Extreme Star Formation

Extreme star formation includes star formation in starbursts and regions forming super star clusters. We survey the current problems in our understanding of the star formation process in starbursts and super star clusters - initial mass functions, cluster mass functions, star formation efficiencies, and radiative feedback into molecular clouds - that are critical to our understanding of the formation and survival of large star clusters, topics that will be the drivers of the observations of the next decade.Comment: appeared in "Astrophysics in the Next Decade: JWST and Concurrent Facilities", Astrophysics and Space Science Proceedings, 2009, ed. H. A. Thronson, M. Stiavelli, and A. G. G. M. Tielens, proceedings of the conference, Astrophysics in the Next Decade, 24-27 September 2007, Tucson, A

Remembering Lee Ann in South Africa: Meta-data and reflexive research practice

Lee Ann Fujii and I became fast friends, colleagues, and disciplinary comrades soon after we met at the 2004 Institute for Qualitative and Multi-Method Research (IQMR). IQMR presentations and workshops sparked fourteen years of conversation about the discipline, our positionality with respect to the discipline and research participants, methodologies, the “field,” and much more. Lee Ann made me laugh and encouraged me to think harder as we talked over coffee and chocolate at home in Oakland, New York, Washington, DC, Indianapolis, and Toronto; met up at APSA annual meetings; and practiced yoga together

Graduate perceptions of a UK university based coach education programme, and impacts on development and employability

This investigation explored graduates’ perceptions and experiences of a Higher Education (HE) coach education programme. It aimed to identify if this formal learning source had impacted upon attendees’ development and employability, while uncovering information to potentially inform future provision. 10 graduate coaches who had completed coaching modules at a United Kingdom (UK) HE institution participated in in-depth semi-structured interviews. Graduate coaches highlighted a positive educational experience that developed critical analytical skills, assisted in their perceived accelerated development, and enhanced employability. Using Carl Rogers’ work as a framework to analyse the data, it is demonstrated that the findings collectively offer implicit support for the adoption of a person-centred educational philosophy. Further research and debate is identified as necessary to ascertain whether the person-centred approach offers a legitimate and effective alternative form of coach education.Peer reviewe

X-ray reverberation in NLS1

Reverberation from scattering material around the black hole in active galactic nuclei is expected to produce a characteristic signature in a Fourier analysis of the time delays between directly-viewed continuum emission and the scattered light. Narrow-line Seyfert 1 galaxies (NLS1) are highly variable at X-ray energies, and are ideal candidates for the detection of X-ray reverberation. We show new analysis of a small sample of NLS1 that clearly shows the expected time-delay signature, providing strong evidence for the existence of a high covering fraction of scattering and absorbing material a few tens to hundreds of gravitational radii from the black hole. We also show that an alternative interpretation of time delays in the NLS1 1H0707-495, as arising about one gravitational radius from the black hole, is strongly disfavoured in an analysis of the energy-dependence of the time delays.Comment: Published online in Proceedings of Science, "Narrow-line Seyfert 1 Galaxies and their place in the Universe", held in Milan, Italy April 4-6, 201

Statistics of Extreme Gravitational Lensing Events. I.The Zero Shear Case

For a given source and lens pair, there is a thin on-axis tube-like volume behind the lens in which the radiation flux from the source is greatly increased due to gravitational lensing. Any objects (such as dust grains) which pass through such a thin tube will experience strong bursts of radiation, i.e., Extreme Gravitational Lensing Events (EGLE). We study the physics and statistics of EGLE for the case in which finite source size is more important than shear. One of the several possible significant astrophysical effects is investigated with an illustrative calculation.Comment: revised and final published version including a new section on the destruction of dust grains in globular clusters as an exampl

Helicopters as a Theme in a Machine Design Course

Helicopters as a Theme in Teaching Machine Design A machine design course is required in most undergraduate mechanical engineering curricula.This course generally covers an introduction to mechanical engineering design, a review of materials engineering, a review of mechanics of materials (shear force and bending moment diagrams, stress and strain analysis, deflection and stiffness analysis of beams, columns, etc.),models for failure due to static loading and variable fatigue, and then presents (in somewhat arbitrary order) the design of specific mechanical elements: shafts, fasteners, springs, bearings,gears, flexible elements such as belts, chain, and wire rope, clutches, brakes, couplings, etc.For some topics in machine design it is not possible to develop analytical models from first principles, as is done in fluid mechanics or thermodynamics. Rather, there are guidelines and rules of thumb and equations that include factors that must be taken on blind faith and somehow used to get an approximate answer. The approach can be unsatisfying, arbitrary, and not meaningful unless it is tied to real-world problems.To help motivate student learning, foster interest in the topics, and make the material more alive,we are testing the idea of studying helicopters and their components throughout the course as a theme to teach students about the different mechanical elements. Helicopters are an ideal system to exemplify the concepts taught in the course because all aspects of machine design are encapsulated in the design of a helicopter and the price of failure of the components or design is high (human fatality). In the standard helicopter configuration, two turbine jet engines are used to drive a main rotor and a tail rotor and the pilot controls are mechanically linked to both rotors to allow for handling of the aircraft.For each topic in the course the connection to helicopters is presented and helicopter design challenges are posed. For example, the shafts and gearboxes used to transfer energy from the high-speed turbine engines to the low speed rotors can be used to teach students about shaft bending, gear design, and fatigue failure. When asked to design a gearbox to achieve the speed reduction between the turbine jet engine and the main rotor, students discover why planetary gears are used. Other topics such as clutches, brakes, couplings, fasteners, springs, and vibration effects are all prominent features of helicopter design. They serve as excellent motivating examples to show students the real-life applications of machine design concepts.In closing, students generally view the machine design course as very challenging and, due to themany specific machine elements covered, have difficulty seeing how the separate components fit within the needs for a real system. To address this concern, enhance learning, and bring more excitement to the topics, we explored the value of using a theme physical system, namely helicopters and their components, to bring the material to life when teaching machine design

Mapping islands, reefs and shoals in the oceans surrounding Australia

The author has identified the following significant results. Comparisons of the imagery with aerial photography of areas of reefs and island and with 1:250,000 maps of coastlines indicate that the MSS imagery depicts detail to an extent which is satisfactory for 1:250,000 mapping. As the imagery does not have some of the disadvantages of aerial photography, the former should be valuable for mapping reefs, islands, and shoals. The water discoloration problem is significant as the discolored water appears to occur near shallow depths, so that confusion could arise through the misinterpretation of discolored water, when it exists, as shallow water