Photometric and kinematic studies of open star clusters. III. NGC 4103, NGC 5281, and NGC 4755

We present CCD photometry and proper motion studies of the three open star clusters NGC 4103, NGC 5281, and NGC 4755 (kappa Cru). By fitting isochrones to the colour magnitude diagrams, we found that all three objects are young open star clusters with ages of at most t=45 Myr. They are located at distances from approx. 1600 pc to 2200 pc, derived from distance moduli (m-M)_0 ranging from 11 mag to 12 mag. We combined membership determinations based on proper motions and statistical field star subtraction to derive the initial mass function (IMF) of the clusters. The shape of the IMFs could be represented by power laws with exponents of Gamma=-1.46 +/- 0.22 for NGC 4103, Gamma=-1.60 +/- 0.50 for NGC 5281, and Gamma=-1.68 +/- 0.14 for NGC 4755, when - as a reference - Salpeter's (1955) value would be Gamma=-1.35. These results agree well with other IMF studies of open star clusters.Comment: 16 pages, 14 figures, accepted for publication in Astronomy & Astrophysic

Lateral Violence Response Training for Nursing Students

Title from PDF of title page, viewed on July 6, 2015Dissertation advisor: Peggy Ward-SmithVitaIncludes bibliographic references (pages 83-91)Thesis (Ph.D.)--School of Nursing and Health Studies. University of Missouri--Kansas City, 2015Lateral violence among nurses is a pervasive problem contributing to deleterious consequences for targets, work environments, patient outcomes, and the nursing profession. Newly licensed nurses are at a disadvantage to respond effectively to lateral violence and may be more likely to be targeted. Thus, response training prior to entering the nursing workforce may increase their ability to manage lateral violence they encounter as newly licensed nurses. There is a paucity of interventional research aimed at educating nurses on effective and appropriate responses to lateral violence and no studies involving nursing students. This study examines the effect of an educational intervention to increase nursing students’ self-efficacy in responding to lateral violence. Cognitive Behavioral Therapy, based on Social Cognitive Theory, was used to guide the format of the intervention and development of the measurement instrument. A time-series, randomized, cluster design with intervention and control groups, was used to increase rigor over existing studies. Statistically significant increase in participant-reported self-efficacy among the intervention group was determined using paired t-tests. Follow-up data indicate potential for the long-term benefits of this intervention on self-efficacy in responding to lateral violence. Clinical significance was also demonstrated by overall increases in all quartiles among the intervention group. These results indicate potential for use among future nursing students. Future research should include longitudinal follow-up to determine the long term effects of this intervention, testing among nursing students at different types of institutions, and refinement of the measurement instrument.Introduction -- Review of the literature and background -- Methods -- Data analysis -- Conclusions -- Appendix A. Permission Letter for use of SADBS-R Appendix B. Instrument - SADBS-R -- Appendix C. Consent Form – Intervention Site -- Appendix D. Consent Form – Attention-Control Site -- Appendix E. Intervention – Lateral Violence Response Training -- Appendix F. Attention Control Group Activit

Critical velocity for superfluid flow across the BEC-BCS crossover

Critical velocities have been observed in an ultracold superfluid Fermi gas throughout the BEC-BCS crossover. A pronounced peak of the critical velocity at unitarity demonstrates that superfluidity is most robust for resonant atomic interactions. Critical velocities were determined from the abrupt onset of dissipation when the velocity of a moving one dimensional optical lattice was varied. The dependence of the critical velocity on lattice depth and on the inhomogeneous density profile was studied

Auto Tracking Antenna Platform

The present invention is an auto tracking antenna platform upon which multiple antenna elements can be mounted to track a common moving object. The antenna tracking platform generally comprises a bottom pedestal enclosing a rotary azimuth actuator for controlled-rotary motion about the single vertical (z) axis, and an upper multi-tier framework housing a horizontal antenna-mounting beam pivotally supported for rotation about a horizontal (x) axis, and a drive assembly for direct-drive rotation of the antenna-mounting bar. Antenna elements are mounted along the horizontal mounting bar and the feeds routed through the azimuth actuator. This enables the use of fiber optic rotary joints or slip rings to pass data and video, instead of RF (waveguide) rotary joints which are required to pass high power RF signals

