Cervical cancer screening : an update

In many countries cervical cancer is the commonest gynaecological cancer. In Malta and in the United States, it is the third most common gynaecological cancer. Countries which introduced organised cervical screening programmes saw a dramatic decrease in incidence and mortality from this cancer.1 In Malta however, its incidence and mortality has remained relatively constant in the last few decades, in keeping with the fact that we lack a national organised call and re-call cervical screening programme.2 Our cervical screening is largely opportunistic and most of it is carried out in the private sector. Although incidence and mortality has not decreased, our present imperfect screening must however have prevented a significant rise in incidence and mortality, because the detection (and treatment) of premalignant cervical lesions has risen over recent decades, in keeping with increased sexual promiscuity.peer-reviewe

The determination of the mechanical parameters of the general uniform polygonal lamina

The motion of rigid bodies infields of force depends on their mass, mass-centre location and moments of inertia. These fundamental quantities, here referred to as mechanical parameters. are determined for the general uniform polygonal lamina. The precise description of polygons through border vectors is followed by the determination of the mechanical parameters of elemental triangular laminae. Introducing a general function o.f area, m-area, effectively integrates the separate parameters so that the study's central theorem, extending the results of triangular laminae, involves only m-area. As the worked example illustrates, the theorem permits easy evaluation of numerical results and lends itself well for computerization purposes.peer-reviewe

Detailed analysis of the effects of stencil spatial variations with arbitrary high-order finite-difference Maxwell solver

Due to discretization effects and truncation to finite domains, many electromagnetic simulations present non-physical modifications of Maxwell's equations in space that may generate spurious signals affecting the overall accuracy of the result. Such modifications for instance occur when Perfectly Matched Layers (PMLs) are used at simulation domain boundaries to simulate open media. Another example is the use of arbitrary order Maxwell solver with domain decomposition technique that may under some condition involve stencil truncations at subdomain boundaries, resulting in small spurious errors that do eventually build up. In each case, a careful evaluation of the characteristics and magnitude of the errors resulting from these approximations, and their impact at any frequency and angle, requires detailed analytical and numerical studies. To this end, we present a general analytical approach that enables the evaluation of numerical discretization errors of fully three-dimensional arbitrary order finite-difference Maxwell solver, with arbitrary modification of the local stencil in the simulation domain. The analytical model is validated against simulations of domain decomposition technique and PMLs, when these are used with very high-order Maxwell solver, as well as in the infinite order limit of pseudo-spectral solvers. Results confirm that the new analytical approach enables exact predictions in each case. It also confirms that the domain decomposition technique can be used with very high-order Maxwell solver and a reasonably low number of guard cells with negligible effects on the whole accuracy of the simulation.Comment: 33 pages, 14 figure

Effectiveness of opportunistic screening for cancer of the cervix uteri

The incidence and mortality of uterine cervical cancer in the Maltese Islands has remained relatively constant in medical records of the last few decades. The aim of this study was to determine the cervical cancer screening history and other characteristics of the invasive cervical cancer cases diagnosed in Malta between 1992 and 2002, from a review of their medical records. Only 5% of the cases reviewed had had regular cervical smears prior to the diagnosis of the invasive lesion. Well organised national cancer screening programmes overseas indicate that if less than 70% of the target population (ages 20 to 65 for cervix) is regularly screened, the incidence and mortality will not decrease.1 In Malta, cervical screening is opportunistic and the percentage and sectors of the target population being screened is unknown. A national study is needed to quantify the number of women undergoing cervical screening and to assess how much of the relevant target population is being screened.peer-reviewe

Multiparameter actuation of a neutrally-stable shell: a flexible gear-less motor

We have designed and tested experimentally a morphing structure consisting of a neutrally stable thin cylindrical shell driven by a multiparameter piezoelectric actuation. The shell is obtained by plastically deforming an initially flat copper disk, so as to induce large isotropic and almost uniform inelastic curvatures. Following the plastic deformation, in a perfectly isotropic system, the shell is theoretically neutrally stable, owning a continuous manifold of stable cylindrical shapes corresponding to the rotation of the axis of maximal curvature. Small imperfections render the actual structure bistable, giving preferred orientations. A three-parameter piezoelectric actuation, exerted through micro-fiber-composite actuators, allows us to add a small perturbation to the plastic inelastic curvature and to control the direction of maximal curvature. This actuation law is designed through a geometrical analogy based on a fully non-linear inextensible uniform-curvature shell model. We report on the fabrication, identification, and experimental testing of a prototype and demonstrate the effectiveness of the piezoelectric actuators in controlling its shape. The resulting motion is an apparent rotation of the shell, controlled by the voltages as in a "gear-less motor", which is, in reality, a precession of the axis of principal curvature.Comment: 20 pages, 9 figure