Neuroblastoma: a review of 21 cases presenting with spinal cord compression

The records of 21 children with neuroblastoma presenting with spinal cord compression, encountered over 17 years, were reviewed. Thirteen patients (61%) survive, free of neuroblastoma, at intervals ranging from nine months to 192 months (median, 78 months) from the time of diagnosis. The explanation for this relatively high survival rate was sought in an analysis of the cases which took into account age, site, extent of disease, and histology. The most significant features to emerge were the unusually high proportion of children under 12 months of age at presentation (11 of 21) most of whom survive (9 of 11) and the low incidence (3 of 21) of detectable at the time of diagnosis. The absence of a paraspinal mass was an unfavourable prognostic features (1 of 6 survives) whilst if a paraspinal mass was present, its anatomical level did not influence survival. In particular, children with retroperitoneal tumors fared no worse (survival, 6 of 7) than those with primary tumors at other sites (survival, 6 of 8). Morbidity was high (6 of 13), principally in infants with spinal cord compression from birth. Survival was also related to the histologic maturity of the tumor, even in the presence of metastases. Recommendations for management are made.     

Computing Hitting Set Kernels By AC0-Circuits

Theory of Computing Systems - Given a hypergraph H = (V,E), what is the smallest subset $X \subseteq V$ such that e ∩ X≠∅ holds for all e ∈ E? This problem, known as the...     

Long term stability of electrocaloric response in barium zirconate titanate

The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr_0.2Ti_0.8)O₃ ceramics which reveal that the adiabatic temperature change, polarization-electric field hysteresis loops and dielectric permittivity/loss show stable behavior up to 10⁵ cycles. We further demonstrate that the loss in electrocaloric response observed after 10⁵ cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 10⁵ cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 10⁶ cycles, much higher than achieved in commercially available barium titanate ceramics.     

A probabilistic model for discretionary lane change proposals in highway driving situations

This contribution presents a novel probabilistic approach for the generation of discretionary lane change proposals with a focus on highway driving situations. The developed model is based on the quantification of the utility of driving lanes. It generates a lane change proposal if the current driving lane is unsatisfactory in the sense that the desired velocity of the automated vehicle is undershot because of a slow preceding vehicle. A driving simulator study was conducted to create a dataset for the optimization of the model parameters. The optimization goal is to accurately match the timings of the lane change intentions of all participants. Finally, the applicability of the model is shown on real data from a test vehicle.

     

Overlaps in Requirements Engineering

Although overlap between specifications—that is the incorporation of elements which designate common aspects of the system of concern—is a precondition for specification inconsistency, it has only been a side concern in requirements engineering research. This paper is concerned with overlaps. It defines overlap relations in terms of specification interpretations, identifies properties of these relations which are derived from the proposed definition, shows how overlaps may affect the detection of inconsistency; shows how specifications could be rewritten to reflect overlap relations and still be amenable to consistency checking using theorem proving; analyses various methods that have been proposed for identifying overlaps with respect to the proposed definition; and outlines directions for future research.