2,551 research outputs found
Undergraduate Diversity Scholar Program: A Proactive Approach to Creating an Inclusive and Multicultural Workforce
The University of Kentucky (UK) Libraries approved a statement in September 2013 confirming its commitment to cultivating and encouraging diversity and inclusivity in its personnel policies and in its collections, programs, and services. The library subsequently developed an Undergraduate Diversity Scholar Program to provide two students with a paid internship in the 2014/15 academic year. UK undergraduates interested in diversity issues were encouraged to apply. Applicants were evaluated based on their work experience, volunteer or service activities, recommendations from two referees, and an essay about their belief in the benefits of a diverse society. The successful candidates started the inaugural Program in Fall 2014 and developed and/or led activities and research that promoted the benefits of inclusivity and multicultural awareness in the UK community. They also explored career options in academic librarianship through working in several different library units. Additionally, they received mentoring on building their résumés and preparing for future employment
Confinement effects in a guided-wave interferometer with millimeter-scale arm separation
Guided-wave atom interferometers measure interference effects using atoms
held in a confining potential. In one common implementation, the confinement is
primarily two-dimensional, and the atoms move along the nearly free dimension
under the influence of an off-resonant standing wave laser beam. In this
configuration, residual confinement along the nominally free axis can introduce
a phase gradient to the atoms that limits the arm separation of the
interferometer. We experimentally investigate this effect in detail, and show
that it can be alleviated by having the atoms undergo a more symmetric motion
in the guide. This can be achieved by either using additional laser pulses or
by allowing the atoms to freely oscillate in the potential. Using these
techniques, we demonstrate interferometer measurement times up to 72 ms and arm
separations up to 0.42 mm with a well controlled phase, or times of 0.91 s and
separations of 1.7 mm with an uncontrolled phase.Comment: 14 pages, 6 figure
Stabilizing an Attractive Bose-Einstein Condensate by Driving a Surface Collective Mode
Bose-Einstein condensates of Li have been limited in number due to
attractive interatomic interactions. Beyond this number, the condensate
undergoes collective collapse. We study theoretically the effect of driving
low-lying collective modes of the condensate by a weak asymmetric sinusoidally
time-dependent field. We find that driving the radial breathing mode further
destabilizes the condensate, while excitation of the quadrupolar surface mode
causes the condensate to become more stable by imparting quasi-angular momentum
to it. We show that a significantly larger number of atoms may occupy the
condensate, which can then be sustained almost indefinitely. All effects are
predicted to be clearly visible in experiments and efforts are under way for
their experimental realization.Comment: 4 ReVTeX pages + 2 postscript figure
A Time-Orbiting Potential Trap for Bose-Einstein Condensate Interferometry
We describe a novel atom trap for Bose-Einstein condensates of 87Rb to be
used in atom interferometry experiments. The trap is based on a time-orbiting
potential waveguide. It supports the atoms against gravity while providing weak
confinement to minimize interaction effects. We observe harmonic oscillation
frequencies omega_x, omega_y, omega_z as low as 2 pi times (6.0,1.2,3.3) Hz. Up
to 2 times 10^4 condensate atoms have been loaded into the trap, at estimated
temperatures as low as 850 pK. We anticipate that interferometer measurement
times of 1 s or more should be achievable in this device.Comment: 9 pages, 3 figure
A Bose-Einstein condensate interferometer with macroscopic arm separation
A Michelson interferometer using Bose-Einstein condensates is demonstrated
with coherence times of up to 44 ms and arm separations up to 0.18 mm. This arm
separation is larger than that observed for any previous atom interferometer.
The device uses atoms weakly confined in a magnetic guide and the atomic motion
is controlled using Bragg interactions with an off-resonant standing wave laser
beam.Comment: 4 pages, 3 figure
Evidence-based medicine and values-based medicine : partners in clinical education as well as in clinical practice
The best clinical decisions are based on both evidence and values in what is known as the ‘twofeet principle’. Anecdotally, educationalists find teaching clinicians to become more evidence based is relatively simple in comparison to encouraging them to become more values based. One reason is likely to be the importance of values awareness. As valuesbased practice is premised on a mutual respect for the diversity of values, clinicians need to develop the skills to ascertain patient values and to get in touch with their own beliefs and preferences in order to understand those at play in any consultation. Only then can shared decision-making processes take place within a shared framework of values. In a research article published in BMC Medicine, AltamiranoBustamante and colleagues highlight difficulties that clinicians face in getting in touch with their own values. Despite finding that healthcare personnel’s core values were honesty and respect, autonomy was initially low ranked by participants. One significant aspect of this work is that this group has demonstrated that the extent to which clinicians value ‘autonomy’ and ‘openness to change’ can both be positively influenced by well designed education
The Distribution of Dark Matter in a Ringed Galaxy
Outer rings are located at the greatest distance from the galaxy center of
any feature resonant with a bar. Because of their large scale, their morphology
is sensitive to the distribution of the dark matter in the galaxy. We introduce
here how study of these rings can constrain the mass-to-light ratio of the bar,
and so the percentage of dark matter in the center of these galaxies. We
compare periodic orbits integrated in the ringed galaxy NGC 6782 near the outer
Lindblad resonance to the shape of the outer ring. The non-axisymmetric
component of the potential resulting from the bar is derived from a
near-infrared image of the galaxy. The axisymmetric component is derived
assuming a flat rotation curve. We find that the pinched non-self-intersecting
periodic orbits are more elongated for higher bar mass-to-light ratios and
faster bars. The inferred mass-to-light ratio of the bar depends on the assumed
inclination of the galaxy. With an assumed galaxy inclination of i=41 degrees,
for the orbits to be consistent with the observed ring morphology the
mass-to-light ratio of the bar must be high, greater than 70% of a maximal disk
value. For i=45 degrees, the mass-to-light ratio of the bar is of
the maximal disk value. Since the velocity field of these rings can be used to
constrain the galaxy inclination as well as which periodic orbit is represented
in the ring, further study will yield tighter constraints on the mass-to-light
ratio of the bar. If a near maximal disk value for the bar is required, then
either there would be little dark matter within the bar, or the dark matter
contained in the disk of the galaxy would be non-axisymmetric and would rotate
with the bar.Comment: AAS Latex + jpg Figures, Accepted for publication in Ap
Measurement of the ac Stark shift with a guided matter-wave interferometer
We demonstrate the effectiveness of a guided-wave Bose-Einstein condensate
interferometer for practical measurements. Taking advantage of the large arm
separations obtainable in our interferometer, the energy levels of the 87Rb
atoms in one arm of the interferometer are shifted by a calibrated laser beam.
The resulting phase shifts are used to determine the ac polarizability at a
range of frequencies near and at the atomic resonance. The measured values are
in good agreement with theoretical expectations. However, we observe a
broadening of the transition near the resonance, an indication of collective
light scattering effects. This nonlinearity may prove useful for the production
and control of squeezed quantum states.Comment: 5 pages, three figure
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