Correlations and Pair Formation in a Repulsively Interacting Fermi Gas

A degenerate Fermi gas is rapidly quenched into the regime of strong effective repulsion near a Feshbach resonance. The spin fluctuations are monitored using speckle imaging and, contrary to several theoretical predictions, the samples remain in the paramagnetic phase for arbitrarily large scattering length. Over a wide range of interaction strengths a rapid decay into bound pairs is observed over times on the order of 10\hbar/E_F, preventing the study of equilibrium phases of strongly repulsive fermions. Our work suggests that a Fermi gas with strong short-range repulsive interactions does not undergo a ferromagnetic phase transition

Quantum reflection of atoms from a solid surface at normal incidence

We observed quantum reflection of ultracold atoms from the attractive potential of a solid surface. Extremely dilute Bose-Einstein condensates of ^{23}Na, with peak density 10^{11}-10^{12}atoms/cm^3, confined in a weak gravito-magnetic trap were normally incident on a silicon surface. Reflection probabilities of up to 20 % were observed for incident velocities of 1-8 mm/s. The velocity dependence agrees qualitatively with the prediction for quantum reflection from the attractive Casimir-Polder potential. Atoms confined in a harmonic trap divided in half by a solid surface exhibited extended lifetime due to quantum reflection from the surface, implying a reflection probability above 50 %.Comment: To appear in Phys. Rev. Lett. (December 2004)5 pages, 4 figure

Speckle Imaging of Spin Fluctuations in a Strongly Interacting Fermi Gas

Spin fluctuations and density fluctuations are studied for a two-component gas of strongly interacting fermions along the BEC-BCS crossover. This is done by in-situ imaging of dispersive speckle patterns. Compressibility and magnetic susceptibility are determined from the measured fluctuations. This new sensitive method easily resolves a tenfold suppression of spin fluctuations below shot noise due to pairing, and can be applied to novel magnetic phases in optical lattices

Progress in the development of an electronic nose using arrays of chemically sensitive carbon black-polymer resistors

Response data were collected for a carbon black-polymer composite electronic nose array during exposure to homologous series of alkanes and alcohols. At a fixed partial pressure of odorant in the vapor phase, the mean response intensity of the electronic nose signals varied significantly for members of each series of odorants. However, the mean response intensity of the electronic nose detectors, and the response intensity of the most strongly-driven set of electronic nose detectors, was essentially constant for members of a chemically homologous odorant series when the concentration of each odorant in the gas phase was maintained at a constant fraction of the odorant's vapor pressure. Because the thermodynamic activity of an odorant at equilibrium in a sorbent phase is equal to the partial pressure of the odorant in the gas phase divided by the vapor pressure of the odorant, and because the activity coefficients are similar within these homologous series of odorants for sorption of the vapors into specific polymer films, the data imply that the trends in detector response can be understood based on the thermodynamic tendency to establish a relatively constant concentration of sorbed odorant into each of the polymeric films of the electronic nose at a constant fraction of the odorant's vapor pressure. This phenomenon provides a natural mechanism for enhanced sensitivity to low vapor pressure compounds, like TNT, in the presence of high vapor pressure analytes, such as diesel fuel. In a related study to evaluate the target recognition properties of the electronic nose, a statistical metric based on the magnitudes and standard deviations along Euclidean projections of clustered array response data, was utilized to facilitate an evaluation of the performance of detector arrays in various vapor classification tasks. This approach allowed quantification of the ability of a fourteen-element array of carbon black-insulating polymer composite chemiresistors to distinguish between members of a set of nineteen solvent vapors, some of which vary widely in chemical properties (e.g. methanol and benzene) and others of which are very similar (e.g. n-pentane and n-heptane). The data also facilitated evaluation of questions such as array performance as a function of the number of detectors in the system

Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10,000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.Comment: minor edit: fixed technical problem with arxiv's processing of .eps figur