1,047 research outputs found

    Quantum steering ellipsoids, extremal physical states and monogamy

    Get PDF
    A Corrigendum for this article has been published in 2015 New J. Phys. 17 019501Any two-qubit state can be faithfully represented by a steering ellipsoid inside the Bloch sphere, but not every ellipsoid inside the Bloch sphere corresponds to a two-qubit state. We give necessary and sufficient conditions for when the geometric data describe a physical state and investigate maximal volume ellipsoids lying on the physical-unphysical boundary. We derive monogamy relations for steering that are strictly stronger than the Coffman-Kundu- Wootters (CKW) inequality for monogamy of concurrence. The CKW result is thus found to follow from the simple perspective of steering ellipsoid geometry. Remarkably, we can also use steering ellipsoids to derive non-trivial results in classical Euclidean geometry, extending Eulers inequality for the circumradius and inradius of a triangle.The EPSRC and the ARC Centre of Excellence grant no. CE110001027. DJ is funded by the Royal Society. TR would like to thank the Leverhulme Trust. SJ acknowledges EPSRC grant EP/ K022512/1

    Vrste plesni na kukuruznom klipu uskladištenom u koševima na teritoriji opština Vrnjačka Banja i Kruševac

    Get PDF
    Corn cob owned by individual producers is stored on multiple ways: in barns, attics, sheds etc. If corn cob is not dried properly when stord in barns, it represents ideal foundation for field and storage molds.For our examinations we used corn from 20 barns originating from ten plain and mountain villages in Vrnjacka Banja municipality. Mold isolation was performed on saburo ager on temperature of 27oC. Most commonly isolated sorts of mold were: Penicillium sp., Aspergillus ustus, Alternaria tenuis, Yeast, Mucor mucedo, Fusarium roseum, Aspergillus candidus, Trichoderma viride and Aspergillus flavus. Our results show that dominant role was frequently represented by field molds – Alternaria and Fusarium, most common of storage molds were molds from the genus Aspergillus and Penicillium, and most common progressive decay molds were Mucor and Rhisopos. Infection of grain was by rule 100% with rare exeptions.Kukuruzni klip u vlasništvu individualnih proizvođača skladišti se na više načina: u koševima, tavanima, šupama i dr. Ukoliko se kukuruzni klip, nedovoljno osušen, skladišti u koševe on predstavlja idealnu podlogu za razvoj poljskih i skladišnih plesni. Za ispitivanja smo koristili kukuruz iz 20 koševa koji su poreklom iz 10 sela ravničarskog i planinskog predela sa područja opštine Vrnjačka Banja. Izolaciju plesni vršili smo na Saburo agaru na temperaturi od 27°C. Najčešće su izolovane sledeće vrste plesni: Penicillium sp., Aspergillus ustus, Alternaria tenuis, Kvasnice, Mucor mucedo, Fusarium roseum, Aspergillus candidus, Trichoderma viride i Aspergillus flavus. Naši rezultati pokazuju da su dominantnu ulogu u frekvenciji predstavljale plesni s polja- Alternaria i Fusarium, od plesni uskladištenja najučestalije su bile plesni iz roda Aspergillus i Penicillium, a od plesni uznapredovanog kvarenja Mucor i Rhisopus. Infekcija zrna je bila po pravilu 100% sa retkim odstupanjima

    Exchange Fluctuation Theorem for correlated quantum systems

    Get PDF
    We extend the Exchange Fluctuation Theorem for energy exchange between thermal quantum systems beyond the assumption of molecular chaos, and describe the non-equilibrium exchange dynamics of correlated quantum states. The relation quantifies how the tendency for systems to equilibrate is modified in high-correlation environments. Our results elucidate the role of measurement disturbance for such scenarios. We show a simple application by finding a semi-classical maximum work theorem in the presence of correlations.Comment: Lots of new material added, a figure, and a new author, 13 pages, 1 figure, comments welcom

    A measure of majorisation emerging from single-shot statistical mechanics

    Full text link
    The use of the von Neumann entropy in formulating the laws of thermodynamics has recently been challenged. It is associated with the average work whereas the work guaranteed to be extracted in any single run of an experiment is the more interesting quantity in general. We show that an expression that quantifies majorisation determines the optimal guaranteed work. We argue it should therefore be the central quantity of statistical mechanics, rather than the von Neumann entropy. In the limit of many identical and independent subsystems (asymptotic i.i.d) the von Neumann entropy expressions are recovered but in the non-equilbrium regime the optimal guaranteed work can be radically different to the optimal average. Moreover our measure of majorisation governs which evolutions can be realized via thermal interactions, whereas the nondecrease of the von Neumann entropy is not sufficiently restrictive. Our results are inspired by single-shot information theory.Comment: 54 pages (15+39), 9 figures. Changed title / changed presentation, same main results / added minor result on pure bipartite state entanglement (appendix G) / near to published versio

