An Experimental Investigation of Hypersonic Boundary-Layer Transition on Sharp and Blunt Slender Cones

Understanding the instabilities leading to the laminar-to-turbulent transition of a hypersonic boundary layer is a key challenge remaining for the design of efficient hypersonic vehicles. In the present study, experiments are performed in three different facilities at freestream Mach numbers between 6 and 14 to characterize instability mechanisms leading to transition on a 7-degree half-angle slender cone. Second-mode instability waves are visualized using a high-speed schlieren setup with the camera frame rate and spatial resolution optimized to allow individual disturbances to be tracked. In order to facilitate quantitative time-resolved measurements, a method of calibrating the schlieren system and novel image-processing algorithms have been developed. Good agreement is observed between the schlieren measurements, surface pressure measurements, and parabolized stability equation computations of the second-mode most-amplified frequencies and N factors. The high-frequency-resolution schlieren signals enable a bispectral analysis that reveals phase locking of higher harmonic content leading to nonlinear wave development. Individual disturbances are characterized using the schlieren wall-normal information not available from surface measurements. Experiments are also performed to investigate the effect of nose-tip bluntness. For moderate to large bluntness nose tips, second-mode instability waves are no longer visible, and elongated structures associated with nonmodal growth appear in the visualizations. The nonmodal features exhibit strong content between the boundary-layer and entropy-layer edges and are steeply inclined downstream. Simultaneously acquired surface pressure measurements reveal high-frequency pressure oscillations typical of second-mode instability waves associated with the trailing edge of the nonmodal features

Connections: A Journal of Public Education Advocacy - Fall 2003, Vol. 10, No. 1

President's Message - As the 50th anniversary of Brown v. Board of Education approaches, and state budget shortfalls continue, Wendy D. Puriefoy calls for "no child left behind" to become a sacred national commitment.Senator Kennedy on the Vision of Public Education - Sen. Edward M. Kennedy argues that the funding made available for school reform must be aligned with the goals set by NCLB.Making It Happen - Legal Defense Fund President Elaine R. Jones says courts must advance the cause of equity in schools to banish remnants of segregation that linger long after Brown.Viewpoint - Jack Jennings, director of the Center on Education Policy, played a role in implementing the Elementary and Secondary Education Act in the 1960s. Today he examines the policy and funding parallels between the original act and NCLB.Conversations - Peter McWalters, president-elect of the Council of Chief State School Officers; Angela Z. Monson, Oklahoma state senator; and Ted Sanders, president of the Education Commission of the States, discuss the many challenges states face in meeting NCLB requirements.End Notes - Richard Navarro, UNICEF's education chief, encourages international support to help Afghanistan rebuild its education system

Excimer laser coronary angioplasty in coronary lesions: Use and safety from the NCDR/CATH PCI Registry

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A scientific basis for restoring fish spawning habitat in the St. Clair and Detroit Rivers of the Laurentian Great Lakes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110848/1/rec12159.pd

'To live and die [for] Dixie': Irish civilians and the Confederate States of America

Around 20,000 Irishmen served in the Confederate army in the Civil War. As a result, they left behind, in various Southern towns and cities, large numbers of friends, family, and community leaders. As with native-born Confederates, Irish civilian support was crucial to Irish participation in the Confederate military effort. Also, Irish civilians served in various supporting roles: in factories and hospitals, on railroads and diplomatic missions, and as boosters for the cause. They also, however, suffered in bombardments, sieges, and the blockade. Usually poorer than their native neighbours, they could not afford to become 'refugees' and move away from the centres of conflict. This essay, based on research from manuscript collections, contemporary newspapers, British Consular records, and Federal military records, will examine the role of Irish civilians in the Confederacy, and assess the role this activity had on their integration into Southern communities. It will also look at Irish civilians in the defeat of the Confederacy, particularly when they came under Union occupation. Initial research shows that Irish civilians were not as upset as other whites in the South about Union victory. They welcomed a return to normalcy, and often 'collaborated' with Union authorities. Also, Irish desertion rates in the Confederate army were particularly high, and I will attempt to gauge whether Irish civilians played a role in this. All of the research in this paper will thus be put in the context of the Drew Gilpin Faust/Gary Gallagher debate on the influence of the Confederate homefront on military performance. By studying the Irish civilian experience one can assess how strong the Confederate national experiment was. Was it a nation without a nationalism

