Superpressure balloon flights from Christchurch, New Zealand, July 1968 - December 1969

Strain gages on superpressure balloon flights from Christchurch, New Zealand - Jul. 1968 to Dec. 196

An agent-based intelligent tutoring system for nurse education

This report describes the development of a teaching environment that uses agents to support learning. An Intelligent Tutoring System will be described, that guides students during learning. This system is meant for nurse education in the first place, but it is generic in the sense that the core is separated from the exercise modules and user interfaces. This means that the system can also be used for other (non-nursing) exercises. Exercises can be provided to the system in the form of XML data-files. A user interface can be text-based or 2D, but it can also be a 3D virtual reality environment. An application of the teaching environment for nurse training is described

A quantitative study of spin noise spectroscopy in a classical gas of 41^{41}K atoms

We present a general derivation of the electron spin noise power spectrum in alkali gases as measured by optical Faraday rotation, which applies to both classical gases at high temperatures as well as ultracold quantum gases. We show that the spin-noise power spectrum is determined by an electron spin-spin correlation function, and we find that measurements of the spin-noise power spectra for a classical gas of $^{41}$K atoms are in good agreement with the predicted values. Experimental and theoretical spin noise spectra are directly and quantitatively compared in both longitudinal and transverse magnetic fields up to the high magnetic field regime (where Zeeman energies exceed the intrinsic hyperfine energy splitting of the $^{41}$K ground state)

Circular-Polarization Dependent Cyclotron Resonance in Large-Area Graphene in Ultrahigh Magnetic Fields

Using ultrahigh magnetic fields up to 170 T and polarized midinfrared radiation with tunable wavelengths from 9.22 to 10.67 um, we studied cyclotron resonance in large-area graphene grown by chemical vapor deposition. Circular-polarization dependent studies reveal strong p-type doping for as-grown graphene, and the dependence of the cyclotron resonance on radiation wavelength allows for a determination of the Fermi energy. Thermal annealing shifts the Fermi energy to near the Dirac point, resulting in the simultaneous appearance of hole and electron cyclotron resonance in the magnetic quantum limit, even though the sample is still p-type, due to graphene's linear dispersion and unique Landau level structure. These high-field studies therefore allow for a clear identification of cyclotron resonance features in large-area, low-mobility graphene samples.Comment: 9 pages, 3 figure

Photoluminescence studies of modulation doped coupled double quantum wells in magnetic fields

We have studied the photoluminescence spectra of a series of mudulation doped couple double quantum well structures in parallel and perpendicular magnetic fields to 62 tesla at 4K and 77K, for B{parallel}a, the spectra display distinct Landau level transitions which show anti-crossing with the e1-hh1 exciton. At high fields, the lowest conduction band-valence exciton approaches the extrapolated 0- 0 Landau level. About 25 Tesla, there is valence band mixing of the e1-lh1, e1-hh2, e1-hh1 transitions. The spectral peaks display a diamagnetic shift in low in-plane magnetic fields which become linear in high fields. At magnetic fields beyond 40T, spin splitting is observed for both B{parallel}z and B{perpendicular} geometries. The partial energy gap discovered in conductance measurements in in-plane fields was not conclusively observed using photoluminescence spectroscopy, although anomalies in the energy dependence of the lowest level with magnetic field were evident at similar field values

Experimental determination of B-T phase diagram of YBa_2Cu_3O_7-d to 150T for B perpendicular to c

The B-T phase diagram for thin film YBa_2Cu_3O_7-d with B parallel to the superconducting layers has been constructed from GHz transport measurements to 150T. Evidence for a transition from a high T regime dominated by orbital effects, to a low T regime where paramagnetic limiting drives the quenching of superconductivity, is seen. Up to 110T the upper critical field is found to be linear in T and in remarkable agreement with extrapolation of the longstanding result of Welp et al arising from magnetisation measurements to 6T. Beyond this a departure from linear behaviour occurs at T=74K, where a 3D-2D crossover is expected to occur.Comment: 4 pages, 4 figure

Long-term IL-33-producing epithelial progenitor cells in chronic obstructive lung disease

Chronic obstructive lung disease is characterized by persistent abnormalities in epithelial and immune cell function that are driven, at least in part, by infection. Analysis of parainfluenza virus infection in mice revealed an unexpected role for innate immune cells in IL-13–dependent chronic lung disease, but the upstream driver for the immune axis in this model and in humans with similar disease was undefined. We demonstrate here that lung levels of IL-33 are selectively increased in postviral mice with chronic obstructive lung disease and in humans with very severe chronic obstructive pulmonary disease (COPD). In the mouse model, IL-33/IL-33 receptor signaling was required for Il13 and mucin gene expression, and Il33 gene expression was localized to a virus-induced subset of airway serous cells and a constitutive subset of alveolar type 2 cells that are both linked conventionally to progenitor function. In humans with COPD, IL33 gene expression was also associated with IL13 and mucin gene expression, and IL33 induction was traceable to a subset of airway basal cells with increased capacities for pluripotency and ATP-regulated release of IL-33. Together, these findings provide a paradigm for the role of the innate immune system in chronic disease based on the influence of long-term epithelial progenitor cells programmed for excess IL-33 production

Magnetic susceptibility of the normal-superconducting transition in high-purity single-crystal α-uranium

We report complex ac magnetic susceptibility measurements of a superconducting transition in very high-quality single-crystal alpha-uranium using microfabricated coplanar magnetometers. We identify an onset of superconductivity at Tapproximate to0.7 K in both the real and imaginary components of the susceptibility which is confirmed by resistivity data. A superconducting volume fraction argument, based on a comparison with a calibration YBa2Cu3O7-delta sample, indicates that superconductivity in these samples may be filamentary. Our data also demonstrate the sensitivity of the coplanar micro-magnetometers, which are ideally suited to measurements in pulsed magnetic fields exceeding 100 T

Development and Function of Invariant Natural Killer T Cells Producing TH2- and TH17-Cytokines

Four distinct subsets of invariant natural killer T (NKT) cells are shown to differentiate in the thymus, then migrate to peripheral tissues where they retain their phenotypic and functional characteristics

Magnetic semiconductor quantum wells in high fields to 60 Tesla: Photoluminescence linewidth annealing at magnetization steps

Magnetic semiconductors offer a unique possibility for strongly tuning the intrinsic alloy disorder potential with applied magnetic field. We report the direct observation of a series of step-like reductions in the magnetic alloy disorder potential in single ZnSe/Zn(Cd,Mn)Se quantum wells between O and 60 Tesla. This disorder, measured through the linewidth of low temperature photoluminescence spectra drops abruptly at -19, 36, and 53 Tesla, in concert with observed magnetization steps. Conventional models of alloy disorder (developed for nonmagnetic semiconductors) reproduce the general shape of the data, but markedly underestimate the size of the linewidth reduction