The Lax Pair by Dimensional Reduction of Chern-Simons Gauge Theory

We show that the Nonlinear Schr\"odinger Equation and the related Lax pair in 1+1 dimensions can be derived from 2+1 dimensional Chern-Simons Topological Gauge Theory. The spectral parameter, a main object for the Loop algebra structure and the Inverse Spectral Transform, has appear as a homogeneous part (condensate) of the statistical gauge field, connected with the compactified extra space coordinate. In terms of solitons, a natural interpretation for the one-dimensional analog of Chern-Simons Gauss law is given.Comment: 27 pages, Plain Te

q-Analogue of Shock Soliton Solution

By using Jackson's q-exponential function we introduce the generating function, the recursive formulas and the second order q-differential equation for the q-Hermite polynomials. This allows us to solve the q-heat equation in terms of q-Kampe de Feriet polynomials with arbitrary N moving zeroes, and to find operator solution for the Initial Value Problem for the q-heat equation. By the q-analog of the Cole-Hopf transformation we construct the q-Burgers type nonlinear heat equation with quadratic dispersion and the cubic nonlinearity. In q -> 1 limit it reduces to the standard Burgers equation. Exact solutions for the q-Burgers equation in the form of moving poles, singular and regular q-shock soliton solutions are found.Comment: 13 pages, 5 figure

DeepCut: Object Segmentation from Bounding Box Annotations using Convolutional Neural Networks

In this paper, we propose DeepCut, a method to obtain pixelwise object segmentations given an image dataset labelled with bounding box annotations. It extends the approach of the well-known GrabCut method to include machine learning by training a neural network classifier from bounding box annotations. We formulate the problem as an energy minimisation problem over a densely-connected conditional random field and iteratively update the training targets to obtain pixelwise object segmentations. Additionally, we propose variants of the DeepCut method and compare those to a naive approach to CNN training under weak supervision. We test its applicability to solve brain and lung segmentation problems on a challenging fetal magnetic resonance dataset and obtain encouraging results in terms of accuracy

Arteriovenous malformation of the spermatic cord as the cause of acute scrotal pain: a case report

Arteriovenous malformations of the lower urinary tract are uncommon lesions, usually presenting as scrotal masses. A case of recurrent acute scrotal pain mimicking testicular torsion that was attributed to the presence of an arteriovenous malformation of the spermatic cord is described. To our knowledge this is the first reported case of an arteriovenous malformation of the spermatic cord presenting with acute scrotal pain

Multiple landmark detection using multi-agent reinforcement learning

The detection of anatomical landmarks is a vital step for medical image analysis and applications for diagnosis, interpretation and guidance. Manual annotation of landmarks is a tedious process that requires domain-specific expertise and introduces inter-observer variability. This paper proposes a new detection approach for multiple landmarks based on multi-agent reinforcement learning. Our hypothesis is that the position of all anatomical landmarks is interdependent and non-random within the human anatomy, thus finding one landmark can help to deduce the location of others. Using a Deep Q-Network (DQN) architecture we construct an environment and agent with implicit inter-communication such that we can accommodate K agents acting and learning simultaneously, while they attempt to detect K different landmarks. During training the agents collaborate by sharing their accumulated knowledge for a collective gain. We compare our approach with state-of-the-art architectures and achieve significantly better accuracy by reducing the detection error by 50%, while requiring fewer computational resources and time to train compared to the naïve approach of training K agents separately. Code and visualizations available: https://github.com/thanosvlo/MARL-for-Anatomical-Landmark-Detectio

The value of proton mr-spectroscopy in the differentiation of brain tumours from non-neoplastic brain lesions

Purpose: Our aim was to evaluate the efficacy of Proton-MR Spectroscopy for the differentiation of cranial masses from non-neoplastic brain disorders. Material and method: 33 patients with intracranial mass lesions, 29 patients with non-neoplastic brain lesions: Ischemic-demyelinating-metabolic-benign cystic mass group; As a whole 62 patients: 30 males and 32 females were included in this study. Results: In brain tumours, average Cho/NAA ratio 2.84-NAA/Cr ratio was 0.97, Cho/Cr ratio 2.42 and Cho/MI ratio was 3.51. In non-neoplastic group; NAA/Cr ratio was extremely higher than tumour group, the other ratios were far lower than cranial mass lesions. Average Cho/NAA ratio: 0.50 ± 0.15, Cho/Cr ratio: 1.05 ± 0.14, Cho/MI ratio: 1.07 ± 0.73. Conclusion: Higher Cho/NAA and Cho/MI ratios with lower NAA/Cr ratio were most likely to be malignant. Additional lipid and lactate peaks were generally seen in malignant group

Oblique Parameters and Extra Generations via OPUCEM

Recent improvements to OPUCEM, the tool for calculation of the contributions of various models to oblique parameters, are presented. OPUCEM is used to calculate the available parameter space for the four family Standard Model given the current electroweak precision data. It is shown that even with the restrictions on Higgs boson and new quark masses presented in the 2011 autumn conferences, there is still enough space to allow a fourth generation with Dirac type neutrinos. For Majorana type neutrinos, the allowed region is even larger. The electroweak precision data also favors non-zero mixing between light and fourth generations, thus effectively reducing current experimental limits. Additionally, calculations with OPUCEM show that even 5th and 6th generations are compatible with the existing electroweak precision data, with a probability comparable to or higher than the Standard Model with 3 generations.Comment: 11 pages, 21 figures, 5 tables - Version accepted by EPJ-