51 research outputs found
Deflection of Slow Light by Magneto-Optically Controlled Atomic Media
We present a semi-classical theory for light deflection by a coherent
-type three-level atomic medium in an inhomogeneous magnetic field or
an inhomogeneous control laser. When the atomic energy levels (or the Rabi
coupling by the control laser) are position-dependent due to the Zeeman effect
by the inhomogeneous magnetic field (or the inhomogeneity of the control field
profile), the spatial dependence of the refraction index of the atomic medium
will result in an observable deflection of slow signal light when the
electromagnetically induced transparency happens to avoid medium absorption.
Our theoretical approach based on Fermat's principle in geometrical optics not
only provides a consistent explanation for the most recent experiment in a
straightforward way, but also predicts the new effects for the slow signal
light deflection by the atomic media in an inhomogeneous off-resonant control
laser field.Comment: 4 pages, 3 figure
Bacillus Coagulans GBI-30 (BC30) improves indices of Clostridium difficile-Induced colitis in mice
<p>Abstract</p> <p>Background</p> <p>Probiotics have beneficial effects in rodent models of <it>Clostridium difficile </it>(<it>C. diffiicle</it>)-induced colitis. The spore forming probiotic strain <it>Bacillus Coagulans </it>GBI-30, 6086 (BC30) has demonstrated anti-inflammatory and immune-modulating effects <it>in vitro</it>. Our goal was to determine if BC30 improved <it>C. difficile</it>-induced colitis in mice. Starting on study day 0, female C57BL/6 mice were dosed by oro-gastric gavage for 15 days with vehicle (saline) or BC30 (2 à 10<sup>9 </sup>CFU per day). Mice in the <it>C. difficile </it>groups received an antibiotic mixture (study days 5 to 8 in the drinking water), and clindamycin (10 mg/kg, i.p., on study day 10). The <it>C. difficile </it>strain VPI 10463 was given by gavage at 10<sup>4 </sup>CFU to induce colitis on day 11. On day 16, stools and colons were collected for further analyses.</p> <p>Results</p> <p>All mice treated with BC30 survived on study day 13, while two mice treated with vehicle did not survive. On day 12, a significant difference (p = 0.0002) in the percentage of mice with normal stools (66.7%) was found in the BC30/<it>C. difficile </it>group, as compared to the vehicle/<it>C. diffcile </it>group (13.0%). On study day 16, 23.8% of mice treated with BC30 had normal stools, while this value was 0% with vehicle treatment (p value = 0.0187). On this day, the stool consistency score for the BC30/<it>C. difficile </it>group (1.1 ± 0.2) was significantly lower (p < 0.05) than for the vehicle/<it>C. difficile </it>cohort (1.9 ± 0.2). BC30 modestly attenuated the colonic pathology (crypt damage, edema, leukocyte influx) that was present following <it>C. difficile infection</it>. Colonic MIP-2 chemokine contents (pg/2 cm colon) were: 10.2 ± 0.5 (vehicle/no <it>C. difficile</it>), 24.6 ± 9.5 (vehicle/<it>C. difficile</it>) and 16.3 ± 4.3 (BC30/<it>C. difficle</it>).</p> <p>Conclusion</p> <p>The probiotic BC30 improved some parameters of <it>C. difficile</it>-induced colitis in mice. BC30 prolonged the survival of <it>C. diffiicle </it>infected mice. Particularly, this probiotic improved the stool consistency of mice, in this infectious colitis model.</p
The Synthesis Telescope at the Dominion Radio Astrophysical Observatory
We describe an aperture synthesis radio telescope optimized for studies of
the Galactic interstellar medium (ISM), providing the ability to image extended
structures with high angular resolution over wide fields. The telescope
produces images of atomic hydrogen emission using the 21-cm HI spectral line,
and, simultaneously, continuum emission in two bands centred at 1420 MHz and
408 MHz, including linearly polarized emission at 1420 MHz, with synthesized
beams of 1 degree and 3.4 degrees at the respective frequencies.Comment: Accepted for publication by Astronomy and Astrophysics, Supplement
Serie
From Anderson to anomalous localization in cold atomic gases with effective spin-orbit coupling
We study the dynamics of a one-dimensional spin-orbit coupled Schrodinger
particle with two internal components moving in a random potential. We show
that this model can be implemented by the interaction of cold atoms with
external lasers and additional Zeeman and Stark shifts. By direct numerical
simulations a crossover from an exponential Anderson-type localization to an
anomalous power-law behavior of the intensity correlation is found when the
spin-orbit coupling becomes large. The power-law behavior is connected to a
Dyson singularity in the density of states emerging at zero energy when the
system approaches the quasi-relativistic limit of the random mass Dirac model.
We discuss conditions under which the crossover is observable in an experiment
with ultracold atoms and construct explicitly the zero-energy state, thus
proving its existence under proper conditions.Comment: 4 pages and 4 figure
Development and implementation of an herbal and natural product elective in undergraduate medical education
<p>Abstract</p> <p>Background</p> <p>Medical students have consistently expressed interest in learning about alternative healing modalities, especially herbal and natural products. To fill this void in medical education at our institution, a novel elective was developed and implemented for fourth year medical students. This herbal/natural product course uses guest lecturers, classroom presentations, and active learning mechanisms that include experiential rotations, case-based learning, and team-based learning to increase student knowledge of herbal/natural product safety and efficacy.</p> <p>Methods</p> <p>Knowledge outcomes were evaluated via administration of a pre- and post-course test (paired student <it>t</it>-test). End-of-course evaluations (Likert-type questions and narrative responses) were used to assess student opinion of knowledge and skills imparted by the elective and overall course content (mean, standard deviation).</p> <p>Results</p> <p>Over three academic years, 23 students have enrolled in this elective. More than 60% of participants have been female and nearly half of the students (43%) have pursued residencies in primary care. Completion of the course significantly increased student knowledge of common herbal/natural product mechanisms, uses, adverse effects, and drug-interactions as determined by a pre- and post-course knowledge assessment (45%â±â10% versus 78%â±â6%; pâ<â0.0001). The course was highly rated by enrollees (overall course quality, 4.6 of 5.0â±â0.48) who appreciated the variety of activities to which they were exposed and the open classroom discussions that resulted. While students tended to view some alternative medical systems with skepticism, they still believed it was valuable to learn what these modalities encompass.</p> <p>Conclusions</p> <p>Development and implementation of a herbal/natural product elective that engages undergraduate medical students through active learning mechanisms and critical analysis of the literature has proven effective in increasing knowledge outcomes and is deemed to be a valuable curricular addition by student participants. In the future, it will be of interest to explore mechanisms for expanding the course to reach a larger number of students within the time, financial, and logistical constraints that currently exist.</p
Topological Qubits with Majorana Fermions in Trapped Ions
We propose a method of encoding a topologically-protected qubit using
Majorana fermions in a trapped-ion chain. This qubit is protected against major
sources of decoherence, while local operations and measurements can be
realized. Furthermore, we show that an efficient quantum interface and memory
for arbitrary multiqubit photonic states can be built, encoding them into a set
of entangled Majorana-fermion qubits inside cavities.Comment: 9 pages, 2 figure
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