Counting physicians in specialties: By what they do or how they train?

The number of actively practicing physicians in the United States is not precisely known, nor do we know the total number of physicians required to meet population needs. The possible gap between these two numbers is a controversial issue, especially for primary care physicians. Primary care physicians can be counted in more than one way, either by their "area of practice" (in other words, what they do) or by the specialty in which they train. Regulatory agencies and other health organizations see the area of practice as more relevant to understanding physician supply. In North Carolina, the counts of primary care physicians were historically based on specialty of training. In 2010, the way physicians were counted was changed from definition by specialty of training to definition by area of practice, which resulted in an apparent drop in the number of primary care physicians by more than 16% in a single year. When terms such as "hospitalist," "urgent care," "student health," and "integrative medicine" were added to describe additional practice areas of physicians, most of the loss was accounted for. Researchers, regulators and policy makers need to be aware of the effects of a shift in how physicians are counted and assigned to specialties to understand the extent of pending shortages

Sub-millimeter Tests of the Gravitational Inverse-square Law

Motivated by a variety of theories that predict new effects, we tested the gravitational 1/r^2 law at separations between 10.77 mm and 137 microns using two different 10-fold azimuthally symmetric torsion pendulums and rotating 10-fold symmetric attractors. Our work improves upon other experiments by up to a factor of about 100. We found no deviation from Newtonian physics at the 95% confidence level and interpret these results as constraints on extensions of the Standard Model that predict Yukawa or power-law forces. We set a constraint on the largest single extra dimension (assuming toroidal compactification and that one extra dimension is significantly larger than all the others) of R <= 160 microns, and on two equal-sized large extra dimensions of R <= 130 microns. Yukawa interactions with |alpha| >= 1 are ruled out at 95% confidence for lambda >= 197 microns. Extra-dimensions scenarios stabilized by radions are restricted to unification masses M >= 3.0 TeV/c^2, regardless of the number of large extra dimensions. We also provide new constraints on power-law potentials V(r)\propto r^{-k} with k between 2 and 5 and on the gamma_5 couplings of pseudoscalars with m <= 10 meV/c^2.Comment: 34 pages, 38 figure

Seasonal patterns of shell flux, delta O-18 and delta C-13 of small and large N. pachyderma (s) and G. bulloides in the subpolar North Atlantic

<p>Past water column stratification can be assessed through comparison of the delta O-18 of different planktonic foraminiferal species. The underlying assumption is that different species form their shells simultaneously, but at different depths in the water column. We evaluate this assumption using a sediment trap time-series of Neogloboquadrina pachyderma (s) and Globigerina bulloides from the NW North Atlantic. We determined fluxes, delta O-18 and delta C-13 of shells from two size fractions to assess size-related effects on shell chemistry and to better constrain the underlying causes of isotopic differences between foraminifera in deep-sea sediments. Our data indicate that in the subpolar North Atlantic differences in the seasonality of the shell flux, and not in depth habitat or test size, determine the interspecies Delta delta O-18. N. pachyderma (s) preferentially forms from early spring to late summer, whereas the flux of G. bulloides peaks later in the season and is sustained until autumn. Likewise, seasonality influences large and small specimens differently, with large shells settling earlier in the season. The similarity of the seasonal delta O-18 patterns between the two species indicates that they calcify in an overlapping depth zone close to the surface. However, their delta C-13 patterns are markedly different (> 1 parts per thousand). Both species have a seasonally variable offset from delta C-13(DIC) that appears to be governed primarily by temperature, with larger offsets associated with higher temperatures. The variable offset from delta C-13(DIC) implies that seasonality of the flux affects the fossil delta C-13 signal, which has implications for reconstruction of the past oceanic carbon cycle. Citation: Jonkers, L., S. van Heuven, R. Zahn, and F. J. C. Peeters (2013), Seasonal patterns of shell flux, delta O-18 and delta C-13 of small and large N. pachyderma (s) and G. bulloides in the subpolar North Atlantic, Paleoceanography, 28, 164-174, doi:10.1002/palo.20018.</p>