235 research outputs found

    Unambiguous comparison of ensembles of quantum states

    Full text link
    We present a solution of the problem of the optimal unambiguous comparison of two ensembles of unknown quantum states (psi_1)^k and (psi_2)^l. We consider two cases: 1) The two unknown states psi_1 and psi_2 are arbitrary states of qudits. 2) Alternatively, they are coherent states of a harmonic oscillator. For the case of coherent states we propose a simple experimental realization of the optimal "comparison" machine composed of a finite number of beam-splitters and a single photodetector.Comment: 7 pages, 3 figure

    Resistance of plant life forms of native and regenerated alpine plant communities to experimental trampling

    Get PDF
    Trampling of vegetation as a result of recreation can adversely affect natural habitats, leading to loss of vegetation and degradation of plant communities. Many studies indicated that intrinsic properties of plant communities appear to be the most important factors determining the response of vegetation to trampling disturbance. Specifically, the dominant life-form of a plant community accounts for more variation in the resistance of communities to trampling than the intensity of the trampling experienced, suggesting that simple assessments based on this trait could guide decisions on access to natural sites. We verify these claims in the Belianske Tatry National Nature Reserve in Slovakia, which has been closed since 1978 due to destruction by mass tourism, with the exception of one trail made accessible since 1993. In researching the resistance of communities according to dominant life forms we adjusted the number of passes according to the minimum (75 tourists) and maximum (225 tourists) daily visitation during the tourist season. The studied communities occur in close proximity to the trails on the saddles through which the open trail passes. Available evidence from our studies suggests that vegetation dominated by hemicryptophytes is more resistant to trampling and recovers from trampling to a greater extent than vegetation dominated by other life forms. Therefore, we selected three alpine communities dominated by hemicryptophytes. In the Juncetum trifidi community, they almost completely dominate, they are mainly composed of grasses. Although they dominate the Junco trifidi-Callunetum vulgaris community, the species, Calluna vulgaris has been added to the woody chamephytes, and thus the woody Chamaephytes achieve a higher cover than in the Juncetum trifidi community. Although in the community Seslerietum tatrae biscutelletosum laevigatae hemicryptophytes dominate, it consists of several plant life forms and its grasses reach greater heights than in previous communities. We found that it is not possible to estimate the resilience of communities to trampling by dominant life forms. Life forms within one community react very similarly, but this statement cannot be generalized globally for all communities. At the same time, we found that if we damage the native community, which subsequently regenerates, the life forms of the community behave differently when damaged repeatedly. More detailed research is needed worldwide, which would point out patterns of behaviour of alpine plant vegetation to trampling

    Incompatible measurements on quantum causal networks

    Get PDF
    The existence of incompatible measurements, epitomized by Heisenberg's uncertainty principle, is one of the distinctive features of quantum theory. So far, quantum incompatibility has been studied for measurements that test the preparation of physical systems. Here we extend the notion to measurements that test dynamical processes, possibly consisting of multiple time steps. Such measurements are known as testers and are implemented by interacting with the tested process through a sequence of state preparations, interactions, and measurements. Our first result is a characterization of the incompatibility of quantum testers, for which we provide necessary and sufficient conditions. Then we propose a quantitative measure of incompatibility. We call this measure the robustness of incompatibility and define it as the minimum amount of noise that has to be added to a set of testers in order to make them compatible. We show that (i) the robustness is lower bounded by the distinguishability of the sequence of interactions used by the tester and (ii) maximum robustness is attained when the interactions are perfectly distinguishable. The general results are illustrated in the concrete example of binary testers probing the time evolution of a single-photon polarization

    Toxoplasma gondii, Neospora caninum and Encephalitozoon cuniculi in Animals from Captivity (Zoo and Circus Animals)

    Get PDF
    Problems with parasitic infections are common in zoological gardens and circuses. In some animals it can lead to several disorders such as systemic disease, reproductive disorders (abortions and neonatal mortality), and even to death if severe illness is untreated. Thus, the aim of this study was to evaluate the prevalence of three common parasites in 74 animals from three zoos, and four circuses in Southern Italy. Antibodies to Toxoplasma gondii, Neospora caninum, and Encephalitozoon cuniculi were detected in 51%, 12%, and 20% of animals, respectively. Co‐infections of T. gondii and N. caninum were reported in seven animals (9%) and co‐infection of T. gondii and E. cuniculi in one animal. T. gondii, N. caninum and E. cuniculi seroprevalence differed in type of diet (P ≤ 0.0001; P ≤ 0.037 and P ≤ 0.004, respectively). T. gondii and E. cuniculi seroprevalence also differed in animal families (P ≤ 0.0001) and according to type of housing (P ≤ 0.003), respectively. Statistical differences were not found in other characteristics (gender, age, country of birth, origin, and contact with cats or dogs). This is the first serological study focusing on protozoan and microsporidian parasites in zoo and circus animals from Southern Italy and the first detection of antibodies to E. cuniculi in camels in Europe

