A Characterisation of the Weylian Structure of Space-Time by Means of Low Velocity Tests

The compatibility axiom in Ehlers, Pirani and Schild's (EPS) constructive axiomatics of the space-time geometry that uses light rays and freely falling particles with high velocity, is replaced by several constructions with low velocity particles only. For that purpose we describe in a space-time with a conformal structure and an arbitrary path structure the radial acceleration, a Coriolis acceleration and the zig-zag construction. Each of these quantities give effects whose requirement to vanish can be taken as alternative version of the compatibility axiom of EPS. The procedural advantage lies in the fact, that one can make null-experiments and that one only needs low velocity particles to test the compatibility axiom. We show in addition that Perlick's standard clock can exist in a Weyl space only.Comment: to appear in Gen.Rel.Gra

Robust Prostate Cancer Classification with Siamese Neural Networks

Nuclear magnetic resonance (NMR) is a powerful and non–invasive diagnostic tool. However, NMR scanned images are often noisy due to patient motions or breathing. Although modern Computer Aided Diagnosis (CAD) systems, mainly based on Deep Learning (DL), together with expert radiologists, can obtain very accurate predictions, working with noisy data can induce a wrong diagnose or require a new acquisition, spending time and exposing the patient to an extra dose of radiation. In this paper, we propose a new DL model, based on a Siamese neural network, able to withstand random noise perturbations. We use data coming from the ProstateX challenge and demonstrate the superior robustness of our model to random noise compared to a similar architecture, albeit deprived of the Siamese branch. In addition, our approach is also resistant to adversarial attacks and shows overall better AUC performance

On the radar method in general-relativistic spacetimes.

If a clock, mathematically modeled by a parametrized timelike curve in a general-relativistic spacetime, is given, the radar method assigns a time and a distance to every event which is sufficiently close to the clock. Several geometric aspects of this method are reviewed and their physical interpretation is discussed.Comment: Written version of talk given at 359th WE Heraeus Seminar ``Lasers, Clocks, and Drag-Free. New Technologies for Testing Relativistic Gravity in Space.'' Bremen, 2005; to appear in H. Dittus, C. L{\"a}mmerzahl, S. G. Turyshev (eds.): ``Lasers, Clocks, and Drag-Free Control. Exploration of Relativistic Gravity in Space.'' Springer, 200

Effect of cervical relining of acrylic resin copings on the accuracy of stone dies obtained using a polyether impression material

The purpose of this study was to evaluate the accuracy of the respective dies after polyether elastomeric procedure in the presence or absence of cervical contact of the acrylic resin shell with the cervical region, establishing a comparison to dies obtained with stock trays. This study consisted of three groups with 10 specimens each: 1) acrylic copings without cervical contact, (cn); 2) acrylic copings with cervical contact (cc); 3) perforated stock tray, (st). The accuracy of the resulting dies was verified with the aid of a master crown, precisely fit to the master steel die. ANOVA test found statistically significant differences among groups (p<0.001). Tukey's test found that the smallest discrepancy occurred in group cn, followed by cc, while the st group presented the highest difference (cc x cn: p=0.007; st x cn: p<0.001; st x cc: p<0.001)

Role of host β1- and β2-adrenergic receptors in a murine model of B16 melanoma: functional involvement of β3-adrenergic receptors

Complex interactions between tumor cells and their surrounding compartment are strongly influenced by the host in which the tumor grows. In melanoma, for instance, stress associated norephinephrine (NE), acting at β-adrenergic receptors (β-ARs), stimulates melanoma cell proliferation and tumor angiogenesis. Among β-ARs, β3-ARs play a role acting not only at tumor cells but also at non-neoplastic stromal cells within the melanoma. In the present study, we used a murine model of B16 melanoma to evaluate the role of the host β1- and β2-ARs in melanoma growth and we determined whether the role of β3-ARs can be influenced by the absence of stromal β1- and β2-ARs. As compared to wild type mice, β1/2-AR knockout mice displayed i. increased intratumoral levels of both NE and β3-ARs, as evidentiated at both messenger and protein levels, ii. increased tumor vascularization, iii. decreased tumor cell proliferation but increased tumor cell apoptosis and iv. increased responsiveness to intratumoral injection of the β3-AR blocker L-748,337 in terms of decrease in tumor growth, tumor vascular response, tumor cell proliferation and increase in tumor cell death. These findings together validate the role of β-AR signalling in melanoma microenvironment suggesting that non-neoplastic stromal cells may be targeted by β-AR-related drugs. The additional fact that β3-ARs play an important role in melanoma growth suggest selective β3-AR antagonists as important proapoptotic agents