    Improvement for detection of microcalcifications through clustering algorithms and artificial neural networks

    Get PDF
    A new method for detecting microcalcifications in regions of interest (ROIs) extracted from digitized mammograms is proposed. The top-hat transform is a technique based on mathematical morphology operations and, in this paper, is used to perform contrast enhancement of the mi-crocalcifications. To improve microcalcification detection, a novel image sub-segmentation approach based on the possibilistic fuzzy c-means algorithm is used. From the original ROIs, window-based features, such as the mean and standard deviation, were extracted; these features were used as an input vector in a classifier. The classifier is based on an artificial neural network to identify patterns belonging to microcalcifications and healthy tissue. Our results show that the proposed method is a good alternative for automatically detecting microcalcifications, because this stage is an important part of early breast cancer detectio

    The HEV Ventilator Proposal

    Get PDF
    We propose the design of a ventilator which can be easily manufactured and integrated into the hospital environment to support COVID-19 patients. The unit is designed to support standard ventilator modes of operation, most importantly PRVC (Pressure Regulated Volume Control) and SIMV-PC (Synchronised Intermittent Mandatory Ventilation) modes. The unit is not yet an approved medical device and is in the concept and prototyping stage. It is presented here to invite fast feedback for development and deployment in the face of the COVID-19 pandemic.Comment: 14 pages, 5 figure

    Comparison of bio-inspired algorithms applied to the coordination of mobile robots considering the energy consumption

    Get PDF
    Many applications, related to autonomous mobile robots, require to explore in an unknown environment searching for static targets, without any a priori information about the environment topology and target locations. Targets in such rescue missions can be fire, mines, human victims, or dangerous material that the robots have to handle. In these scenarios, some cooperation among the robots is required for accomplishing the mission. This paper focuses on the application of different bio-inspired metaheuristics for the coordination of a swarm of mobile robots that have to explore an unknown area in order to rescue and handle cooperatively some distributed targets. This problem is formulated by first defining an optimization model and then considering two sub-problems: exploration and recruiting. Firstly, the environment is incrementally explored by robots using a modified version of ant colony optimization. Then, when a robot detects a target, a recruiting mechanism is carried out to recruit a certain number of robots to deal with the found target together. For this latter purpose, we have proposed and compared three approaches based on three different bio-inspired algorithms (Firefly Algorithm, Particle Swarm Optimization, and Artificial Bee Algorithm). A computational study and extensive simulations have been carried out to assess the behavior of the proposed approaches and to analyze their performance in terms of total energy consumed by the robots to complete the mission. Simulation results indicate that the firefly-based strategy usually provides superior performance and can reduce the wastage of energy, especially in complex scenarios

    Discovertebral (Andersson) lesions in severe ankylosing spondylitis: a study using MRI and conventional radiography

    Get PDF
    The objective of this study is to investigate the prevalence of Andersson lesions (AL) in ankylosing spondylitis (AS) patients who will start anti-tumor necrosis factor (TNF) treatment. Radiographs and magnetic resonance imaging (MRI) of the spine were performed before therapy with anti-TNF. ALs were defined as discovertebral endplate destructions on MRI, associated with bone marrow edema and fat replacement or sclerosis, a decreased signal on T1, enhancement after contrast administration (gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA)), and increased signal on T2 and short tau inversion recovery (STIR). Additionally, conventional radiography showed a fracture line, irregular endplates, and increased sclerosis of adjacent vertebral bodies. Fifty-six AS patients were included, 68% males, mean age of 43 years, and mean disease duration of 11 years. The mean bath ankylosing spondylitis disease activity index was 6.4, and 24% of all patients had ankylosis. Only one patient showed a discovertebral abnormality with bone marrow edema of more than 50% of the vertebral bodies adjacent to the intervertebral disk of T7/T8 and T9/T10, a hypodense signal area on T1, and a high signal on STIR. Irregular endplates were depicted, and T1 after Gd-DTPA demonstrated high signal intensity around the disk margins. However, no fracture line was visible on conventional radiology, and therefore, this case was not considered to be an AL. No AL was detected in our AS patients, who were candidates for anti-TNF treatment. One patient showed a discovertebral abnormality on MRI, without a fracture line on conventional radiology. The relative small proportion of patients with a long-established disease might explain this finding for, particularly, an ankylosed spine is prone to develop an AL
    corecore