations on the list of suspects. Of all biological weapons, smallpox has the greatest potential for doing widespread harm. Given that the risk of death or serious harm to anyone from any form of terrorism is very low, we should live our daily lives normally, not in fear. However, to do that we need to be sure that our government is taking effective steps to reduce the chances of terrorism and, when it occurs, to minimize its consequences. Even though there is enough vaccine for everyone, we are ill prepared to rapidly contain smallpox after a bioterrorist release. Although Centers for Disease Control and Prevention (CDC) guidelines have recently improved, they continue to overstate the risk of side effects of the vaccine and erroneously suggest that, after an attack, the techniques used decades ago to eradicate smallpox will work well today. Medicine and public health are very risk-averse professions in our risk-averse culture. We have not yet realized the complexity and difficulty of vaccinating millions of Americans rapidly after an attack. Nor have we come to grips with the need to make rapid, possibly draconian, post-attack decisions based on limited data of uncertain quality. That type of decisionmaking runs counter to the culture of public health. The Bush administration needs to revitalize our preparations for a smallpox bioterrorist event

The Centaurus A Northern Middle Lobe as a Buoyant Bubble

We model the northern middle radio lobe of Centaurus A (NGC 5128) as a buoyant bubble of plasma deposited by an intermittently active jet. The extent of the rise of the bubble and its morphology imply that the ratio of its density to that of the surrounding ISM is less than 10^{-2}, consistent with our knowledge of extragalactic jets and minimal entrainment into the precursor radio lobe. Using the morphology of the lobe to date the beginning of its rise through the atmosphere of Centaurus A, we conclude that the bubble has been rising for approximately 140Myr. This time scale is consistent with that proposed by Quillen et al. (1993) for the settling of post-merger gas into the presently observed large scale disk in NGC 5128, suggesting a strong connection between the delayed re-establishment of radio emission and the merger of NGC 5128 with a small gas-rich galaxy. This suggests a connection, for radio galaxies in general, between mergers and the delayed onset of radio emission. In our model, the elongated X-ray emission region discovered by Feigelson et al. (1981), part of which coincides with the northern middle lobe, is thermal gas that originates from the ISM below the bubble and that has been uplifted and compressed. The "large-scale jet" appearing in the radio images of Morganti et al. (1999) may be the result of the same pressure gradients that cause the uplift of the thermal gas, acting on much lighter plasma, or may represent a jet that did not turn off completely when the northern middle lobe started to buoyantly rise. We propose that the adjacent emission line knots (the "outer filaments") and star-forming regions result from the disturbance, in particular the thermal trunk, caused by the bubble moving through the extended atmosphere of NGC 5128.Comment: 38 pages, 13 figures, submitted to ApJ; a version with higher resolution figures is available at http://www.mso.anu.edu.au/~saxton/papers/cena.pd

Ecological and Sociological Considerations of Wind Energy: A Multidisciplinary Study

Wind energy is quickly becoming a critical technology for providing Americans with renewable energy, and rapid construction of wind facilities may have impacts on both wildlife and human communities. Understanding both the social and ecological issues related to wind energy development could provide a framework for effectively meeting human energy needs while conserving species biodiversity. In this research I looked at two aspects of wind energy development: public attitudes toward wind energy development and wind facility impacts on local bat populations. These papers present aspects of wind energy development that have been the subject of increasing study. This preliminary research is intended to demonstrate the responsibility we have to making well-informed decisions as we continue to expand wind energy development. Additionally, I hope to generate interest in interdisciplinary study as a means to broaden the scope of research by making use of the diverse tools available within different disciplines

Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. II. On the Nature of the Bipolar Outflow Asymmetry

The origin of bipolar outflow asymmetry in young stellar objects (YSOs) remains poorly understood. It may be due to an intrinsically asymmetric outflow launch mechanism, or it may be caused by the effects of the ambient medium surrounding the YSO. Answering this question is an important step in understanding outflow launching. We have investigated the bipolar outflows driven by the T Tauri star DG Tauri on scales of hundreds of AU, using the Near-infrared Integral Field Spectrograph (NIFS) on Gemini North. The approaching outflow consists of a well-collimated jet, nested within a lower-velocity disc wind. The receding outflow is composed of a single-component bubble-like structure. We analyse the kinemat- ics of the receding outflow using kinetic models, and determine that it is a quasi-stationary bubble with an expanding internal velocity field. We propose that this bubble forms because the receding counterjet from DG Tau is obstructed by a clumpy ambient medium above the circumstellar disc surface, based on similarities between this structure and those found in the modeling of active galactic nuclei outflows. We find evidence of interaction between the obscured counterjet and clumpy ambient material, which we attribute to the large molecular envelope around the DG Tau system. An analytical model of a momentum-driven bubble is shown to be consistent with our interpretation. We conclude that the bipolar outflow from DG Tau is intrinsically symmetric, and the observed asymmetries are due to environmental effects. This mechanism can potentially be used to explain the observed bipolar asymmetries in other YSO outflows.Comment: 16 pages, 10 figures, accepted for publication in MNRA

Interactions of Jets with Inhomogeneous Cloudy Media

We present two-dimensional slab-jet simulations of jets in inhomogeneous media consisting of a tenuous hot medium populated with a small filling factor by warm, dense clouds. The simulations are relevant to the structure and dynamics of sources such as Gigahertz Peak Spectrum and Compact Steep Spectrum radio galaxies, High Redshift Radio Galaxies and radio galaxies in cooling flows. The jets are disrupted to a degree depending upon the filling factor of the clouds. With a small filling factor, the jet retains some forward momentum but also forms a halo or bubble around the source. At larger filling factors channels are formed in the cloud distribution through which the jet plasma flows and a hierarchical structure consisting of nested lobes and an outer enclosing bubble results. We suggest that the CSS quasar 3C48 is an example of a low filling factor jet - interstellar medium interaction whilst M87 may be an example of the higher filling factor type of interaction. Jet disruption occurs primarily as a result of Kelvin-Helmholtz instabilities driven by turbulence in the radio cocoon not through direct jet-cloud interactions, although there are some examples of these. In all radio galaxies whose morphology may be the result of jet interactions with an inhomogeneous interstellar medium we expect that the dense clouds will be optically observable as a result of radiative shocks driven by the pressure of the radio cocoon. We also expect that the radio galaxies will possess faint haloes of radio emitting material well beyond the observable jet structure.Comment: 21 pages, 16 figures, submitted to MNRAS. A version with full resolution figures is available at: http://www.mssl.ucl.ac.uk/~cjs2/pdf/cloudy_hue.pd

Wideband high efficiency optical modulator Final report, 15 Feb. 1966 - 15 Mar. 1967

Design of wideband high efficiency optical modulation system tested over 100-MHz ban

The pulsed air gust generator Final report

Wind tunnel simulation of jet pulsing apparatus for controlled gust