    Numerical implementation of incremental minimization principle for materials with multiple rate-independent dissipative mechanisms

    Get PDF
    The financial support via projects No. GA22-20181S and No. GF21-06569K provided by the Czech Science Foundation is gratefully acknowledged

    Towards an optimal swap gate

    Get PDF
    We present a novel approach that generalizes the well known quantum SWAP gate to higher dimensions and construct a regular quantum gate composed entirely in terms of the generalized CNOT gate that cyclically permutes the states of d qudits for d prime. We also investigate the case for d other than prime. A key feature of the construction design relates to the periodicity evaluation for a family of linear recurrences which we achieve by exploiting generating functions and their factorization over the complex reals

    Biomarkers in adult asthma: a systematic review of 8-isoprostane in exhaled breath condensate

    Get PDF
    Objectives: We aimed to assess the evidence for the use of 8-isoprostane in exhaled breath condensate (EBC) as a biomarker in adult asthma. Design: A systematic review and meta-analysis of EBC 8-isoprostane. Methods: We searched a number of online databases (including PubMed, Embase and Scopus) in January 2016. We included studies of adult non-smokers with EBC collection and asthma diagnosis conducted according to recognised guidelines. We aimed to pool data using random effects meta-analysis and assess heterogeneity using I2. Results: We included twenty studies, the findings from which were inconsistent. Seven studies (n = 329) reported 8-isoprostane levels in asthma to be significantly higher than that of control groups, whilst six studies (n = 403) did not. Only four studies were appropriate for inclusion in a random effects meta-analysis of mean difference. This found a statistically significant between-groups difference of 22pg/ml. Confidence in the result is limited by the small number of studies and by substantial statistical heterogeneity (I2 = 94). Conclusion: The clinical value of EBC 8-isoprostane as a quantitative assessment of oxidative stress in asthma remains unclear due to variability in results and methodological heterogeneity. It is essential to develop a robust and standardised methodology if the use of EBC 8-isoprostane in asthma is to be properly evaluated

    Failure of noninvasive prediction of pulmonary hypertension in patients with idiopathic pulmonary fibrosis

    Get PDF
    Background. Pulmonary hypertension (PH) in patients with advanced idiopathic pulmonary fibrosis (IPF) is a complication connected with unfavorable prognosis. Great efforts have been made in attempting to establish a reliable non-invasive method which would enable detection of this complication. In this context a formula using pulmonary function parameters was published with outstanding results. Methods. We tested the formula in 27 IPF patients who underwent a lung function examination, cardiac ultrasonography and catheterisation on the same day. Results. Pulmonary hypertension was detected by catheterisation in 17 patients (63%). In our group, contrary to the published data, the aforementioned formula was neither useful for detecting patients with a high probability of PH nor as a means of calculating the mean pulmonary artery pressure in individual patients (p=0.502 and p=0.833, respectively). Ultrasound examination reached borderline correlation with the values measured by catheterisation when we compare patients with relevant results (r=0.531, p=0.051). However, the examination gave no usable results in 13 patients (48%). Conclusion. Our data suggests that no reliable, noninvasive method is currently available for detecting and confirming PH in IPF patients. We did not confirm the usefulness of the published formula. Further carefully organised studies will be necessary to verify or refute it

    Elucidating the mechanism of ferrocytochrome c heme disruption by peroxidized cardiolipin

    Get PDF
    The interaction of peroxidized cardiolipin with ferrocytochrome c induces two kinetically and chemically distinct processes. The first is a rapid oxidation of ferrocytochrome c, followed by a slower, irreversible disruption of heme c. The oxidation of ferrocytochrome c by peroxidized cardiolipin is explained by a Fenton-type reaction. Heme scission is a consequence of the radical-mediated reactions initiated by the interaction of ferric heme iron with peroxidized cardiolipin. Simultaneously with the heme c disruption, generation of hydroxyl radical is detected by EPR spectroscopy using the spin trapping technique. The resulting apocytochrome c sediments as a heterogeneous mixture of high aggregates, as judged by sedimentation analysis. Both the oxidative process and the destructive process were suppressed by nonionic detergents and/or high ionic strength. The mechanism for generating radicals and heme rupture is presented
    corecore