Structural dynamic testing of composite propfan blades for a cruise missile wind tunnel model

The Naval Weapons Center at China Lake, California is currently evaluating a counter rotating propfan system as a means of propulsion for the next generation of cruise missiles. The details and results of a structural dynamic test program are presented for scale model graphite-epoxy composite propfan blades. These blades are intended for use on a cruise missile wind tunnel model. Both dynamic characteristics and strain operating limits of the blades are presented. Complications associated with high strain level fatigue testing methods are also discussed

Parent and Student Voices on the First Year of the DC Opportunity Scholarship Program

In the 50 years since economist Milton Friedman published “The Role of Government in Education” scholars and policy makers have been debating how parental choice through market mechanisms can and does operate in education. Market “optimists” argue that education is a service that can be produced under a variety of arrangements and that parents are natural education consumers. Market “pessimists” argue that education is a public good that should be produced in government-run schools, and that school choice programs suffer “market failure” because only advantaged families will have the resources and experience to choose effectively

Evidence-based Decision-making in Canada’s Protected Areas Organizations: Implications for Management Effectiveness

Aichi Biodiversity Target 19 calls on Parties to the United Nations Convention on Biological Diversity (CBD) to improve, share, transfer, and apply knowledge. In this study, we provide an initial assessment of the state of evidence-based decision-making in Canada’s protected areas organizations by examining (1) the value and use of various forms of evidence by managers and (2) the extent to which institutional conditions enable or inhibit the use of evidence in decision-making. Results revealed that although managers value and use many forms of evidence in their decision-making, information produced by staff and their organizations are given priority. Other forms of evidence, such as Indigenous knowledge and peer-reviewed information, are valued and used less. The most significant barriers to evidence-based decision-making were limited financial resources, lack of staff, inadequate timeframes for decision-making, a lack of monitoring programs, and a disconnect between researchers and decision-makers. Overall, our results suggest that the potential benefits of evidence-based approaches are not being maximized in Canada’s protected areas organizations. We propose several recommendations to introduce or improve the use of diverse forms of evidence to enhance management effectiveness of Canada’s protected areas and by extension conservation outcomes

Limits on [OIII] 5007 emission from NGC4472's globular clusters: constraints on planetary nebulae and ultraluminous black hole X-ray binaries in globular clusters

We have searched for [OIII] 5007 emission in high resolution spectroscopic data from Flames/Giraffe VLT observations of 174 massive globular clusters (GCs) in NGC4472. No planetary nebulae (PNe) are observed in these clusters, constraining the number of PNe per bolometric luminosity, \alpha<0.8*10^{-7}PN/L_{\odot}. This is significantly lower than the rate predicted from stellar evolution, if all stars produce PNe. Comparing our results to populations of PNe in galaxies, we find most galaxies have a higher \alpha than these GCs (more PNe per bolometric luminosity - though some massive early-type galaxies do have similarly low \alpha). The low \alpha required in these GCs suggests that the number of PNe per bolometric luminosity does not increase strongly with decreasing mass or metallicity of the stellar population. We find no evidence for correlations between the presence of known GC PNe and either the presence of low mass X-ray binaries (LMXBs) or the stellar interaction rates in the GCs. This, and the low \alpha observed, suggests that the formation of PNe may not be enhanced in tight binary systems. These data do identify one [OIII] emission feature, this is the (previously published) broad [OIII] emission from the cluster RZ 2109. This emission is thought to originate from the LMXB in this cluster, which is accreting at super-Eddington rates. The absence of any similar [OIII] emission from the other clusters favors the hypothesis that this source is a black hole LMXB, rather than a neutron star LMXB with significant geometric beaming of its X-ray emission.Comment: 10 pages, 3 figures, accepted for publication in Ap

Art and Medicine: A Collaborative Project Between Virginia Commonwealth University in Qatar and Weill Cornell Medicine in Qatar

