Interlayer tunneling and gap anisotropy in high-temperature superconductors.

A quantitative analysis of a recent model of high-temperature superconductors based on an interlayer tunneling mechanism is presented. This model can account well for the observed magnitudes of the high transition temperatures in these materials and implies a gap that does not change sign, can be substantially anisotropic, and has the same symmetry as the crystal. The experimental consequences explored so far are consistent with the observations.

Non-steroidal anti-inflammatory drugs and the risk of oral cancer: a nested case-control study.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) seem to prevent several types of cancer, but could increase the risk of cardiovascular complications. We investigated whether use of NSAIDs was associated with a change in the incidence of oral cancer or overall or cardiovascular mortality. METHODS: We undertook a nested case-control study to analyse data from a population-based database (Cohort of Norway; CONOR), which consisted of prospectively obtained health data from all regions of Norway. People with oral cancer were identified from the 9241 individuals in CONOR who were at increased risk of oral cancer because of heavy smoking (15 pack-years), and matched controls were selected from the remaining heavy smokers (who did not have cancer). FINDINGS: We identified and analysed 454 (5%) people with oral cancer (279 men, 175 women, mean [SD] age at diagnosis 63.3 [13.2] years) and 454 matched controls (n=908); 263 (29%) had used NSAIDs, 83 (9%) had used paracetamol (for a minimum of 6 months), and 562 (62%) had used neither drug. NSAID use (but not paracetamol use) was associated with a reduced risk of oral cancer (including in active smokers; hazard ratio 0.47, 95% CI 0.37-0.60, p<0.0001). Smoking cessation also lowered the risk of oral cancer (0.41, 0.32-0.52, p<0.0001). Additionally, long-term use of NSAIDs (but not paracetamol) was associated with an increased risk of cardiovascular-disease-related death (2.06, 1.34-3.18, p=0.001). NSAID use did not significantly reduce overall mortality (p=0.17). INTERPRETATION: Long-term use of NSAIDs is associated with a reduced incidence of oral cancer (including in active smokers), but also with an increased risk of death due to cardiovascular disease. These findings highlight the need for a careful risk-benefit analysis when the long-term use of NSAIDs is considered.

Anomalous scaling dimensions and stable charged fixed point of type-II superconductors

The critical properties of a type-II superconductor model are investigated using a dual vortex representation. Computing the propagators of gauge field A and dual gauge field h in terms of a vortex correlation function, we obtain the values eta(A) = 1 and eta(h) = 1 for their anomalous dimensions. This provides support for a dual description of the Ginzburg-Landau theory of type-II superconductors in the continuum limit, as well as for the existence of a stable charged fixed point of the theory, not in the 3D XY universality class.

Hausdorff dimension of critical fluctuations in abelian gauge theories

The geometric properties of the critical fluctuations in Abelian gauge theories such as the Ginzburg-Landau model are analyzed in zero background field. Using a dual description, we obtain scaling relations between exponents of geometric and thermodynamic nature. In particular, we connect the anomalous scaling dimension eta of the dual matter field to the Hausdorff dimension D(H) of the critical fluctuations, which are fractal objects. The connection between the values of eta and D(H), and the possibility of having a thermodynamic transition in finite background field, is discussed.

Criticality versus q in the (2+1)-dimensional Zq clock model.

Using Monte Carlo simulations we have studied the d=3 Z(q) clock model in two different representations, the phase representation and the loop-gas/dumbbell-gas representation. We find that for q> or =5 the critical exponents alpha and nu for the specific heat and the correlation length, respectively, take on values corresponding to the case q--> infinity, the XY model. Hence in terms of critical properties the limiting behavior is reached already at q=5.