Fermionic Quasi-free States and Maps in Information Theory

This paper and the results therein are geared towards building a basic toolbox for calculations in quantum information theory of quasi-free fermionic systems. Various entropy and relative entropy measures are discussed and the calculation of these reduced to evaluating functions on the one-particle component of quasi-free states. The set of quasi-free affine maps on the state space is determined and fully characterized in terms of operations on one-particle subspaces. For a subclass of trace preserving completely positive maps and for their duals, Choi matrices and Jamiolkowski states are discussed.Comment: 19 page

Additivity of the Renyi entropy of order 2 for positive-partial-transpose-inducing channels

We prove that the minimal Renyi entropy of order 2 (RE2) output of a positive-partial-transpose(PPT)-inducing channel joint to an arbitrary other channel is equal to the sum of the minimal RE2 output of the individual channels. PPT-inducing channels are channels with a Choi matrix which is bound entangled or separable. The techniques used can be easily recycled to prove additivity for some non-PPT-inducing channels such as the depolarizing and transpose depolarizing channels, though not all known additive channels. We explicitly make the calculations for generalized Werner-Holevo channels as an example of both the scope and limitations of our techniques.Comment: 4 page

Pétrographie characterization of rocks from the Mirabello bay region, Crete, and its application to Minoan archaeology: the provenance of stone implements from Minoan sites

Οι άνθρωποι της Μινωικής Εποχής, στην Ανατολική Κρήτη, χρησιμοποιούσαν μαγματικά και μεταμορφωμένα πετρώματα για την κατασκευή διαφόρων λίθινων σκευών. Αυτά τα συνέλλεγαν από τις κοίτες των ποταμών και την ακτή στην περιοχή κατά μήκος του κόλπου του Μιραμπέλλο ή από ένα κροκαλοπαγές επίκλυσης, το οποίο κυριαρχεί γεωλογικά στην περιοχή αυτή και περιέχει κροκάλες από μαγματικά, μεταμορφωμένα και ιζηματογενή πετρώματα. Η λεπτομερής πετρογραφική περιγραφή φυσικών δειγμάτων, που συλλέχθηκαν από αυτούς τους σχηματισμούς και η σύγκριση τους με λίθινα σκεύη από ανασκαφές, αφενός καθιστά γνωστούς τους λιθολογικούς τύπους που χρησιμοποιήθηκαν και αφετέρου επιβεβαιώνει την πηγή προέ?χυσής τους. Με τη έρευνα αυτή καθίσταται προφανές ότι οι άνθρωποι της Μινωικής Εποχής μπορούσαν μα εκτιμήσουν τη σκληρότητα των λίθων που συνέλλεγαν, σύμφωνα με την επιθυμητή χρήση, καθώς και την αναμενόμενη κόπωση των υλικών, ανάλογα με τη χρήση για την οποία τα προόριζαν, αποφεύγοντας παράλληλα την ανεπιθύμητα χρονοβόρα κατεργασία τους. Με την επιβεβαίωση της λιθολογίας και της πηγής προέλευσης των λίθινων πρώτων υλών γίνεται επίσης αντιληπτό το γεγονός ότι οι άνθρωποι της Μινωικής Εποχής ήταν γνώστες του φυσικού περιβάλλοντος, στον ευρύτερο χώρο των οικισμών τους. Επίσης, μπορεί να εκτιμηθεί και ο χρόνος τον οποίο διέθεταν προκειμένου να βρουν και να συλλέξουν την πρώτη ύλη αλλά και να αξιολογηθεί ο χρόνος κατεργασίας των υλικών, προκειμένου να διαμορφωθούν σε κατάλληλα σκεύη, ανάλογα με τη σκληρότητα τους.The Minoans of East Crete used a variety of igneous and metamorphic rocks as stone implements. These were probably procured in dry riverbeds and beaches located in a region along the Bay of Mirabello or from an onlap conglomerate, which geologically dominates that region and contains rock types of igneous, metamorphic and sedimentary origin. Several rock samples were collected for pétrographie investigation to examine and confirm the source for the igneous rocks. Detailed pétrographie description of natural samples provides the identification of the rocks employed by Minoans and confirms the source of their origin. Apparently the Minoans were able to evaluate the hardness of the stones procured according to the desirable usage and their expected fatigue, thus avoiding unnecessary timeconsuming treatment. The identification of the variable lithotypes used for these implements and the verification of their source regions reveal the time it took to procure the raw materials as well as the time period during which the rocks were employed

Goldstone Bosons in Josephson Junctions

For a microscopic model of a Josephson junction the normal coordinates of the two junction Goldstone bosons are constructed and their dynamical spectrum is computed. The explicit dependence on the phase difference of the two superconductors is calculated

