3,921 research outputs found

    Noisy quantum Monty Hall game

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    The influence of spontaneous emission channel and generalized Pauli channel on quantum Monty Hall Game is analysed. The scheme of Flittney and Abbott is reformulated using the formalism of density matrices. Optimal classical strategies for given quantum strategies are found. The whole presented scheme illustrates how quantum noise may change the odds of a zero-sum game.Comment: 10 pages, 3 figure

    Weakly Enforced Boundary Conditions for the NURBS-Based Finite Cell Method

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    In this paper, we present a variationally consistent formulation for the weak enforcement of essential boundary conditions as an extension to the finite cell method, a fictitious domain method of higher order. The absence of boundary fitted elements in fictitious domain or immersed boundary methods significantly restricts a strong enforcement of essential boundary conditions to models where the boundary of the solution domain coincides with the embedding analysis domain. Penalty methods and Lagrange multiplier methods are adequate means to overcome this limitation but often suffer from various drawbacks with severe consequences for a stable and accurate solution of the governing system of equations. In this contribution, we follow the idea of NITSCHE [29] who developed a stable scheme for the solution of the Laplace problem taking weak boundary conditions into account. An extension to problems from linear elasticity shows an appropriate behavior with regard to numerical stability, accuracy and an adequate convergence behavior. NURBS are chosen as a high-order approximation basis to benefit from their smoothness and flexibility in the process of uniform model refinement

    Entanglement and the Quantum Brachistochrone Problem

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    Entanglement is closely related to some fundamental features of the dynamics of composite quantum systems: quantum entanglement enhances the "speed" of evolution of certain quantum states, as measured by the time required to reach an orthogonal state. The concept of "speed" of quantum evolution constitutes an important ingredient in any attempt to determine the fundamental limits that basic physical laws impose on how fast a physical system can process or transmit information. Here we explore the relationship between entanglement and the speed of quantum evolution in the context of the quantum brachistochrone problem. Given an initial and a final state of a composite system we consider the amount of entanglement associated with the brachistochrone evolution between those states, showing that entanglement is an essential resource to achieve the alluded time-optimal quantum evolution.Comment: 6 pages, 3 figures. Corrected typos in Eqs. 1 and

    Exploring a Non-Minimal Sterile Neutrino Model Involving Decay at IceCube and Beyond

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    We study the phenomenology of neutrino decay together with neutrino oscillations in the context of eV-scale sterile neutrinos. We review the formalism of visible neutrino decay in which one of the decay products is a neutrino that potentially can be observed. We apply the formalism developed for decay to the recent sterile neutrino search performed by IceCube with TeV neutrinos. We show that for ν4\nu_4 lifetime τ4/m41016eV1s\tau_4/m_4 \lesssim 10^{-16} {\rm eV^{-1}s}, the interpretation of the high-energy IceCube analysis can be significantly changed.Comment: 12 pages, 7 figures. Find code at: https://github.com/arguelles/nuSQUIDSDeca

    KMC-2: an X-ray beamline with dedicated diffraction and XAS endstations at BESSY II

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    The KMC-2 beamline is dedicated to provide X-ray radiation with high energy stability and resolution. The experimental setup is optimized towards offering a wide range of methods and sample environments. Two permanent endstations can be used in alternation. DIFFRACTION is a flexible multi-purpose diffractometer, based on a Huber six circle diffractometer in psi geometry. XANES provides the possibility for EXAFS, XANES and X-ray fluorescence measurements at-air

    DIMENSIONS OF TRUST IN THE ACCEPTANCE OF INTER-ORGANIZATIONAL INFORMATION SYSTEMS IN NETWORKS: TOWARDS A SOCIO-TECHNICAL PERSPECTIVE

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    In the context of collaborative networks, networked inter-organizational information systems (IOIS) play a major role by providing a shared virtual space for the informal exchange of semi-structured or unstructured knowledge. Since IT support is seen as crucial for the whole network endeavor, the perspective of system acceptance becomes important. However, discussing IS adoption at the interorganizational level brings trust into the story. Building upon socio-technical theory, this study seeks to understand the role of two dimensions of trust in the acceptance of networked IOIS. A theoretical model is developed and subsequently tested with a sample of 121 German network organizations. Network trust reveals to be important for the perceived usefulness of the system, as the main benefit comes from members’ participation. Trust in technology shows to be an even more relevant determinant for the attitude towards the system. We suggest that future adoption studies should pay more attention on the interplay of both the social- as well as the technical-relations