Galaxy and Mass Assembly (GAMA): the wavelength dependence of galaxy structure versus redshift and luminosity

We study how the sizes and radial profiles of galaxies vary with wavelength, by fitting Se´rsic functions simultaneously to imaging in nine optical and near-infrared bands. To quantify the wavelength dependence of effective radius we use the ratio, R, of measurements in two rest- frame bands. The dependence of Se´rsic index on wavelength, N , is computed correspondingly. Vulcani et al. have demonstrated that different galaxy populations present sharply contrasting behaviour in terms of R and N . Here we study the luminosity dependence of this result. We find that at higher luminosities, early-type galaxies display a more substantial decrease in effective radius with wavelength, whereas late types present a more pronounced increase in Se´rsic index. The structural contrast between types thus increases with luminosity. By considering samples at different redshifts, we demonstrate that lower data quality reduces the apparent difference between the main galaxy populations. However, our conclusions remain robust to this effect. We show that accounting for different redshift and luminosity selections partly reconciles the size variation measured by Vulcani et al. with the weaker trends found by other recent studies. Dividing galaxies by visual morphology confirms the behaviour inferred using morphological proxies, although the sample size is greatly reduced. Finally, we demonstrate that varying dust opacity and disc inclination can account for features of the joint distribution of R and N for late-type galaxies. However, dust does not appear to explain the highest values of R and N . The bulge–disc nature of galaxies must also contribute to the wavelength dependence of their structure. Key words: galaxies: formation – galaxies: fundamental parameters – galaxies: general – galaxies: structure

Incidence, management, and outcomes of cardiovascular insufficiency in critically ill term and late preterm newborn infants

OBJECTIVE: The objective of this study was to characterize the incidence, management, and short-term outcomes of cardiovascular insufficiency (CVI) in mechanically ventilated newborns, evaluating four separate prespecified definitions. STUDY DESIGN: Multicenter, prospective cohort study of infants ≥34 weeks gestational age (GA) and on mechanical ventilation during the first 72 hours. CVI was prospectively defined as either (1) mean arterial pressure (MAP) < GA; (2) MAP < GA + signs of inadequate perfusion; (3) any therapy for CVI; or (4) inotropic therapy. Short-term outcomes included death, days on ventilation, oxygen, and to full feedings and discharge. RESULTS: Of 647 who met inclusion criteria, 419 (65%) met ≥1 definition of CVI. Of these, 98% received fluid boluses, 36% inotropes, and 17% corticosteroids. Of treated infants, 46% did not have CVI as defined by a MAP < GA ± signs of inadequate perfusion. Inotropic therapy was associated with increased mortality (11.1 vs. 1.3%; p < 0.05). CONCLUSION: More than half of the infants met at least one definition of CVI. However, almost half of the treated infants met none of the definitions. Inotropic therapy was associated with increased mortality. These findings can help guide the design of future studies of CVI in newborn

Preferences for the Sex of Offspring and Demographic Behavior in Eighteenth- and Nineteenth-Century Germany: an Examination of Evidence From Village Genealogies

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68167/2/10.1177_036319908000500202.pd

Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network.

OBJECTIVE: This report presents data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network on care of and morbidity and mortality rates for very low birth weight infants, according to gestational age (GA). METHODS: Perinatal/neonatal data were collected for 9575 infants of extremely low GA (22-28 weeks) and very low birth weight (401-1500 g) who were born at network centers between January 1, 2003, and December 31, 2007. RESULTS: Rates of survival to discharge increased with increasing GA (6% at 22 weeks and 92% at 28 weeks); 1060 infants died at CONCLUSION: Although the majority of infants with GAs of \u3eor=24 weeks survive, high rates of morbidity among survivors continue to be observed