Filament tension and phase-locked drift of meandering scroll waves

Rotating scroll waves are self-organising patterns which are found in many oscillating or excitable systems. Here we show that quasi-periodic (meandering) scroll waves, which include the rotors that organise cardiac arrhythmias, exhibit filament tension when averaged over the meander cycle. With strong filament curvature or medium thickness gradients, however, scroll wave dynamics are governed by phase-locked drift instead of filament tension. Our results are validated in computational models of cycloidal meander and a cardiac tissue model with linear core.Comment: accepted for publication in Physical Review Letters (December 2017

Adaptive Path Planning for Depth Constrained Bathymetric Mapping with an Autonomous Surface Vessel

This paper describes the design, implementation and testing of a suite of algorithms to enable depth constrained autonomous bathymetric (underwater topography) mapping by an Autonomous Surface Vessel (ASV). Given a target depth and a bounding polygon, the ASV will find and follow the intersection of the bounding polygon and the depth contour as modeled online with a Gaussian Process (GP). This intersection, once mapped, will then be used as a boundary within which a path will be planned for coverage to build a map of the Bathymetry. Methods for sequential updates to GP's are described allowing online fitting, prediction and hyper-parameter optimisation on a small embedded PC. New algorithms are introduced for the partitioning of convex polygons to allow efficient path planning for coverage. These algorithms are tested both in simulation and in the field with a small twin hull differential thrust vessel built for the task.Comment: 21 pages, 9 Figures, 1 Table. Submitted to The Journal of Field Robotic

Radionuclide Imaging of Fungal Infections and Correlation with the Host Defense Response

The human response to invading fungi includes a series of events that detect, kill, or clear the fungi. If the metabolic host response is unable to eliminate the fungi, an infection ensues. Some of the host response's metabolic events to fungi can be imaged with molecules labelled with radionuclides. Several important clinical applications have been found with radiolabelled biomolecules of inflammation. 18F-fluorodeoxyglucose is the tracer that has been most widely investigated in the host defence of fungi. This tracer has added value in the early detection of infection, in staging and visualising dissemination of infection, and in monitoring antifungal treatment. Radiolabelled antimicrobial peptides showed promising results, but large prospective studies in fungal infection are lacking. Other tracers have also been used in imaging events of the host response, such as the migration of white blood cells at sites of infection, nutritional immunity in iron metabolism, and radiolabelled monoclonal antibodies. Many tracers are still at the preclinical stage. Some tracers require further studies before translation into clinical use. The application of therapeutic radionuclides offers a very promising clinical application of these tracers in managing drug-resistant fungi

Recommendations in Second Opinion Reports of Neurologic Head and Neck Imaging:Frequency, Referring Clinicians? Compliance, and Diagnostic Yield

BACKGROUND AND PURPOSE: Second opinion reports of neurologic head and neck imaging are requested with increased regularity, and they may contain a recommendation to the clinician. Our aim was to investigate the frequency and determinants of the presence of a recommendation and the adherence by the referring physician to the recommendation in a second opinion neurology head and neck imaging report and the diagnostic yield of these recommendations. MATERIALS AND METHODS: This retrospective study included 994 consecutive second opinion reports of neurology head and neck imaging examinations performed at a tertiary care center. RESULTS: Of the 994 second opinion reports, 12.2% (121/994) contained a recommendation. An oncologic imaging indication was significantly (P = .030) associated with a lower chance of a recommendation in the second opinion report (OR = .67; 95% CI, 0.46?0.96). Clinicians followed 65.7% (88/134) of the recommendations. None of the investigated variables (patient age, sex, hospitalization status, indication for the second opinion report, experience of the radiologist who signed the second opinion report, strength of the recommendation, and whether the recommendation was made due to apparent quality issues of the original examination) were significantly associated with the compliance of the referring physician to this recommendation. The 134 individual recommendations eventually led to the establishment of 52 (38.2%) benign diagnoses and 28 (20.6%) malignant diagnoses, while no definitive diagnosis could be established in 56 (41.2%) cases. CONCLUSIONS: Recommendations are relatively common in second opinion reports of neurology head and neck imaging examinations, though less for oncologic indications. They are mostly followed by requesting physicians, thus affecting patient management. In most cases, they also lead to the establishment of a diagnosis, hence adding value to patient care

Time to Reconsider Routine Percutaneous Biopsy in Spondylodiscitis?

Percutaneous image-guided biopsy currently has a central role in the diagnostic work-up of patients with suspected spondylodiscitis. However, on the basis of recent evidence, the value of routine image-guided biopsy in this disease can be challenged. In this article, we discuss this recent evidence and also share a new diagnostic algorithm for spondylodiscitis that was recently introduced at our institution. Thus, we may move from a rather dogmatic approach in which routine image-guided biopsy is performed in any case to a more individualized use of this procedure. Percutaneous image-guided biopsy, while valuable, is an invasive procedure, and evidence has shown rather disappointing positive microbiologic culture yields of around 33%. Recent evidence also has shown that percutaneous image-guided biopsy rarely adds any new information when blood cultures have positive findings and that an effective empiric treatment can be started in most of cases even when the microbiologic culprit remains unknown. Finally, there is currently no evidence that percutaneous image-guided biopsy improves patient outcome