deletions | additions       diff --git a/sectionAnalysis_of_N.tex b/sectionAnalysis_of_N.tex  index dc3ba87..3cd6881 100644  --- a/sectionAnalysis_of_N.tex  +++ b/sectionAnalysis_of_N.tex 
...
Our study is not the first to look for long filaments associated with spiral structure. \citet{Ragan_2014} and Wang et al. (2015) have undertaken similar studies. However, ours is the first study to specifically look for bones in regions we are most likely to find them, that is, elongated along the galactic plane. Moreover, ours is the only study to create a quantitative set of criteria capable of defining this new class of objects (i.e. galactic "bones").   In the former study, \citet{Ragan_2014} undertook a blind search (not restricted to latitudes where the mid-plane should lie) for long thin filaments (> $1^\circ$) in the first quadrant of the Milky Way, using near and mid-infrared images. In addition to confirming that Nessie lies along the Scutum arm, \citet{Ragan_2014} find seven GMFs of which only one, GMF 20.0-17.9, is said to be associated with Galactic structure (declared a spur of the Scutum-Centaurus arm). Our strongest bone candidate, BC\_18.88-0.09, is a subsection of GMF 20.0-17.9, but, unlike \citet{Ragan_2014}, we argue that BC\_18.88-0.09 runs right down the spine of the Scutum-Centaurus arm in \texit{p-v} space. We believe the discrepancy arises due to a difference in methodology. \citet{Ragan_2014} group neighboring IRDCs into a single filament, despite a) breaks in the extinction feature and b) kinks in velocity structure. Since grouping several IRDCs to make a longer structure violates our criteria 1 and 6, we only consider the continuous and kinematically coherent part of the filament, which is remarkably parallel to the Scutum-Centaurus arm in \textit{p-v} space. Likewise, in figure 4 from \citet{Ragan_2014} (analogous to our figure \ref{fig:skeleton}), they represent filaments as straight lines connecting velocities measured at the tips of the filaments while we represent filaments as sets of points whose velocities are determined by the BGPS, HOPS, MALT90, and GRS surveys. We compare our p-p and p-v \textit{p-v}  analysis of BC\_18.88-0.08 with the analysis from \citet{Ragan_2014} in figure \ref{fig:ragan_comp}. Since \citet{Ragan_2014} find little or no association with their filaments and Galactic structure, they speculate that perhaps we are not as sensitive to spiral arm filaments in the first quadrant, or that the frequency and orientation of spiral arm filaments in the first quadrant is different than the fourth. Since three of our strongest bone candidates (BC\_18.88-0.09, BC\_26.94-0.30, BC\_25.24-0.45) all lie in the first quadrant, we argue against the above speculations. Once again, we attribute the discrepancy not to a difference in frequency or sensitivity, but to a difference in methodology. Unlike \citet{Ragan_2014}, we never used minimum angular length as a criterion because no bone is likely to be as long as Nessie, given its extremely favorable position on the sky. As a result, we argue that bones are not necessarily the longest features on the sky, but the longest features that have incredibly high (>50:1) aspect ratios when compared to the typical Giant Molecular Cloud. Since parts of GMFs from \citet{Ragan_2014} are too diffuse to allow for the measurement of their widths, no complete GMF from that study could reasonably meet our bone definition. Thus, a clear and consistent description of a bone is critical, and, in future studies, we plan to continue to apply the criteria above to achieve consistency.