2,164 research outputs found

    Effects of polarization mode dispersion on polarization-entangled photons generated via broadband pumped spontaneous parametric down-conversion

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    An inexpensive and compact frequency multi-mode diode laser enables a compact two-photon polarization entanglement source via the continuous wave broadband pumped spontaneous parametric down-conversion (SPDC) process. Entanglement degradation caused by polarization mode dispersion (PMD) is one of the critical issues in optical fiber-based polarization entanglement distribution. We theoretically and experimentally investigate how the initial entanglement is degraded when the two-photon polarization entangled state undergoes PMD. We report an effect of PMD unique to broadband pumped SPDC, equally applicable to pulsed pumping as well as cw broadband pumping, which is that the amount of the entanglement degradation is asymmetrical to the PMD introduced to each quantum channel. We believe that our results have important applications in long-distance distribution of polarization entanglement via optical fiber channels.1111Ysciescopu

    Experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction

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    Quantum coherence and entanglement, which are essential resources for quantum information, are often degraded and lost due to decoherence. Here, we report a proof-of-principle experimental demonstration of high fidelity entanglement distribution over decoherence channels via qubit transduction. By unitarily switching the initial qubit encoding to another, which is insensitive to particular forms of decoherence, we have demonstrated that it is possible to avoid the effect of decoherence completely. In particular, we demonstrate high-fidelity distribution of photonic polarization entanglement over quantum channels with two types of decoherence, amplitude damping and polarization-mode dispersion, via qubit transduction between polarization qubits and dual-rail qubits. These results represent a significant breakthrough in quantum communication over decoherence channels as the protocol is input-state independent, requires no ancillary photons and symmetries, and has near-unity success probability.1132Ysciescopu

    Clinical review: Clinical management of atrial fibrillation – rate control versus rhythm control

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    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the critically ill and is associated with adverse outcomes. Although there are plausible benefits from conversion and maintenance of sinus rhythm (the so-called 'rhythm-control' strategy), recent randomized trials have failed to demonstrate the superiority of this approach over the rate-control strategy. Regardless of approach, continuous therapeutic anticoagulation is crucial for stroke prevention. This review addresses the findings of these studies and their implications for clinical management of patients with atrial fibrillation

    Depression in Mid- and Later-Life and Risk of Dementia in Women: A Prospective Study within the Danish Nurses Cohort

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    BACKGROUND: Depression and dementia confer substantial global health burdens, particularly in women. Understanding the association between depression and dementia may inform new targets for prevention and/or early intervention. OBJECTIVE: To investigate the association between depression in mid- and later-life and dementia (all-cause, Alzheimer's disease (AD) or vascular dementia (VaD)) in women. METHODS: A prospective study design. Nurses were followed from age 60 years or entry into the cohort, whichever came last, until date of dementia, death, emigration, or end of follow-up, whichever came first. Cox regression models with age as the underlying timeline were used to estimate the associations between time-varying depression and incident dementia. RESULTS: The study included 25,651 female Danish nurses (≥45 years) participating in the Danish Nurse Cohort. During an average of 23 years of follow-up, 1,232 (4.8%) nurses developed dementia and 8,086 (31.5%) were identified with at least two episodes of treated depression. In adjusted analyses, nurses with depression were at a statistically significant 5.23-fold higher risk of all-cause dementia (aHR 5.23:95% CI, 4.64-5.91) compared to those with no history of depression. The differential effects of depression were greater for VaD (aHR 7.96:95% CI, 5.26-12.0) than AD (aHR 4.64:95% CI, 3.97-5.42). Later life depression (>60 years) (aHR 5.85:95% CI, 5.17-6.64) and recurrent depression (aHR 3.51:95% CI, 2.67-4.61) elevated dementia risk. Severe depression tripled the risk of all cause dementia (aHR 3.14:95% CI, 2.62-3.76). CONCLUSION: Both later life and severe depression substantially increase dementia risk in women, particularly VaD

    Measurement of seismometer orientation using the tangential P-wave receiver function based on harmonic decomposition

