Breastfeeding history, pregnancy experience and risk of breast cancer.

Epidemiological evidence suggests that breastfeeding protects against breast cancer. Whether an effect of age at first breastfeeding is independent of an effect of age at first birth is unclear. We hypothesized that nausea and vomiting in pregnancy, which are associated with elevated serum oestradiol levels during pregnancy, may increase risk. Cases were 452 parous, premenopausal women, 40 years or younger, diagnosed with breast cancer in Los Angeles County from July 1983 to December 1988. Control subjects were matched to cases on age, race, parity and neighbourhood. Pregnancy and breastfeeding histories were obtained from in-person interviews. Odds of breast cancer among women who breastfed for at least 16 months relative to those among women who did not breastfeed was 0.66 [95% confidence interval (CI) 0.41-1.05]. Number of children breastfed was not associated with risk. Risk was lower in women who first breastfed at older ages. Having ever been treated for nausea or vomiting during pregnancy was associated with an increased risk, especially in women experiencing recent pregnancies (OR = 2.03, 95% CI 1.05-3.92). These results support a protective role of breastfeeding and an adverse role of nausea or vomiting during pregnancy in the development of premenopausal breast cancer, especially in the years immediately following pregnancy

The Landau-Ginzburg to Calabi-Yau Dictionary for D-Branes

Based on work by Orlov, we give a precise recipe for mapping between B-type D-branes in a Landau-Ginzburg orbifold model (or Gepner model) and the corresponding large-radius Calabi-Yau manifold. The D-branes in Landau-Ginzburg theories correspond to matrix factorizations and the D-branes on the Calabi-Yau manifolds are objects in the derived category. We give several examples including branes on quotient singularities associated to weighted projective spaces. We are able to confirm several conjectures and statements in the literature.Comment: 24 pages, refs added + minor correctio

Recanalization of chronically occluded aortocoronary saphenous vein bypass grafts by extended infusion of urokinase: Initial results and short-term clinical follow-up

AbstractChronic occlusion of saphenous vein aortocoronary bypass grafts is a common problem. Although percutaneous transluminal angioplasty of a saphenous vein with a stenotic lesion is feasible, angioplasty alone of a totally occluded vein graft yields uniformly poor results. Patients with such occlusion are often subjected to repeat aortocoronary bypass surgery. Experience with a new technique that allows angioplasty to be performed in a totally occluded saphenous vein bypass graft is reported. This technique utilizes infusion of prolonged low dose urokinase directly into the proximal portion of the occluded graft.Forty-six consecutive patients with 47 totally occluded grafts were studied. Patients had undergone end to side saphenous vein bypass grafting 1 to 13 (mean 7) years previously. All patients presented with new or worsening angina pectoris with ST-T changes or non-Q wave acute myocardial infarction and all had a totally occluded saphenous vein bypass graft. The new technique entailed the positioning of an angiographic catheter into the stub of the occluded graft and the advancement of an infusion wire into the graft. Patients were returned to the coronary care unit, where urokinase was delivered at a dose of 100,000 to 250,000 U/h. The total dose of urokinase ranged from 0.7 to 9.8 million U over 7.5 to 77 h (mean 31). After therapy, recanalization was seen in 37 (79%) of the 47 grafts.In 20 successfully treated patients, angiography was performed 1 to 24 (mean 11) months after treatment; 13 (65%) of these grafts were patent. It is concluded that direct, extended, low dose infusion of urokinase in a totally occluded saphenous vein bypass graft offers a promising alternative to repeat bypass surgery

Infrasound initiates directional fast-start escape responses in juvenile roach Rutilus rutilus

Acoustic stimuli within the sonic range are effective triggers of C-type escape behaviours in fish. We have previously shown that fish have an acute sensitivity to infrasound also, with acceleration thresholds in the range of 10(-5) m s(-2). In addition, infrasound at high intensities around 10(-2) m s(-2) elicits strong and sustained avoidance responses in several fish species. In the present study, the possible triggering of C-escapes by infrasonic single-cycle vibrations was examined in juvenile roach Rutilus rutilus. The fish were accelerated in a controlled and quantifiable manner using a swing system. The applied stimuli simulated essential components of the accelerations that a small fish would encounter in the hydrodynamic flow field produced by a predatory fish. Typical C- and S-type escape responses were induced by accelerations within the infrasonic range with a threshold of 0.023 m s(-2) for an initial acceleration at 6.7 Hz. Response trajectories were on average in the same direction as the initial acceleration. Unexpectedly, startle behaviours mainly occurred in the trailing half of the test chamber, in which the fish were subjected to linear acceleration in combination with compression, i.e. the expected stimuli produced by an approaching predator. Very few responses were observed in the leading half of the test chamber, where the fish were subjected to acceleration and rarefaction, i.e. the stimuli expected from a suction type of predator. We conclude that particle acceleration is essential for the directionality of the startle response to infrasound, and that the response is triggered by the synergistic effects of acceleration and compression

Fractional two-branes, toric orbifolds and the quantum McKay correspondence

We systematically study and obtain the large-volume analogues of fractional two-branes on resolutions of orbifolds C^3/Z_n. We study a generalisation of the McKay correspondence proposed in hep-th/0504164 called the quantum McKay correspondence by constructing duals to the fractional two-branes. Details are explicitly worked out for two examples -- the crepant resolutions of C^3/Z_3 and C^3/Z_5.Comment: 34 pages, 2 figures, LaTeX (JHEP3 style); (v2) typos corrected; (v3) sec 3 reorganise

D-branes in Toroidal Orbifolds and Mirror Symmetry

We study D-branes extended in T^2/Z_4 using the mirror description as a tensor product of minimal models. We describe branes in the mirror both as boundary states in minimal models and as matrix factorizations in the corresponding Landau-Ginzburg model. We isolate a minimal set of branes and give a geometric interpretation of these as D1-branes constrained to the orbifold fixed points. This picture is supported both by spacetime arguments and by the explicit construction of the boundary states, adapting the known results for rational boundary states in the minimal models. Similar techniques apply to a larger class of toroidal orbifolds.Comment: 30 pages, 2 figure

D-brane superpotentials and RG flows on the quintic

The behaviour of D2-branes on the quintic under complex structure deformations is analysed by combining Landau-Ginzburg techniques with methods from conformal field theory. It is shown that the boundary renormalisation group flow induced by the bulk deformations is realised as a gradient flow of the effective space time superpotential which is calculated explicitly to all orders in the boundary coupling constant.Comment: 24 pages, 1 figure, v2:Typo in (3.14) correcte

Moduli Webs and Superpotentials for Five-Branes

We investigate the one-parameter Calabi-Yau models and identify families of D5-branes which are associated to lines embedded in these manifolds. The moduli spaces are given by sets of Riemann curves, which form a web whose intersection points are described by permutation branes. We arrive at a geometric interpretation for bulk-boundary correlators as holomorphic differentials on the moduli space and use this to compute effective open-closed superpotentials to all orders in the open string couplings. The fixed points of D5-brane moduli under bulk deformations are determined.Comment: 41 pages, 1 figur