Four faculty researchers, two from Virginia Commonwealth University in Qatar, and two from Weill Cornell Medicine in Qatar developed a one semester workshop-based course in Qatar exploring the connections between art and medicine in a contemporary context. Students (6 art / 6 medicine) were enrolled in the course. The course included presentations by clinicians, medical engineers, artists, computing engineers, an art historian, a graphic designer, a painter, and other experts from the fields of art, design, and medicine. To measure the student experience of interdisciplinarity, the faculty researchers employed a mixed methods approach involving psychometric tests and observational ethnography. Data instruments included pre- and post-course semi-structured audio interviews, pre-test / post-test psychometric instruments (Budner Scale and Torrance Tests of Creativity), observational field notes, self-reflective blogging, and videography. This book describes the course and the experience of the students. It also contains images of the interdisciplinary work they created for a culminating class exhibition. Finally, the book provides insight on how different fields in a Middle Eastern context can share critical /analytical thinking tools to refine their own professional practices

Growth in the Real Size of Government since 1970

From at least 1893 economists have viewed income as an important determinant of government size and the hypothesis that government size increases with income is now enshrined in the literature as Wagner’s Law. More recently, however, public choice economists and growth theorists have tended to reverse that causality by questioning whether government size is a constraint on (or promulgator of) economic growth. Typically, increases in government size arising from increased consumption are viewed as constraints on growth, while increases in size that arise from government investment are viewed as positive in their effect on growth. In this paper we are concerned with the two-way interrelationship between government size and income growth highlighted by these separate literatures and investigate this relationship in three distinct stages. In the first part of the paper we set out what has actually happened to the real size of government for twenty OECD countries over the period since 1970 and survey some of the newer factors and approaches used to explain its more recent evolution. The second part re-estimates the parameters of the demand curve for government allows us to speculate whether the changing pattern of government growth represents a break in the structure of the model determining government size or, more simply, represents a change in the variation of the underlying variables. We find that the same model works at least as well as it did in earlier periods with coefficients that are close to their earlier estimates. We follow this by estimating a simple growth model that highlights the size of government consumption in relation to income and output growth for the same countries over the same time period. Increases in size do appear to constrain economic growth. The third part of our paper recognizes that while each of the two causal relationships has received considerable attention in their own right, less attention has been given to effecting a separation of their co-mingled effects. To do so, we estimate the two relationships simultaneously in the context of our panel. This allows us assess whether ignoring the simultaneity of the two-way relationship seriously biases the measure of either the income effect (in determining government size) and/or the measure of government’s effect on economic growth when each are estimated separately. While our discussion suggests that single equation estimates of the income elasticity in Wagner’s Law may have been biased upwards (in absolute terms) and the constraining effect of government size on growth biased downwards, our three stage estimates finds only modest support in the data. The paper concludes by exploring the interrelationship between government size and government regulation. In particular, we test the hypothesis that the appearance of slower growth in government side is due to the increased substitution of indirect control of private production for direct governmental output. On cross sectional data, we find the opposite. In our sample, larger government size is associated with more rather than less regulation.

Some Constraints On the Effects of Age and Metallicity on the Low Mass X-ray Binary Formation Rate

We have studied the low mass X-ray binary (LMXB) populations within and outside globular clusters (GC) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate age cluster population of NGC 4365, as has been proposed in some scenarios of dynamical LMXB formation in GCs. The old, metal-rich, red population of GCs in NGC 3115 on the other hand is {\it at least} three times as efficient at creating LMXBs as the old, metal-poor, blue clusters. These data suggest that the higher formation efficiency of LMXBs in the red GC subsystems of many galaxies is largely a consequence of their higher metallicity. A comparison of the densities of field LMXBs in different galaxies does not reveal an obvious correlation with the age of the field stars as predicted by models in which the LMXB formation rate in the field drops monotonically with time after an initial burst. This suggests that either a significant fraction of the field LMXBs are created in GCs and subsequently injected into the field, or the LMXB formation rate has a more complex time evolution pattern.Comment: Accepted for publication in ApJ Letters. 7 pages including 5 figure