    Effects of temperature variability on community structure in a natural microbial food web

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    Climate change research has demonstrated that changing temperatures will have an effect on community-level dynamics by altering species survival rates, shifting species distributions, and ultimately, creating mismatches in community interactions. However, most of this work has focused on increasing temperature, and still little is known about how the variation in temperature extremes will affect community dynamics. We used the model aquatic community held within the leaves of the carnivorous plant, Sarracenia purpurea, to test how food web dynamics will be affected by high temperature variation. We tested the community response of the first (bacterial density), second (protist diversity and composition), and third trophic level (predator mortality), and measured community respiration. We collected early and late successional stage inquiline communities from S. purpurea from two North American and two European sites with similar average July temperature. We then created a common garden experiment in which replicates of these communities underwent either high or normal daily temperature variation, with the average temperature equal among treatments. We found an impact of temperature variation on the first two, but not on the third trophic level. For bacteria in the high-variation treatment, density experienced an initial boost in growth but then decreased quickly through time. For protists in the high- variation treatment, alpha-diversity decreased faster than in the normal-variation treatment, beta-diversity increased only in the European sites, and protist community composition tended to diverge more in the late successional stage. The mortality of the predatory mosquito larvae was unaffected by temperature variation. Community respiration was lower in the high-variation treatment, indicating a lower ecosystem functioning. Our results highlight clear impacts of temperature variation. A more mechanistic understanding of the effects that temperature, and especially temperature variation, will have on community dynamics is still greatly needed

    Non-genetic inheritance, fertility and assisted reproductive technologies

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    The concept of non-genetic inheritance is gaining considerable attention in the assisted reproductive technology (ART) community due to the reported differences between children born from ART and those that are conceived naturally. It has been demonstrated that children conceived via ART have differences in fetal growth, birth weight, congenital abnormalities, cardiometabolic parameters, glucose homeostasis as well as changes to body composition compared to children conceived naturally. Although these changes may have a parental contribution and may be influenced by the pathology of infertility there is concern that the technologies themselves may play a role. In support of this, is emerging evidence that aspects of ART technology such as culture media formulation and insemination method can alter offspring phenotype. In addition it is also documented that exposure to environmental factors, such as toxins can impact on offspring gametogenesis such that these perturbations persist through generations. With the increasing use of ART and the development of new technologies it is vital that we understand whether ART can effect non-genetic inheritance so that we can optimise technology and prevent abnormal programming and its impact on all aspects of offspring health including fertility and a possible transmission to subsequent generations.Deirdre Zander-Fox, Nicole O McPherson, Michelle Lan

    Trends in stratospheric minor constituents

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    Photochemical models predict that increasing source gas concentrations are also expected to lead to changes in the concentrations of both catalytically active radical species (such as NO2, ClO, and OH) and inactive reservoir species (such as HNO3, HCl, and H2O). For simplicity, we will refer to all these as trace species. Those species that are expected to have increasing concentration levels are investigated. Additionally, the trace species concentration levels are monitored for unexpected changes on the basis of the measure increase in source gases. Carrying out these investigations is difficult due to the limited data base of measurements of stratospheric trace species. In situ measurements are made only infrequently, and there are few satelliteborne measurements, most over a time space insufficient for trend determination. Instead, ground-based measurements of column content must be used for many species, and interpretation is complicated by contributions from the troposphere or mesosphere or both. In this chapter, we examine existing measurements as published or tabulated

    Yield improvement of non-puddled transplanted Aman rice as influenced by effective weed control under conservation agricultural systems

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    Traditional puddled transplanting (PT) can successfully be replaced by strip-tilled non-puddled transplanting (STNT) because it saves energy, fuel, labour and cost of cultivation (Haque et al., 2016; Islam et al., 2012). Moreover, STNT provides better rice yield than the conventional PT (Haque et al., 2016). But heavy weed infestation can cause a significant yield loss in STNT (Zahan et al., 2014). While conservation agriculture (CA) systems highly relies on herbicide for controlling weeds (Muoni et al., 2014), this study was undertaken to find out the effective herbicidal weed control for strip-tilled non-puddled transplanted aman rice that can ensure the optimum grain yield
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