Study of an attitude control system for the astronaut maneuvering unit final report, dec. 1963 - jul. 1964

Attitude control system for astronaut maneuvering unit

Validating the Assessing Student Competence and Knowledge of Social Determinants of Health (ASCK-SDH) Instrument

The impact of the social determinants of health (SDH) on health outcomes is receiving increased attention. Health profession students need to learn about SDH; however, there are no validated tools to measure student competence in assessing SDH. There is a need for a brief, valid instrument to measure student competency and knowledge of SDH. This study is a secondary analysis of data collected pre (N=394) and post (N=387) for an interprofessional learning event. We utilized principal component analysis (PCA) with varimax rotation to determine the internal structure of the tool. The original measure consisted of 11 items; the analysis resulted in two factors. Based on the two factors it was determined the three items from Factor 2 were not contributing to the scale; therefore, they were removed. The final measure, Assessing Student Competence & Knowledge of Social Determinants of Health (ASCK-SDH), consists of eight items rated on a 4-point Likert scale. The measure indicated high internal consistency at pre (Cronbach’s α= 0.81) and post (Cronbach’s α=0.89) tests. The ASCK-SDH tool provides a valid instrument to measure student competence and knowledge about SDH and can be used to assess learning

Validating the Assessing Student Competence and Knowledge of Social Determinants of Health (ASCK-SDH) Instrument

The impact of the social determinants of health (SDH) on health outcomes is receiving increased attention. Health profession students need to learn about SDH; however, there are no validated tools to measure student competence in assessing SDH. There is a need for a brief, valid instrument to measure student competency and knowledge of SDH. This study is a secondary analysis of data collected pre (N=394) and post (N=387) for an interprofessional learning event. We utilized principal component analysis (PCA) with varimax rotation to determine the internal structure of the tool. The original measure consisted of 11 items; the analysis resulted in two factors. Based on the two factors it was determined the three items from Factor 2 were not contributing to the scale; therefore, they were removed. The final measure, Assessing Student Competence & Knowledge of Social Determinants of Health (ASCK-SDH), consists of eight items rated on a 4-point Likert scale. The measure indicated high internal consistency at pre (Cronbach’s α= 0.81) and post (Cronbach’s α=0.89) tests. The ASCK-SDH tool provides a valid instrument to measure student competence and knowledge about SDH and can be used to assess learning

Temperature dependence of the interlayer magnetoresistance of quasi-one-dimensional Fermi liquids at the magic angles

The interlayer magnetoresistance of a quasi-one-dimensional Fermi liquid is considered for the case of a magnetic field that is rotated within the plane perpendicular to the most-conducting direction. Within semi-classical transport theory dips in the magnetoresistance occur at integer amgic angles only when the electronic dispersion parallel to the chains is nonlinear. If the field direction is fixed at one of the magic angles and the temperature is varied the resulting variation of the scattering rate can lead to a non-monotonic variation of the interlayer magnetoresistance with temperature. Although the model considered here gives a good description of some of the properties of the Bechgaard salts, (TMTSF)2PF6 for pressures less than 8kbar and (TMTSF)2ClO4 it gives a poor description of their properties when the field is parallel to the layers and of the intralayer transport.Comment: 10pages, RevTeX + epsf, 3 figure

Resonance absolute quantum reflection at selected energies

The possibility of the resonance reflection (100 % at maximum) is revealed. The corresponding exactly solvable models with the controllable numbers of resonances, their positions and widths are presented.Comment: 5 pages, 2 figure

Saturn's Seasonal Atmosphere at Northern Summer Solstice

The incredible longevity of Cassini's orbital mission at Saturn has provided the most comprehensive exploration of a seasonal giant planet to date. This review explores Saturn's changing global temperatures, composition, and aerosol properties between northern spring and summer solstice (2015-2017), extending our previous review of Cassini's remote sensing investigations (2004-14, Fletcher et al., 2018) to the grand finale. The result is an unprecedented record of Saturn's climate that spans almost half a Saturnian year, which can be used to test the seasonal predictions of radiative climate models, neutral and ion photochemistry models, and atmospheric circulation models. Hemispheric asymmetries in tropospheric and stratospheric temperatures were observed to reverse from northern winter to northern summer; spatial distributions of hydrocarbons and para-hydrogen shifted in response to atmospheric dynamics (e.g., seasonally-reversing Hadley cells, polar stratospheric vortex formation, equatorial stratospheric oscillations, and inter-hemispheric transport); and upper tropospheric and stratospheric aerosols exhibited changes in optical thickness that modulated Saturn's visible colours (from blue hues to a golden appearance in the north near solstice), reflectivity, and near-infrared emission. Numerical simulations of radiative balance and photochemistry do a good job in reproducing the observed seasonal change and phase lags, but discrepancies between models and observations still persist, indicating a crucial role for atmospheric dynamics and the need to couple chemical and radiative schemes to the next generation of circulation models. With Cassini's demise, an extended study of Saturn's seasons, from northern summer to autumn, will require the capabilities of ground- and space-based observatories, as we eagerly await the next orbital explorer at Saturn.Comment: 24 pages, 18 figures, submitted for publication by Cambridge University Press as part of a multi-volume work edited by Kevin Baines, Michael Flasar, Norbert Krupp, and Thomas Stallard, entitled "Cassini at Saturn: The Grand Finale." The copy of the Chapter, as displayed on this website, is a draft, pre-publication copy onl

Sensitivity of Pseudomonas Species Expressing Extended Spectrum Beta Lactamase to Different Solvent Fractions of Milletia Aboensis

The presence of Extended Spectrum Beta Lactamase (ESBL) producing organisms in abattoirs, a non-hospital community was investigated. A total of ten (10) isolates of Pseudomonas species out of twenty-six bacteria isolates expressing ESBL was obtained. The anti-pseudomonal activities of various solvent fractions of Milletia aboensis against the ESBL positive isolates of Pseudomonas species showed varying sensitivity. These results have suggested that Milletia aboensis possess potent anti-pseudomonal agents that could be used to treat infections due to Pseudomonas species expressing ESBL. These anti-pseudomonal metabolites are located in the ethanol, chloroform and methanol fractions but are absent in the ethyl acetate fractions. Keywords: Extended Spectrum Beta Lactamase, Milletia aboensis, Pseudomonas specie

Magnetic Field Limitations on Advection Dominated Flows

Recent papers discussing advection dominated accretion flows (ADAF) as a solution for astrophysical accretion problems should be treated with some caution because of their uncertain physical basis. The suggestions underlying ADAF involve ignoring the magnetic field reconnection in heating of the plasma flow, assuming electron heating due only to binary Coulomb collisions with ions. Here, we analyze the physical processes in optically thin accretion flows at low accretion rates including the influence of an equipartition turbulent magnetic field. For these conditions there is continuous destruction of magnetic flux by reconnection. The reconnection is expected to significantly heat the electrons which can efficiently emit magnetobremstrahlung radiation. Because of this electron emission, the radiative efficiency of the ADAF is not small. We suggest that the small luminosities of nearby galactic black holes is due to outflows rather than ADAF accretion.Comment: 7 pages, 3 figures, Submitted to Ap