2,678 research outputs found
An Englishman Who Collaborated with the Spanish Armada
Paper by Dr. John E. Paris
SU(N) Fermions in a One-Dimensional Harmonic Trap
We conduct a theoretical study of SU(N) fermions confined by a
one-dimensional harmonic potential. Firstly, we introduce a new numerical
approach for solving the trapped interacting few-body problem, by which one may
obtain accurate energy spectra across the full range of interaction strengths.
In the strong-coupling limit, we map the SU(N) Hamiltonian to a spin-chain
model. We then show that an existing, extremely accurate ansatz - derived for a
Heisenberg SU(2) spin chain - is extendable to these N-component systems.
Lastly, we consider balanced SU(N) Fermi gases that have an equal number of
particles in each spin state for N=2, 3, 4. In the weak- and strong-coupling
regimes, we find that the ground-state energies rapidly converge to their
expected values in the thermodynamic limit with increasing atom number. This
suggests that the many-body energetics of N-component fermions may be
accurately inferred from the corresponding few-body systems of N
distinguishable particles.Comment: 15 pages, 6 figure
Dermatology is a specialty; dermatology is not a subspecialty.
Specialization began in American medicine about the time of the War Between the States. Several factors spurred the direction of practitioners away from being the so-called “complete physicians. Most important were the advances in instrumentation made by the 1860’s, which allowed ophthalmology and otolaryngology to develop into distinct divisions of allopathic medicine; sometimes, they even joined together, viz eye, ear, nose, and throat specialist. Dermatology, too, became one of the early specialties for a myriad of reasons ranging from the obvious – visual inspection - to the mundane, viz. default – syphilis was too ugly and complicated for every physician to diagnose and treat. (1)
When American medical education began to expand in the early to mid-nineteenth century, the surgeons and even the obstetricians (2) often gave the lectures on skin diseases. After all, to paraphrase an early discourse at Jefferson Medical College by a surgeon – all skin disease can be divided into those treated by sulfur ointment and those not treated by sulfur ointment. (3)
Dermatology in the United States can boast of having the first dermatology society in the world and one of the first specialty societies – New York Dermatological Society – founded in 1869. The American Journal of Dermatology and Syphilography (1870-1874) was among the first of the specialty publications, not only in the United States but worldwide. (4
Three-body analytical potential for interacting helium atoms
Large basis set ab initio calculations have been carried out for a dense grid of points on the He, potential energy surface. Three-body contributions were extracted at every point, and a number of concise functional representations for the three-body potential surface were then examined. Three-body multipolar dispersion terms and other radial and angular terms were used in the representations, and an assessment of relative importance of the different terms is presented. Combined with a two-body He-He potential, the results of this work should offer a high quality interaction potential for simulations of aggregated helium
Pairwise and many-body contributions to interaction potentials in He(n) clusters
High level ab initio calculations have been carried out to assess the pairwise additivity of potentials in the attractive or well regions of the potential surfaces of clusters of helium atoms. A large basis set was employed and calculations were done at the Brueckner orbital coupled cluster level. Differences between calculated potentials for several interacting atoms and the corresponding summed pair potentials reveal the three‐body and certain higher order contributions to the interaction strengths. Attraction between rare gas atoms develops from dispersion, and so helium clusters provide the most workable systems for analyzing nonadditivity of dispersion. The results indicate that the many‐body or nonpairwise contributions tend to be less than a few percent of the attractive interaction across regions around the minima of the potential energy surfaces of small clusters. Dipole–dipole–dipole dispersion and dipole–dipole–quadrupole dispersion are noticeable parts of the small three‐body terms
What is wrong with 'being a pill-taker'? The special case of statins.
In an interview study of decision-making about statins, many participants said they took pills regularly, yet described themselves as 'not really pill-takers'. This paper explores this paradox and its implications. The practice of pill-taking itself can constitute a challenge to the presentation of moral adequacy, beyond the potential for rendering stigmatised illnesses visible. Meeting this challenge involves a complex process of calibrating often-conflicting moral imperatives: to be concerned, but not too concerned, over one's health; to be informed, but not over-informed; and deferential but not over-deferential to medical expertise. This calibration reflects a broader tension between rival tropes: embracing medical progress and resisting medicalisation. Participants who take statins present them as unquestionably necessary; 'needing' pills, as opposed to choosing to take them, serves as a defence against the devalued identity of being a pill-taker. However, needing to take statins offers an additional threat to identity, because taking statins is widely perceived to be an alternative strategy to 'choosing a healthy lifestyle'. This perception underpins a responsibilising health promotion discourse that shapes and complicates the work participants do to avoid presenting themselves as 'pill-takers'. The salience of this discourse should be acknowledged where discussions of medicalisation use statins as an example
Income Poverty and Material Hardship among U.S. Women with Disabilities
This study analyzes the 2002 wave of the National Survey of America’s Families to describe income poverty and material hardship among women with and without disabilities in the United States. Results suggest that women with disabilities experience such hardships as food insecurity, housing instability, inadequate health care, and loss of phone service at rates that are higher than those among nondisabled women. Rates of hardship remain higher even after adjusting for a host of individual characteristics, including marital status, age, race, and education. Although hardship declines as incomes rise for all women, those with disabilities show worse outcomes at every income level and experience substantial levels of hardship well into the middle and upper income ranges. The federal poverty level does not accurately capture women’s experiences of material hardship, and these discrepancies are considerably worse among women with disabilities
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