Charlotte, NC, United States
Charlotte, NC, United States

Queens University of Charlotte is a private, co-educational, comprehensive university located in Charlotte, North Carolina, United States. The school has approximately 2,400 undergraduate and graduate students through the College of Arts and science, the McColl School of Business, the Wayland H. Cato, Jr. School of Education, the James L. Knight School of Communication, Hayworth College for Adult Studies and the Andrew Blair College of Health, which features the Presbyterian School of Nursing. Established in 1857, the university offers 39 undergraduate majors and 80 concentrations, and 19 graduate programs. Wikipedia.


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News Article | February 15, 2017
Site: physicsworld.com

An excited atom decaying in a vacuum experiences a force very similar to friction, according to calculations done by physicists in the UK. At first sight, the result appears to violate Einstein's equivalence principle. However, the researchers calculate that, in fact, relativity rides to its own rescue, and the mass lost from the atom as it decays to the ground state allows it to lose momentum without slowing down. Einstein's special theory of relativity famously says there is no such thing as absolute motion: the laws of physics are the same in all inertial frames of reference. Theoretical physicists Matthias Sonnleitner, Nils Trautmann and Stephen Barnett at the University of Glasgow noticed an apparent contradiction, however, when considering a textbook quantum-mechanics problem. An excited atom in a vacuum decays to a lower energy state, emitting a photon in a random direction. For simplicity, the problem is normally solved in the rest frame of the atom. In this frame, the magnitude of the photon's momentum is independent of its direction so, as a photon is equally likely to be emitted in any direction, the expectation values of the photon's momentum and the atom's consequent recoil momentum remain constant at zero. However, the trio also considered the problem in a frame in which the atom is moving: because of the Doppler effect, a photon emitted in the same direction of travel as the atom would be blue-shifted, having its frequency, and therefore its momentum, increased; whereas a photon emitted in the opposite direction would be red-shifted and have its momentum decreased. The atom would therefore experience a net force proportional to its momentum but in the opposite direction – effectively, it would experience friction from the vacuum. This appears to violate the principle of relativity because, if the atom's velocity changed, an observer could measure this change in velocity and use it to determine the absolute motion of the observer’s own frame of reference. Sonnleitner says the trio spent "weeks questioning their sanity". They later discovered an earlier paper, published on the arXiv pre-print server in 2012, in which Wei Guo of Queens University of Charlotte in North Carolina identified the problem but could not solve it. The Glasgow researchers eventually realized that, although they had not explicitly included relativity in their calculations, it had nevertheless sneaked in the back door: when an atom emits a photon and decays to a lower energy state, the classic equation E = mc2 shows that its mass must also decrease. Although the decrease is tiny, it is precisely sufficient to compensate for the decrease in momentum, allowing its velocity to stay constant. This only works when a small, often-neglected correction proposed in 1888 by the physicist Wilhelm Röntgen (who won the 1901 Nobel Prize for the discovery of X-rays) is included to accommodate the interaction between the moving atom's electric dipole and a magnetic field. In this latest research, the magnetic field is associated with quantum vacuum fluctuations. "[Guo’s 2012 paper] dropped the Röntgen term at some point," explains Sonnleitner. "The Röntgen term is necessary to get the correct change in momentum. Only then do you see that it's just due to a change in mass and not due to a change in velocity." Although the researchers considered the simplest possible situation, in which one atom in a vacuum decays by photon emission, the phenomenon is, in principle, applicable whenever an atom absorbs or emits a photon. "If this effect were larger," says Sonnleitner, "You would see its contribution whenever you tried to cool an atom, for instance." In practice, however, other influences are much larger in these cases, so the effect is not significant. He adds, "Experiments are getting so, so much better right now that it's really hard to say that something cannot be measured at all, but at least as far as I've seen this one is not feasible yet." "This is an interesting conceptual point," says theoretical physicist Peter Milonni of the University of Rochester in the US. "Maybe this work will lead the way to experiments to probe this conceptual difference between the change in momentum associated with translational motion and the change in momentum associated with the internal energy dynamics – these kinds of things are well known in nuclear physics. Whether it will lead to practical consequences in the theory of laser cooling and trapping, and new ways to trap atoms and so on: I don't think so, but I could be wrong." The research is described in Physical Review Letters.


News Article | February 23, 2017
Site: globenewswire.com

NEW YORK, Feb. 23, 2017 (GLOBE NEWSWIRE) -- Brenda S. Salyer, Registered Nurse at Carolinas HealthCare System has been selected to join the Nursing Board at the American Health Council. She will be sharing her knowledge and expertise on Nursing and Neurology. A photo accompanying this announcement is available at http://www.globenewswire.com/NewsRoom/AttachmentNg/c06e9f8d-d94b-4a6c-8e5c-8aaf982ab603 In the industry since 2012, Brenda offers valuable insight in her role as a Registered Nurse at Carolinas HealthCare System. As one of the leading healthcare organizations in the Southeast, Carolinas HealthCare System serves as a not-for-profit system comprised of operating hospitals, laboratories, nursing homes, pharmacies, freestanding emergency departments, outpatient, rehabilitation, and urgent care centers and medical practices at over nine hundred locations. As a Registered Nurse at Carolinas HealthCare System, Brenda’s day-to-day responsibilities include clinical treatment of patients suffering from stroke, traumatic brain injury, and seizure disorders. In 1992, Brenda earned a Masters of Business Administration from Rollins College; in 2011 Brenda earned a Bachelor of Science in Nursing from Queens University of Charlotte. To further develop her professional career, Brenda maintains affiliation with Sigma Theta Tau Nursing Honor Society and the American Association of Neuroscience Nurses. In her free time, she enjoys reading, fitness, and traveling. Considering the future, Brenda hopes for continual growth in research and exploring all the possible treatment options for a Registered Nurse today.