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    Accurate determination of the seismometer orientation is a prerequisite for seismic studies including, but not limited to seismic anisotropy. While borehole seismometers on land produce seismic waveform data somewhat free of human-induced noise, they might have a drawback of an uncertain orientation. This study calculates a harmonic decomposition of teleseismic receiver functions from the P and PP phases and determines the orientation of a seismometer by minimizing a constant term in a harmonic expansion of tangential receiver functions in backazimuth near and at 0 s. This method normalizes the effect of seismic sources and determines the orientation of a seismometer without having to assume for an isotropic medium. Compared to the method of minimizing the amplitudes of a mean of the tangential receiver functions near and at 0 s, the method yields more accurate orientations in cases where the backazimuthal coverage of earthquake sources (even in the case of ocean bottom seismometers) is uneven and incomplete. We apply this method to data from the Korean seismic network (52 broad-band velocity seismometers, 30 of which are borehole sensors) to estimate the sensor orientation in the period of 2005−2016. We also track temporal changes in the sensor orientation through the change in the polarity and the amplitude of the tangential receiver function. Six borehole stations are confirmed to experience a significant orientation change (10°−180°) over the period of 10 yr. We demonstrate the usefulness of our method by estimating the orientation of ocean bottom sensors, which are known to have high noise level during the relatively short deployment period

    Brazilin Isolated from Caesalpinia sappan Suppresses Nuclear Envelope Reassembly by Inhibiting Barrier-to-Autointegration Factor Phosphorylation

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    To date, many anticancer drugs have been developed by directly or indirectly targeting microtubules, which are involved in cell division. Although this approach has yielded many anticancer drugs, these drugs produce undesirable side effects. An alternative strategy is needed, and targeting mitotic exit may be one alternative approach. Localization of phosphorylated barrier-to-autointegration factor (BAF) to the chromosomal core region is essential for nuclear envelope compartment relocalization. In this study, we isolated brazilin from Caesalpinia sappan Leguminosae and demonstrated that it inhibited BAF phosphorylation in vitro and in vivo. Moreover, we demonstrated direct binding between brazilin and BAF. The inhibition of BAF phosphorylation induced abnormal nuclear envelope reassembly and cell death, indicating that perturbation of nuclear envelope reassembly could be a novel approach to anticancer therapy. We propose that brazilin isolated from C. sappan may be a new anticancer drug candidate that induces cell death by inhibiting vaccinia-related kinase 1-mediated BAF phosphorylation.X1153Ysciescopu

    Double-Fock superposition interferometry for differential diagnosis of decoherence

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    Interferometric signals are degraded by decoherence, which encompasses dephasing, mixing and any distinguishing which-path information. These three paradigmatic processes are fundamentally different, but, for coherent, single-photon and N00N-states, they degrade interferometric visibility in the very same way, which impedes the diagnosis of the cause for reduced visibility in a single experiment. We introduce a versatile formalism for many-boson interferometry based on double-sided Feynman diagrams, which we apply to a protocol for differential decoherence diagnosis: twin-Fock states vertical bar N, N > with N >= 2 reveal to what extent decoherence is due to path distinguishability or to mixing, while double-Fock superpositions vertical bar N: M > = (vertical bar N, M > + vertical bar M, N >)/root 2 with N > M > 0 additionally witness the degree of dephasing. Hence, double-Fock superposition interferometry permits the differential diagnosis of decoherence processes in a single experiment, indispensable for the assessment of interferometers.open1199sciescopu

    Clinical and molecular characterization of a novel PLIN1 frameshift mutation identified in patients with familial partial lipodystrophy.

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    Perilipin 1 is a lipid droplet coat protein predominantly expressed in adipocytes, where it inhibits basal and facilitates stimulated lipolysis. Loss-of-function mutations in the PLIN1 gene were recently reported in patients with a novel subtype of familial partial lipodystrophy, designated as FPLD4. We now report the identification and characterization of a novel heterozygous frameshift mutation affecting the carboxy-terminus (439fs) of perilipin 1 in two unrelated families. The mutation cosegregated with a similar phenotype including partial lipodystrophy, severe insulin resistance and type 2 diabetes, extreme hypertriglyceridemia, and nonalcoholic fatty liver disease in both families. Poor metabolic control despite maximal medical therapy prompted two patients to undergo bariatric surgery, with remarkably beneficial consequences. Functional studies indicated that expression levels of the mutant protein were lower than wild-type protein, and in stably transfected preadipocytes the mutant protein was associated with smaller lipid droplets. Interestingly, unlike the previously reported 398 and 404 frameshift mutants, this variant binds and stabilizes ABHD5 expression but still fails to inhibit basal lipolysis as effectively as wild-type perilipin 1. Collectively, these findings highlight the physiological need for exquisite regulation of neutral lipid storage within adipocyte lipid droplets, as well as the possible metabolic benefits of bariatric surgery in this serious disease.Wellcome TrustThis is the author accepted manuscript. The final version is available from the American Diabetes Association via http://dx.doi.org/10.2337/db14-010
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