71 research outputs found

    Decoherence and Programmable Quantum Computation

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    An examination of the concept of using classical degrees of freedom to drive the evolution of quantum computers is given. Specifically, when externally generated, coherent states of the electromagnetic field are used to drive transitions within the qubit system, a decoherence results due to the back reaction from the qubits onto the quantum field. We derive an expression for the decoherence rate for two cases, that of the single-qubit Walsh-Hadamard transform, and for an implementation of the controlled-NOT gate. We examine the impact of this decoherence mechanism on Grover's search algorithm, and on the proposals for use of error-correcting codes in quantum computation.Comment: submitted to Phys. Rev. A 35 double-spaced pages, 2 figures, in LaTe

    Biochemical predictors of outcome of pituitary surgery for cushing's disease

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    Objective: Transsphenoidal surgery (TS) is the primary therapy for Cushing's disease (CD). The aims of this retrospective study were twofold: (i) investigate early and late results of TS forCD, and (ii) evaluate various postoperative tests in order to predict the outcome of TS. Methods: We reviewed the long-term outcome in 79 patients with CD who underwent TS (median follow-up 84 months, range 6-197). Within 2 weeks after surgery, morning serum cortisol concentrations were obtained (n = 78) and corticotropin-releasing hormone (CRH) (n = 53) and metyrapone tests (n = 72) were performed. Three groups of outcome were identified: sustained remission, early failure (persistent CD), and late relapse. Results: Immediate postoperative remission was achieved in 51 patients (65%), whereas 28 patients (35%) had persistent CD after TS. Ten patients developed recurrent CD after initial remission (20%). Morning cortisol: all relapses but one recorded serum cortisol >50 nmol/l. A cortisol threshold value of 200 nmol/l has a positive predictive value of 79% for immediate surgical failure (negative predictive failure [NPV] 97%). CRH test: CRH-stimulated peak cortisol ≥600 nmol/l predicted early failure in 78% (NPV 100%). All relapses recorded CRH-stimulated peak cortisol ≥485 nmol/l. Metyrapone test: 11-deoxycortisol ≥345 nmol/l predicted an early failure in 86% of cases (NPV 94%). Conclusion: Predictive factors of surgical failure are morning cortisol ≥200 nmol/l, 11-deoxycortisol ≥345 nmol/l after metyrapone and CRH-stimulated cortisol ≥600 nmol/l. CRH and/or metyrapone testing are not superior to morning cortisol concentration in the prediction of outcome of TS. Careful long-term follow-up remains necessary independent of the outcome of biochemical testing. Copyrigh

    Sex‑differential non‑specific effects of adjuvanted and non‑adjuvanted rabies vaccines versus placebo on all‑cause mortality in dogs (NERVE‑Dog study) : a study protocol for a randomized controlled trial with a nested case–control study

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    BACKGROUND : It has been proposed that childhood vaccines in high-mortality populations may have substantial impacts on mortality rates that are not explained by the prevention of targeted diseases, nor conversely by typical expected adverse reactions to the vaccines, and that these non-specific effects (NSEs) are generally more pronounced in females. The existence of these effects, and any implications for the development of vaccines and the design of vaccination programs to enhance safety, remain controversial. One area of controversy is the reported association of non-live vaccines with increased female mortality. In a previous randomized controlled trial (RCT), we observed that non-live alum-adjuvanted animal rabies vaccine (ARV) was associated with increased female but not male mortality in young, free-roaming dogs. Conversely, non-live non-adjuvanted human rabies vaccine (NRV) has been associated with beneficial non-specific effects in children. Alum adjuvant has been shown to suppress Th1 responses to pathogens, leading us to hypothesize that alum-adjuvanted rabies vaccine in young dogs has a detrimental effect on female survival by modulating the immune response to infectious and/or parasitic diseases. In this paper, we present the protocol of a 3-arm RCT comparing the effect of alum-adjuvanted rabies vaccine, non-adjuvanted rabies vaccine and placebo on all-cause mortality in an owned, free-roaming dog population, with causal mediation analysis of the RCT and a nested case–control study to test this hypothesis. METHODS : Randomised controlled trial with a nested case–control study. DISCUSSION : We expect that, among the placebo group, males will have higher mortality caused by higher pathogen loads and more severe disease, as determined by haematological parameters and inflammatory biomarkers. Among females, we expect that there will be no difference in mortality between the NRV and placebo groups, but that the ARV group will have higher mortality, again mediated by higher pathogen loads and more severe disease. We anticipate that these changes are preceded by shifts in key serum cytokine concentrations towards an anti-inflammatory immune response in females. If confirmed, these results will provide a rational basis for mitigation of detrimental NSEs of non-live vaccines in high-mortality populations.The RCT reported in this publication is supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. The NCC component of the protocol is supported by the Morris Animal Foundation.http://www.biomedcentral.com/bmcvetresam2023Companion Animal Clinical StudiesVeterinary Tropical Disease

    The Physics of the B Factories

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    Introducing the shape-length illusion

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    The size of an object can be perceived by pinching it between thumb and index finger. Here we show a new haptic illusion in which the length of objects with large local curvature is overestimated. Participants pinched ellipses between the thumb and the index finger and matched the size of the major axis to a set of rectangles which carry no curvature information. Ellipses with high local curvature at the contact areas were consistently rated to be larger than those with smaller curvature. This illusion shows that local shape information can influence judgment the size of an object. © 2013 IEEE

    Two hands perceive better than one

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