Guo W.,Queens University of Charlotte
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2011

Focusing of an incident light wave through a plano-convex spherical lens is discussed by calculating the light intensity distribution on the lens's optical axis after the incident wave is multiply scattered inside the lens. It is found that the size and location of the region into which the incident wave is focused are determined by two conditions. It is also found that it is possible for the wave to be focused into two such regions. © 2011 Optical Society of America.


Guo W.,Queens University of Charlotte
European Journal of Physics | Year: 2013

In this paper, wave propagation in one-dimensional few- and many-particle systems, all formed by interacting identical particles, is discussed for the purpose of explaining why wave propagation always has a finite speed in many-particle systems. After studying the equation of motion of each particle, it is demonstrated that such a finite speed is an observable speed realized after instantaneous wave propagation in few-particle systems is suppressed in many-particle systems by the large particle numbers in the latter systems. The expression of the speed is obtained and studied for its properties. © 2013 IOP Publishing Ltd.


Jones J.A.,Oregon State University | Perkins R.M.,Queens University of Charlotte
Water Resources Research | Year: 2010

We examined the effects of snow, event size, basin size, and forest harvest on floods using >1000 peak discharge events from 1953 to 2006 from three small (<1 km2), paired-watershed forest-harvest experiments and six large (60-600 km2) basins spanning the transient (400-800 m) and seasonal (>800 m) snow zones in the western Cascades of Oregon. Retrospectively classified rain-on-snow events delivered 75% more water to soils than rain events. Peak discharges of >10 year rain-on-snow events were almost twice as high as rain peaks in large basins but only slightly higher in small basins. Peak discharges of >1 year rain-on-snow events increased slightly (10%-20%) after logging in small basins, but small basin peaks do not account for the magnitudes of large basin rain-on-snow peak discharges during >1 year floods. In extreme floods, despite very high infiltration capacity, high soil porosity, and steep hillslope gradients, prolonged precipitation and synchronous snowmelt produce rapid, synchronized hydrograph responses to small variations in maximum precipitation intensity. At the large basin scale, forest harvest may increase the area of snowpack and simultaneous snowmelt, especially in elevation zones normally dominated by rain and transient snow, thereby increasing large basin peaks without producing very large percent increases in small basin peaks. Further work is needed to describe water flow paths in melting snowpack, snow cover and the area experiencing snowmelt, synoptic peak discharges, and routing of flood peaks through the stream network during extreme rain-on-snow floods. The evolving structure of the forest on the landscape is a potentially very important factor influencing extreme rain-on-snow floods. Copyright 2010 by the American Geophysical Union.


Guo W.,Queens University of Charlotte
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2012

In this work, scattering of an incident electric field from a moving atom is reexamined classically in two steps: the time-dependent current density created by the field inside the atom is first calculated under the electric-dipole approximation, and is then used to calculate the field scattered from the atom. Unlike the conventional framehopping method, the present method does not need to treat the Doppler effect as an effect separated from the scattering process, and it derives instead of simply uses the Doppler effect. © 2012 Optical Society of America.


Griffin L.,Queens University of Charlotte
Journal of Gay and Lesbian Mental Health | Year: 2011

Much has been written about the ethical perils associated with the psychotherapist's frequent role as evaluator and recommender (or gatekeeper) of medical treatment for transgender clients. Less information is available guiding therapists when they are called to perform as advocates for their clients. This article outlines several such situations. Potential ethical snags are discussed, and examples from the presenter's case experience are offered. © Taylor & Francis Group, LLC.


Guo W.,Queens University of Charlotte | Aktas Y.,University of North Carolina at Charlotte
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2012

In this work, the electric field emitted from a moving source, an electric point dipole, is analyzed for the purpose of illustrating the physics behind the Doppler effect. It is found that if the (translational) motion of the source is nonrelativistic, the Doppler effect is realized in two steps: the motion of the source first causes the dyadic Green function associated with the electric field to acquire an oscillation frequency in the far-field region of the source, and then the frequency leads to the Doppler effect. It is also demonstrated that the Doppler effect is observable only in the far-field region of the source. © 2012 Optical Society of America.


Guo W.,Queens University of Charlotte
Journal of Optics | Year: 2011

In this work, measurement in the near-field region of a sub-wavelength separation between two atoms is studied when the detector used to perform the measurement is modeled as another atom. Through an analysis of multiple scattering of an incident wave among the atoms, the back-action of the detector on the measurement is examined. It is found that, although the separation can never be measured exactly, the presence of the back-action makes the measurement more accurate. It is also found that the back-action enables the waves observed by the detector to avoid singularities that otherwise exist when the back-action is ignored. © 2011 IOP Publishing Ltd.


Guo W.,Queens University of Charlotte
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

Since diffraction is a scattering process in principle, light propagation through one aperture in a screen is discussed in the light-scattering theory. Through specific calculation, the expression of the electric field observed at an observation point is obtained and is used not only to explain why Kirchhoff's diffraction theory is a good approximation when the screen is both opaque and sufficiently thin but also to demonstrate that the mathematical and physical problems faced by Kirchhoff's theory are avoided in the light-scattering theory. © 2010 Optical Society of America.

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