9 research outputs found
On Chiral Mesons in AdS/CFT
We analyze the spectra of non-chiral and chiral bifundamental mesons arising
on intersecting D7-branes in . In the absence of magnetic
flux on the curve of intersection, the spectrum is non-chiral, and the dual
gauge theory is conformal in the quenched/probe approximation. For this case we
calculate the dimensions of the bifundamental mesonic operators. We then
consider magnetization of the D7-branes, which deforms the dual theory by an
irrelevant operator and renders the mesons chiral. The magnetic flux spoils the
conformality of the dual theory, and induces a D3-brane charge that becomes
large in the ultraviolet, where the non-normalizable bifundamental modes are
rapidly divergent. An ultraviolet completion is therefore necessary to
calculate the correlation functions in the chiral case. On the other hand, the
normalizable modes are very well localized in the infrared, leading to new
possibilities for local model-building on intersecting D7-branes in warped
geometries.Comment: 32 pages, 4 figure
The Evolution of Pituitary Cysts in Growth Hormone-Treated Children
OBJECTIVES: We have previously shown that pituitary cysts may affect growth hormone secretion. This study sought to determine cyst evolution during growth hormone treatment in children. METHODS: Forty-nine patients with short stature, a pituitary cyst, and at least two brain MRI scans were included. The percent of the pituitary gland occupied by the cyst (POGO) was calculated, and a cyst with a POGO of ≤15% was considered small, while a POGO \u3e15% was considered large. RESULTS: Thirty-five cysts were small, and 14 were large. Five of the 35 small cysts grew into large cysts, while 6 of the 14 large cysts shrunk into small cysts. Of 4 cysts that fluctuated between large and small, 3 presented as large and 1 as small. Small cysts experienced greater change in cyst volume (CV) (mean=61.5%) than large cysts (mean=-0.4%). However, large cysts had a greater net change in CV (mean=44.2 mm) than small cysts (mean=21.0 mm). Older patients had significantly larger mean pituitary volume than younger patients (435.4 mm vs. 317.9 mm) and significantly larger mean CV than younger patients (77.4 mm vs. 45.2 mm), but there was no significant difference in POGO between groups. CONCLUSIONS: Pituitary cyst size can vary greatly over time. Determination of POGO over time is a useful marker for determining the possibility of a pathologic effect on pituitary function since it factors both cyst and gland volume. Large cysts should be monitored closely, given their extreme, erratic behavior