This work presents our contribution to a data challenge organized by the French Radiology Society during the Journées Francophones de Radiologie in October 2018. This challenge consisted in ...classifying MR images of the knee with respect to the presence of tears in the knee menisci, on meniscal tear location, and meniscal tear orientation.
We trained a mask region-based convolutional neural network (R-CNN) to explicitly localize normal and torn menisci, made it more robust with ensemble aggregation, and cascaded it into a shallow ConvNet to classify the orientation of the tear.
Our approach predicted accurately tears in the database provided for the challenge. This strategy yielded a weighted AUC score of 0.906 for all three tasks, ranking first in this challenge.
The extension of the database or the use of 3D data could contribute to further improve the performances especially for non-typical cases of extensively damaged menisci or multiple tears.
We consider the out-of-equilibrium behavior of a general class of mesoscopic devices composed of several superconducting or/and normal metal leads separated by quantum dots. Starting from a ...microscopic Hamiltonian description, we provide a nonperturbative approach to quantum electronic transport in the tunneling amplitudes between dots and leads: using the equivalent of a path integral formulation, the lead degrees of freedom are integrated out in order to compute both the current and the current correlations (noise) in this class of systems, in terms of the dressed Green's function matrix of the quantum dots. In order to illustrate the efficiency of this formalism, we apply our results to the "all superconducting Cooper pair beam splitter," a device composed of three superconducting leads connected via two quantum dots, where crossed Andreev reflection operates Cooper pair splitting. Commensurate voltage differences between the three leads allow us to obtain expressions for the current and noise as a function of the Keldysh Nambu Floquet dressed Green's function of the dot system. This voltage configuration allows the occurrence of nonlocal processes involving multiple Cooper pairs which ultimately lead to the presence of nonzero DC currents in an out-of-equilibrium situation. We investigate in detail the results for the noise obtained numerically in the specific case of opposite voltages, where the transport properties are dominated by the so called "quartet processes," involving the coherent exchange of two Cooper pairs among all three superconducting terminals. We show that these processes are noiseless in the nonresonant case, and that this property is also observed for other voltage configurations. When the dots are in a resonant regime, the noise characteristics change qualitatively, with the appearance of giant Fano factors.
This work presents our contribution to one of the data challenges organized by the French Radiology Society during the Journées Francophones de Radiologie. This challenge consisted in segmenting the ...kidney cortex from coronal computed tomography (CT) images, cropped around the cortex.
We chose to train an ensemble of fully-convolutional networks and to aggregate their prediction at test time to perform the segmentation. An image database was made available in 3 batches. A first training batch of 250 images with segmentation masks was provided by the challenge organizers one month before the conference. An additional training batch of 247 pairs was shared when the conference began. Participants were ranked using a Dice score.
The segmentation results of our algorithm match the renal cortex with a good precision. Our strategy yielded a Dice score of 0.867, ranking us first in the data challenge.
The proposed solution provides robust and accurate automatic segmentations of the renal cortex in CT images although the precision of the provided reference segmentations seemed to set a low upper bound on the numerical performance. However, this process should be applied in 3D to quantify the renal cortex volume, which would require a marked labelling effort to train the networks.
The aim of the present paper was to review the literature concerning the dimensional stability of dental elastomeric impression materials, to support recommendations to control the variables that ...influence the accuracy of these materials. An electronic search of the Scopus and PubMed databases was performed in November 2010. Articles were selected according to the following inclusion criteria: investigation of the dimensional stability of dental elastomers, an experimental study, sample size reported, laboratory tests described, and published in an English language peer-reviewed journal. The search resulted in 47 articles published between 1958 and 2008; of these, 24 were selected for inclusion in the present study. Great variability was discovered in the experimental methodologies used, such as different working times, temperatures and storage mediums for the impressions, impression techniques, material thicknesses, tray types, and methods of evaluation. Despite the lack of standardization among the studies, this review supports the following recommendations to control the dimensional stability: impressions should be stored at temperatures between 21 +/- 2 degrees C; polyether impressions should be stored in an environment with a relative humidity below 50%; time until pouring has been settled for each elastomer material.
The definitive biography of Soviet Jewish dissident writer Vasily Grossman
If Vasily Grossman's 1961 masterpiece, Life and Fate, had been published during his lifetime, it would have reached the ...world together with Pasternak's Doctor Zhivago and before Solzhenitsyn's Gulag. But Life and Fate was seized by the KGB. When it emerged posthumously, decades later, it was recognized as the War and Peace of the twentieth century. Always at the epicenter of events, Grossman (1905-1964) was among the first to describe the Holocaust and the Ukrainian famine. His 1944 article "The Hell of Treblinka" became evidence at Nuremberg. Grossman's powerful anti-totalitarian works liken the Nazis' crimes against humanity with those of Stalin. His compassionate prose has the everlasting quality of great art. Because Grossman's major works appeared after much delay we are only now able to examine them properly. Alexandra Popoff's authoritative biography illuminates Grossman's life and legacy.
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