2,886 research outputs found
Breast, ovarian, and endometrial malignancies in systemic lupus erythematosus: a meta-analysis
Many-body nodal hypersurface and domain averages for correlated wave functions
We outline the basic notions of nodal hypersurface and domain averages for
antisymmetric wave functions. We illustrate their properties and analyze the
results for a few electron explicitly solvable cases and discuss possible
further developments
Duct Excision is Still Necessary to Rule out Breast Cancer in Patients Presenting with Spontaneous Bloodstained Nipple Discharge
Introduction. Spontaneous nipple discharge is the third most common reason for presentation to a symptomatic breast clinic. Benign and malignant causes of spontaneous nipple discharge continue to be difficult to distinguish. We analyse our experience of duct excisions for spontaneous nipple discharge to try to identify features that raise suspicion of breast cancer and to identify features indicative of benign disease that would be suitable for nonoperative management. Methods. Details of one hundred and ninety-four patients who underwent duct excision for spontaneous nipple discharge between 1995 and 2005 were analysed. Results. Malignant disease was identified in 11 (5.7%) patients, 4 invasive and 7 insitu, which was 10.2% of those presenting with bloodstained discharge. All patients with malignant disease had bloodstained discharge. Discharge due to malignant disease was more likely to be bloodstained than that due to benign causes (Fisher's exact test, 2-tailed P value = 0.00134). Conclusion. Our findings do not support a policy of conservative management of spontaneous bloodstained nipple discharge. Cases of demonstrable spontaneous bloodstained nipple discharge should undergo duct excision to prevent malignant lesions being missed
On the dynamics of a twisted disc immersed in a radiation field
We study the dynamics of a twisted tilted disc under the influence of an
external radiation field. Assuming the effect of absorption and
reemission/scattering is that a pressure is applied to the disc surface where
the local optical depth is of order unity, we determine the response of the
vertical structure and the influence it has on the possibility of instability
to warping. We derive a pair of equations describing the evolution of a small
tilt as a function of radius in the small amplitude regime that applies to both
the diffusive and bending wave regimes. We also study the non linear vertical
response of the disc numerically using an analogous one dimensional slab model.
For global warps, we find that in order for the disc vertical structure to
respond as a quasi uniform shift or tilt, as has been assumed in previous work,
the product of the ratio of the external radiation momentum flux to the local
disc mid plane pressure, where it is absorbed, with the disc aspect ratio
should be significantly less than unity. Namely, this quantity should be of the
order of or smaller than the ratio of the disc gas density corresponding to the
layer intercepting radiation to the mid plane density, . When
this condition is not satisfied the disc surface tends to adjust so that the
local normal becomes perpendicular to the radiation propagation direction. In
this case dynamical quantities determined by the disc twist and warp tend to
oscillate with a large characteristic period ,
where is some 'typical' orbital period of a gas element in the disc.
The possibility of warping instability then becomes significantly reduced. In
addition, when the vertical response is non uniform, the possible production of
shocks may lead to an important dissipation mechanism.Comment: submitted to MNRA
Block-Diagonalization and f-electron Effects in Tight-Binding Theory
We extend a tight-binding total energy method to include f-electrons, and
apply it to the study of the structural and elastic properties of a range of
elements from Be to U. We find that the tight-binding parameters are as
accurate and transferable for f-electron systems as they are for d-electron
systems. In both cases we have found it essential to take great care in
constraining the fitting procedure by using a block-diagonalization procedure,
which we describe in detail.Comment: 9 pages, 6 figure
- …