Time-reversal ultrawideband breast imaging: pulse design criteria considering multiple tumors with unknown tissue properties

Pulse design is investigated for time-reversal (TR) imaging as applied to ultrawideband (UWB) breast cancer detection. Earlier it has been shown that a suitably-designed UWB pulse may help to improve imaging performance for a single-tumor breast phantom with predetermined lesion properties. The current work considers the following more general and practical situations: presence of multiple malignancies with unknown tumor size and dielectric properties. Four pulse selection criteria are proposed with each focusing on one of the following aspects: eliminating signal clutter generated by tissue inhomogeneities, canceling mutual interference among tumors, improving image resolution, and suppressing artifacts created by sidelobe of the target response. By applying the proposed criteria, the shape parameters of UWB waveforms with desirable characteristics are identified through search of all the possible pulses. Simulation example using a numerical breast phantom, comprised of two tumors and structured clutter distribution, demonstrates the effectiveness of the proposed approach. Specifically, a tradeoff between the image resolution and signal-to-clutter contrast (SCC) is observed in terms of selection of the excitation waveforms.

Challenges to Slovakia and Poland health policy decisions: use of investment treaties to claim compensation for reversal of privatisation/liberalisation policies

Investment treaties, and possibly the EU Treaty itself, are being used by multinational companies Penta and Eureko to try and force the Slovak government to pay compensation for reversing health privatisation and liberalisation policies. Similar action has been used against the Polish government by Eureko to win compensation worth nearly 2 billion Euros and a policy commitment to further privatisation.

The vague, the viral, the parasitic: Piranesi's metropolis

In mid-18th century Giovanni Battista Piranesi’s etchings systematically document the old and new monuments, decrepit buildings and broken down infrastructures of a Rome that continues to inhabit and reinvent its past. His views of Rome offer a devastating account of the blurring of distinctions and articulations that time, use and neglect have imposed on the old differentiations of the urban and the rural, the public and the private, the monumental and the domestic in the 18th century city. Rome becomes for Piranesi the laboratory for a questioning of architecture that places his work well beyond the debate on style and on the origin that dominated the architectural discourse of his time. This paper suggests that Piranesi’s images anticipate the dispersion and sprawl of the city of today, in which the ‘vague’, the ‘viral’ and the ‘parasitic’ become modes of inhabitation and of transient negotiated definition. In the Antichità di Roma, ancient buildings are represented not only in their large scale and magnificence, but also in their decay and reversal to a state of naturalness. These works, together with the acute observations of the Vedute di Roma, provide the materials that are then dislocated, manipulated, cloned and endlessly mutated by Piranesi in the synthesis of the Campo Marzio dell’Antica Roma, in which the historical city is almost entirely dissolved and replaced by an extraordinary congestion of fragments. When they are re-examined on the grounds of contemporary architectural and urban theory, the sites of Piranesi's views reveal anticipations of phenomena that affect the metropolis of today. Political, social and economic conditions have changed dramatically, but the questions asked of architecture in and by these sites challenge the definition of an architecture of style, forms and boundaries - in the 18th century as well as in the 21st -in favour of an architecture of change.